9f6a67ba17
--HG-- extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%401209
4470 lines
146 KiB
C
4470 lines
146 KiB
C
/*
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** 2001 September 15
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** This is the implementation of the page cache subsystem or "pager".
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**
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** The pager is used to access a database disk file. It implements
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** atomic commit and rollback through the use of a journal file that
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** is separate from the database file. The pager also implements file
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** locking to prevent two processes from writing the same database
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** file simultaneously, or one process from reading the database while
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** another is writing.
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**
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** @(#) $Id$
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*/
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#ifndef SQLITE_OMIT_DISKIO
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#include "sqliteInt.h"
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#include "os.h"
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#include "pager.h"
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#include <assert.h>
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#include <string.h>
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/*
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** Macros for troubleshooting. Normally turned off
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*/
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#if 0
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#define sqlite3DebugPrintf printf
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#define PAGERTRACE1(X) sqlite3DebugPrintf(X)
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#define PAGERTRACE2(X,Y) sqlite3DebugPrintf(X,Y)
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#define PAGERTRACE3(X,Y,Z) sqlite3DebugPrintf(X,Y,Z)
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#define PAGERTRACE4(X,Y,Z,W) sqlite3DebugPrintf(X,Y,Z,W)
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#define PAGERTRACE5(X,Y,Z,W,V) sqlite3DebugPrintf(X,Y,Z,W,V)
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#else
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#define PAGERTRACE1(X)
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#define PAGERTRACE2(X,Y)
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#define PAGERTRACE3(X,Y,Z)
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#define PAGERTRACE4(X,Y,Z,W)
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#define PAGERTRACE5(X,Y,Z,W,V)
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#endif
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/*
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** The following two macros are used within the PAGERTRACEX() macros above
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** to print out file-descriptors.
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**
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** PAGERID() takes a pointer to a Pager struct as it's argument. The
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** associated file-descriptor is returned. FILEHANDLEID() takes an OsFile
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** struct as it's argument.
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*/
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#define PAGERID(p) ((int)(p->fd))
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#define FILEHANDLEID(fd) ((int)fd)
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/*
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** The page cache as a whole is always in one of the following
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** states:
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**
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** PAGER_UNLOCK The page cache is not currently reading or
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** writing the database file. There is no
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** data held in memory. This is the initial
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** state.
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**
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** PAGER_SHARED The page cache is reading the database.
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** Writing is not permitted. There can be
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** multiple readers accessing the same database
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** file at the same time.
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**
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** PAGER_RESERVED This process has reserved the database for writing
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** but has not yet made any changes. Only one process
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** at a time can reserve the database. The original
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** database file has not been modified so other
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** processes may still be reading the on-disk
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** database file.
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**
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** PAGER_EXCLUSIVE The page cache is writing the database.
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** Access is exclusive. No other processes or
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** threads can be reading or writing while one
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** process is writing.
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**
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** PAGER_SYNCED The pager moves to this state from PAGER_EXCLUSIVE
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** after all dirty pages have been written to the
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** database file and the file has been synced to
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** disk. All that remains to do is to remove or
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** truncate the journal file and the transaction
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** will be committed.
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**
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** The page cache comes up in PAGER_UNLOCK. The first time a
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** sqlite3PagerGet() occurs, the state transitions to PAGER_SHARED.
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** After all pages have been released using sqlite_page_unref(),
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** the state transitions back to PAGER_UNLOCK. The first time
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** that sqlite3PagerWrite() is called, the state transitions to
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** PAGER_RESERVED. (Note that sqlite3PagerWrite() can only be
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** called on an outstanding page which means that the pager must
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** be in PAGER_SHARED before it transitions to PAGER_RESERVED.)
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** PAGER_RESERVED means that there is an open rollback journal.
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** The transition to PAGER_EXCLUSIVE occurs before any changes
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** are made to the database file, though writes to the rollback
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** journal occurs with just PAGER_RESERVED. After an sqlite3PagerRollback()
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** or sqlite3PagerCommitPhaseTwo(), the state can go back to PAGER_SHARED,
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** or it can stay at PAGER_EXCLUSIVE if we are in exclusive access mode.
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*/
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#define PAGER_UNLOCK 0
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#define PAGER_SHARED 1 /* same as SHARED_LOCK */
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#define PAGER_RESERVED 2 /* same as RESERVED_LOCK */
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#define PAGER_EXCLUSIVE 4 /* same as EXCLUSIVE_LOCK */
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#define PAGER_SYNCED 5
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/*
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** If the SQLITE_BUSY_RESERVED_LOCK macro is set to true at compile-time,
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** then failed attempts to get a reserved lock will invoke the busy callback.
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** This is off by default. To see why, consider the following scenario:
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**
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** Suppose thread A already has a shared lock and wants a reserved lock.
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** Thread B already has a reserved lock and wants an exclusive lock. If
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** both threads are using their busy callbacks, it might be a long time
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** be for one of the threads give up and allows the other to proceed.
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** But if the thread trying to get the reserved lock gives up quickly
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** (if it never invokes its busy callback) then the contention will be
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** resolved quickly.
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*/
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#ifndef SQLITE_BUSY_RESERVED_LOCK
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# define SQLITE_BUSY_RESERVED_LOCK 0
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#endif
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/*
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** This macro rounds values up so that if the value is an address it
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** is guaranteed to be an address that is aligned to an 8-byte boundary.
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*/
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#define FORCE_ALIGNMENT(X) (((X)+7)&~7)
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/*
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** Each in-memory image of a page begins with the following header.
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** This header is only visible to this pager module. The client
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** code that calls pager sees only the data that follows the header.
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**
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** Client code should call sqlite3PagerWrite() on a page prior to making
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** any modifications to that page. The first time sqlite3PagerWrite()
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** is called, the original page contents are written into the rollback
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** journal and PgHdr.inJournal and PgHdr.needSync are set. Later, once
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** the journal page has made it onto the disk surface, PgHdr.needSync
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** is cleared. The modified page cannot be written back into the original
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** database file until the journal pages has been synced to disk and the
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** PgHdr.needSync has been cleared.
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**
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** The PgHdr.dirty flag is set when sqlite3PagerWrite() is called and
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** is cleared again when the page content is written back to the original
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** database file.
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**
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** Details of important structure elements:
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**
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** needSync
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**
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** If this is true, this means that it is not safe to write the page
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** content to the database because the original content needed
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** for rollback has not by synced to the main rollback journal.
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** The original content may have been written to the rollback journal
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** but it has not yet been synced. So we cannot write to the database
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** file because power failure might cause the page in the journal file
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** to never reach the disk. It is as if the write to the journal file
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** does not occur until the journal file is synced.
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**
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** This flag is false if the page content exactly matches what
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** currently exists in the database file. The needSync flag is also
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** false if the original content has been written to the main rollback
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** journal and synced. If the page represents a new page that has
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** been added onto the end of the database during the current
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** transaction, the needSync flag is true until the original database
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** size in the journal header has been synced to disk.
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**
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** inJournal
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**
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** This is true if the original page has been written into the main
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** rollback journal. This is always false for new pages added to
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** the end of the database file during the current transaction.
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** And this flag says nothing about whether or not the journal
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** has been synced to disk. For pages that are in the original
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** database file, the following expression should always be true:
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**
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** inJournal = (pPager->aInJournal[(pgno-1)/8] & (1<<((pgno-1)%8))!=0
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**
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** The pPager->aInJournal[] array is only valid for the original
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** pages of the database, not new pages that are added to the end
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** of the database, so obviously the above expression cannot be
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** valid for new pages. For new pages inJournal is always 0.
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**
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** dirty
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**
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** When true, this means that the content of the page has been
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** modified and needs to be written back to the database file.
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** If false, it means that either the content of the page is
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** unchanged or else the content is unimportant and we do not
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** care whether or not it is preserved.
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**
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** alwaysRollback
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**
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** This means that the sqlite3PagerDontRollback() API should be
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** ignored for this page. The DontRollback() API attempts to say
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** that the content of the page on disk is unimportant (it is an
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** unused page on the freelist) so that it is unnecessary to
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** rollback changes to this page because the content of the page
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** can change without changing the meaning of the database. This
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** flag overrides any DontRollback() attempt. This flag is set
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** when a page that originally contained valid data is added to
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** the freelist. Later in the same transaction, this page might
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** be pulled from the freelist and reused for something different
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** and at that point the DontRollback() API will be called because
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** pages taken from the freelist do not need to be protected by
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** the rollback journal. But this flag says that the page was
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** not originally part of the freelist so that it still needs to
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** be rolled back in spite of any subsequent DontRollback() calls.
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**
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** needRead
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**
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** This flag means (when true) that the content of the page has
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** not yet been loaded from disk. The in-memory content is just
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** garbage. (Actually, we zero the content, but you should not
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** make any assumptions about the content nevertheless.) If the
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** content is needed in the future, it should be read from the
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** original database file.
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*/
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typedef struct PgHdr PgHdr;
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struct PgHdr {
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Pager *pPager; /* The pager to which this page belongs */
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Pgno pgno; /* The page number for this page */
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PgHdr *pNextHash, *pPrevHash; /* Hash collision chain for PgHdr.pgno */
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PgHdr *pNextFree, *pPrevFree; /* Freelist of pages where nRef==0 */
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PgHdr *pNextAll; /* A list of all pages */
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u8 inJournal; /* TRUE if has been written to journal */
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u8 dirty; /* TRUE if we need to write back changes */
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u8 needSync; /* Sync journal before writing this page */
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u8 alwaysRollback; /* Disable DontRollback() for this page */
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u8 needRead; /* Read content if PagerWrite() is called */
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short int nRef; /* Number of users of this page */
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PgHdr *pDirty, *pPrevDirty; /* Dirty pages */
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u32 notUsed; /* Buffer space */
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#ifdef SQLITE_CHECK_PAGES
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u32 pageHash;
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#endif
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/* pPager->pageSize bytes of page data follow this header */
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/* Pager.nExtra bytes of local data follow the page data */
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};
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/*
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** For an in-memory only database, some extra information is recorded about
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** each page so that changes can be rolled back. (Journal files are not
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** used for in-memory databases.) The following information is added to
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** the end of every EXTRA block for in-memory databases.
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**
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** This information could have been added directly to the PgHdr structure.
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** But then it would take up an extra 8 bytes of storage on every PgHdr
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** even for disk-based databases. Splitting it out saves 8 bytes. This
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** is only a savings of 0.8% but those percentages add up.
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*/
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typedef struct PgHistory PgHistory;
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struct PgHistory {
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u8 *pOrig; /* Original page text. Restore to this on a full rollback */
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u8 *pStmt; /* Text as it was at the beginning of the current statement */
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PgHdr *pNextStmt, *pPrevStmt; /* List of pages in the statement journal */
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u8 inStmt; /* TRUE if in the statement subjournal */
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};
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/*
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** A macro used for invoking the codec if there is one
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*/
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#ifdef SQLITE_HAS_CODEC
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# define CODEC1(P,D,N,X) if( P->xCodec!=0 ){ P->xCodec(P->pCodecArg,D,N,X); }
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# define CODEC2(P,D,N,X) ((char*)(P->xCodec!=0?P->xCodec(P->pCodecArg,D,N,X):D))
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#else
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# define CODEC1(P,D,N,X) /* NO-OP */
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# define CODEC2(P,D,N,X) ((char*)D)
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#endif
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/*
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** Convert a pointer to a PgHdr into a pointer to its data
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** and back again.
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*/
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#define PGHDR_TO_DATA(P) ((void*)(&(P)[1]))
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#define DATA_TO_PGHDR(D) (&((PgHdr*)(D))[-1])
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#define PGHDR_TO_EXTRA(G,P) ((void*)&((char*)(&(G)[1]))[(P)->pageSize])
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#define PGHDR_TO_HIST(P,PGR) \
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((PgHistory*)&((char*)(&(P)[1]))[(PGR)->pageSize+(PGR)->nExtra])
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/*
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** A open page cache is an instance of the following structure.
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**
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** Pager.errCode may be set to SQLITE_IOERR, SQLITE_CORRUPT, or
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** or SQLITE_FULL. Once one of the first three errors occurs, it persists
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** and is returned as the result of every major pager API call. The
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** SQLITE_FULL return code is slightly different. It persists only until the
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** next successful rollback is performed on the pager cache. Also,
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** SQLITE_FULL does not affect the sqlite3PagerGet() and sqlite3PagerLookup()
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** APIs, they may still be used successfully.
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*/
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struct Pager {
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u8 journalOpen; /* True if journal file descriptors is valid */
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u8 journalStarted; /* True if header of journal is synced */
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u8 useJournal; /* Use a rollback journal on this file */
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u8 noReadlock; /* Do not bother to obtain readlocks */
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u8 stmtOpen; /* True if the statement subjournal is open */
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u8 stmtInUse; /* True we are in a statement subtransaction */
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u8 stmtAutoopen; /* Open stmt journal when main journal is opened*/
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u8 noSync; /* Do not sync the journal if true */
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u8 fullSync; /* Do extra syncs of the journal for robustness */
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u8 full_fsync; /* Use F_FULLFSYNC when available */
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u8 state; /* PAGER_UNLOCK, _SHARED, _RESERVED, etc. */
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u8 tempFile; /* zFilename is a temporary file */
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u8 readOnly; /* True for a read-only database */
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u8 needSync; /* True if an fsync() is needed on the journal */
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u8 dirtyCache; /* True if cached pages have changed */
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u8 alwaysRollback; /* Disable DontRollback() for all pages */
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u8 memDb; /* True to inhibit all file I/O */
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u8 setMaster; /* True if a m-j name has been written to jrnl */
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u8 doNotSync; /* Boolean. While true, do not spill the cache */
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u8 exclusiveMode; /* Boolean. True if locking_mode==EXCLUSIVE */
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u8 changeCountDone; /* Set after incrementing the change-counter */
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int errCode; /* One of several kinds of errors */
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int dbSize; /* Number of pages in the file */
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int origDbSize; /* dbSize before the current change */
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int stmtSize; /* Size of database (in pages) at stmt_begin() */
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int nRec; /* Number of pages written to the journal */
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u32 cksumInit; /* Quasi-random value added to every checksum */
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int stmtNRec; /* Number of records in stmt subjournal */
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int nExtra; /* Add this many bytes to each in-memory page */
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int pageSize; /* Number of bytes in a page */
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int nPage; /* Total number of in-memory pages */
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int nRef; /* Number of in-memory pages with PgHdr.nRef>0 */
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int mxPage; /* Maximum number of pages to hold in cache */
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Pgno mxPgno; /* Maximum allowed size of the database */
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u8 *aInJournal; /* One bit for each page in the database file */
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u8 *aInStmt; /* One bit for each page in the database */
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char *zFilename; /* Name of the database file */
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char *zJournal; /* Name of the journal file */
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char *zDirectory; /* Directory hold database and journal files */
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OsFile *fd, *jfd; /* File descriptors for database and journal */
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OsFile *stfd; /* File descriptor for the statement subjournal*/
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BusyHandler *pBusyHandler; /* Pointer to sqlite.busyHandler */
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PgHdr *pFirst, *pLast; /* List of free pages */
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PgHdr *pFirstSynced; /* First free page with PgHdr.needSync==0 */
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PgHdr *pAll; /* List of all pages */
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PgHdr *pStmt; /* List of pages in the statement subjournal */
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PgHdr *pDirty; /* List of all dirty pages */
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i64 journalOff; /* Current byte offset in the journal file */
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i64 journalHdr; /* Byte offset to previous journal header */
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i64 stmtHdrOff; /* First journal header written this statement */
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i64 stmtCksum; /* cksumInit when statement was started */
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i64 stmtJSize; /* Size of journal at stmt_begin() */
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int sectorSize; /* Assumed sector size during rollback */
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#ifdef SQLITE_TEST
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int nHit, nMiss; /* Cache hits and missing */
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int nRead, nWrite; /* Database pages read/written */
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#endif
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void (*xDestructor)(DbPage*,int); /* Call this routine when freeing pages */
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void (*xReiniter)(DbPage*,int); /* Call this routine when reloading pages */
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#ifdef SQLITE_HAS_CODEC
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void *(*xCodec)(void*,void*,Pgno,int); /* Routine for en/decoding data */
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void *pCodecArg; /* First argument to xCodec() */
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#endif
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int nHash; /* Size of the pager hash table */
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PgHdr **aHash; /* Hash table to map page number to PgHdr */
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#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
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Pager *pNext; /* Linked list of pagers in this thread */
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#endif
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char *pTmpSpace; /* Pager.pageSize bytes of space for tmp use */
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char dbFileVers[16]; /* Changes whenever database file changes */
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};
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/*
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** The following global variables hold counters used for
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** testing purposes only. These variables do not exist in
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** a non-testing build. These variables are not thread-safe.
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*/
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#ifdef SQLITE_TEST
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int sqlite3_pager_readdb_count = 0; /* Number of full pages read from DB */
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int sqlite3_pager_writedb_count = 0; /* Number of full pages written to DB */
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int sqlite3_pager_writej_count = 0; /* Number of pages written to journal */
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int sqlite3_pager_pgfree_count = 0; /* Number of cache pages freed */
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# define PAGER_INCR(v) v++
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#else
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# define PAGER_INCR(v)
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#endif
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/*
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** Journal files begin with the following magic string. The data
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** was obtained from /dev/random. It is used only as a sanity check.
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**
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** Since version 2.8.0, the journal format contains additional sanity
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** checking information. If the power fails while the journal is begin
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** written, semi-random garbage data might appear in the journal
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** file after power is restored. If an attempt is then made
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** to roll the journal back, the database could be corrupted. The additional
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** sanity checking data is an attempt to discover the garbage in the
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** journal and ignore it.
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**
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** The sanity checking information for the new journal format consists
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** of a 32-bit checksum on each page of data. The checksum covers both
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** the page number and the pPager->pageSize bytes of data for the page.
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** This cksum is initialized to a 32-bit random value that appears in the
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** journal file right after the header. The random initializer is important,
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** because garbage data that appears at the end of a journal is likely
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** data that was once in other files that have now been deleted. If the
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** garbage data came from an obsolete journal file, the checksums might
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** be correct. But by initializing the checksum to random value which
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** is different for every journal, we minimize that risk.
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*/
|
|
static const unsigned char aJournalMagic[] = {
|
|
0xd9, 0xd5, 0x05, 0xf9, 0x20, 0xa1, 0x63, 0xd7,
|
|
};
|
|
|
|
/*
|
|
** The size of the header and of each page in the journal is determined
|
|
** by the following macros.
|
|
*/
|
|
#define JOURNAL_PG_SZ(pPager) ((pPager->pageSize) + 8)
|
|
|
|
/*
|
|
** The journal header size for this pager. In the future, this could be
|
|
** set to some value read from the disk controller. The important
|
|
** characteristic is that it is the same size as a disk sector.
|
|
*/
|
|
#define JOURNAL_HDR_SZ(pPager) (pPager->sectorSize)
|
|
|
|
/*
|
|
** The macro MEMDB is true if we are dealing with an in-memory database.
|
|
** We do this as a macro so that if the SQLITE_OMIT_MEMORYDB macro is set,
|
|
** the value of MEMDB will be a constant and the compiler will optimize
|
|
** out code that would never execute.
|
|
*/
|
|
#ifdef SQLITE_OMIT_MEMORYDB
|
|
# define MEMDB 0
|
|
#else
|
|
# define MEMDB pPager->memDb
|
|
#endif
|
|
|
|
/*
|
|
** Page number PAGER_MJ_PGNO is never used in an SQLite database (it is
|
|
** reserved for working around a windows/posix incompatibility). It is
|
|
** used in the journal to signify that the remainder of the journal file
|
|
** is devoted to storing a master journal name - there are no more pages to
|
|
** roll back. See comments for function writeMasterJournal() for details.
|
|
*/
|
|
/* #define PAGER_MJ_PGNO(x) (PENDING_BYTE/((x)->pageSize)) */
|
|
#define PAGER_MJ_PGNO(x) ((PENDING_BYTE/((x)->pageSize))+1)
|
|
|
|
/*
|
|
** The maximum legal page number is (2^31 - 1).
|
|
*/
|
|
#define PAGER_MAX_PGNO 2147483647
|
|
|
|
/*
|
|
** Enable reference count tracking (for debugging) here:
|
|
*/
|
|
#ifdef SQLITE_DEBUG
|
|
int pager3_refinfo_enable = 0;
|
|
static void pager_refinfo(PgHdr *p){
|
|
static int cnt = 0;
|
|
if( !pager3_refinfo_enable ) return;
|
|
sqlite3DebugPrintf(
|
|
"REFCNT: %4d addr=%p nRef=%-3d total=%d\n",
|
|
p->pgno, PGHDR_TO_DATA(p), p->nRef, p->pPager->nRef
|
|
);
|
|
cnt++; /* Something to set a breakpoint on */
|
|
}
|
|
# define REFINFO(X) pager_refinfo(X)
|
|
#else
|
|
# define REFINFO(X)
|
|
#endif
|
|
|
|
/*
|
|
** Return true if page *pPg has already been written to the statement
|
|
** journal (or statement snapshot has been created, if *pPg is part
|
|
** of an in-memory database).
|
|
*/
|
|
static int pageInStatement(PgHdr *pPg){
|
|
Pager *pPager = pPg->pPager;
|
|
if( MEMDB ){
|
|
return PGHDR_TO_HIST(pPg, pPager)->inStmt;
|
|
}else{
|
|
Pgno pgno = pPg->pgno;
|
|
u8 *a = pPager->aInStmt;
|
|
return (a && (int)pgno<=pPager->stmtSize && (a[pgno/8] & (1<<(pgno&7))));
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Change the size of the pager hash table to N. N must be a power
|
|
** of two.
|
|
*/
|
|
static void pager_resize_hash_table(Pager *pPager, int N){
|
|
PgHdr **aHash, *pPg;
|
|
assert( N>0 && (N&(N-1))==0 );
|
|
aHash = sqliteMalloc( sizeof(aHash[0])*N );
|
|
if( aHash==0 ){
|
|
/* Failure to rehash is not an error. It is only a performance hit. */
|
|
return;
|
|
}
|
|
sqliteFree(pPager->aHash);
|
|
pPager->nHash = N;
|
|
pPager->aHash = aHash;
|
|
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
|
|
int h;
|
|
if( pPg->pgno==0 ){
|
|
assert( pPg->pNextHash==0 && pPg->pPrevHash==0 );
|
|
continue;
|
|
}
|
|
h = pPg->pgno & (N-1);
|
|
pPg->pNextHash = aHash[h];
|
|
if( aHash[h] ){
|
|
aHash[h]->pPrevHash = pPg;
|
|
}
|
|
aHash[h] = pPg;
|
|
pPg->pPrevHash = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Read a 32-bit integer from the given file descriptor. Store the integer
|
|
** that is read in *pRes. Return SQLITE_OK if everything worked, or an
|
|
** error code is something goes wrong.
|
|
**
|
|
** All values are stored on disk as big-endian.
|
|
*/
|
|
static int read32bits(OsFile *fd, u32 *pRes){
|
|
unsigned char ac[4];
|
|
int rc = sqlite3OsRead(fd, ac, sizeof(ac));
|
|
if( rc==SQLITE_OK ){
|
|
*pRes = sqlite3Get4byte(ac);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Write a 32-bit integer into a string buffer in big-endian byte order.
|
|
*/
|
|
#define put32bits(A,B) sqlite3Put4byte((u8*)A,B)
|
|
|
|
/*
|
|
** Write a 32-bit integer into the given file descriptor. Return SQLITE_OK
|
|
** on success or an error code is something goes wrong.
|
|
*/
|
|
static int write32bits(OsFile *fd, u32 val){
|
|
char ac[4];
|
|
put32bits(ac, val);
|
|
return sqlite3OsWrite(fd, ac, 4);
|
|
}
|
|
|
|
/*
|
|
** This function should be called when an error occurs within the pager
|
|
** code. The first argument is a pointer to the pager structure, the
|
|
** second the error-code about to be returned by a pager API function.
|
|
** The value returned is a copy of the second argument to this function.
|
|
**
|
|
** If the second argument is SQLITE_IOERR, SQLITE_CORRUPT, or SQLITE_FULL
|
|
** the error becomes persistent. All subsequent API calls on this Pager
|
|
** will immediately return the same error code.
|
|
*/
|
|
static int pager_error(Pager *pPager, int rc){
|
|
int rc2 = rc & 0xff;
|
|
assert( pPager->errCode==SQLITE_FULL || pPager->errCode==SQLITE_OK );
|
|
if(
|
|
rc2==SQLITE_FULL ||
|
|
rc2==SQLITE_IOERR ||
|
|
rc2==SQLITE_CORRUPT
|
|
){
|
|
pPager->errCode = rc;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
|
|
** on the cache using a hash function. This is used for testing
|
|
** and debugging only.
|
|
*/
|
|
#ifdef SQLITE_CHECK_PAGES
|
|
/*
|
|
** Return a 32-bit hash of the page data for pPage.
|
|
*/
|
|
static u32 pager_datahash(int nByte, unsigned char *pData){
|
|
u32 hash = 0;
|
|
int i;
|
|
for(i=0; i<nByte; i++){
|
|
hash = (hash*1039) + pData[i];
|
|
}
|
|
return hash;
|
|
}
|
|
static u32 pager_pagehash(PgHdr *pPage){
|
|
return pager_datahash(pPage->pPager->pageSize,
|
|
(unsigned char *)PGHDR_TO_DATA(pPage));
|
|
}
|
|
|
|
/*
|
|
** The CHECK_PAGE macro takes a PgHdr* as an argument. If SQLITE_CHECK_PAGES
|
|
** is defined, and NDEBUG is not defined, an assert() statement checks
|
|
** that the page is either dirty or still matches the calculated page-hash.
|
|
*/
|
|
#define CHECK_PAGE(x) checkPage(x)
|
|
static void checkPage(PgHdr *pPg){
|
|
Pager *pPager = pPg->pPager;
|
|
assert( !pPg->pageHash || pPager->errCode || MEMDB || pPg->dirty ||
|
|
pPg->pageHash==pager_pagehash(pPg) );
|
|
}
|
|
|
|
#else
|
|
#define pager_datahash(X,Y) 0
|
|
#define pager_pagehash(X) 0
|
|
#define CHECK_PAGE(x)
|
|
#endif
|
|
|
|
/*
|
|
** When this is called the journal file for pager pPager must be open.
|
|
** The master journal file name is read from the end of the file and
|
|
** written into memory obtained from sqliteMalloc(). *pzMaster is
|
|
** set to point at the memory and SQLITE_OK returned. The caller must
|
|
** sqliteFree() *pzMaster.
|
|
**
|
|
** If no master journal file name is present *pzMaster is set to 0 and
|
|
** SQLITE_OK returned.
|
|
*/
|
|
static int readMasterJournal(OsFile *pJrnl, char **pzMaster){
|
|
int rc;
|
|
u32 len;
|
|
i64 szJ;
|
|
u32 cksum;
|
|
int i;
|
|
unsigned char aMagic[8]; /* A buffer to hold the magic header */
|
|
|
|
*pzMaster = 0;
|
|
|
|
rc = sqlite3OsFileSize(pJrnl, &szJ);
|
|
if( rc!=SQLITE_OK || szJ<16 ) return rc;
|
|
|
|
rc = sqlite3OsSeek(pJrnl, szJ-16);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
rc = read32bits(pJrnl, &len);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
rc = read32bits(pJrnl, &cksum);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
rc = sqlite3OsRead(pJrnl, aMagic, 8);
|
|
if( rc!=SQLITE_OK || memcmp(aMagic, aJournalMagic, 8) ) return rc;
|
|
|
|
rc = sqlite3OsSeek(pJrnl, szJ-16-len);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
*pzMaster = (char *)sqliteMalloc(len+1);
|
|
if( !*pzMaster ){
|
|
return SQLITE_NOMEM;
|
|
}
|
|
rc = sqlite3OsRead(pJrnl, *pzMaster, len);
|
|
if( rc!=SQLITE_OK ){
|
|
sqliteFree(*pzMaster);
|
|
*pzMaster = 0;
|
|
return rc;
|
|
}
|
|
|
|
/* See if the checksum matches the master journal name */
|
|
for(i=0; i<len; i++){
|
|
cksum -= (*pzMaster)[i];
|
|
}
|
|
if( cksum ){
|
|
/* If the checksum doesn't add up, then one or more of the disk sectors
|
|
** containing the master journal filename is corrupted. This means
|
|
** definitely roll back, so just return SQLITE_OK and report a (nul)
|
|
** master-journal filename.
|
|
*/
|
|
sqliteFree(*pzMaster);
|
|
*pzMaster = 0;
|
|
}else{
|
|
(*pzMaster)[len] = '\0';
|
|
}
|
|
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Seek the journal file descriptor to the next sector boundary where a
|
|
** journal header may be read or written. Pager.journalOff is updated with
|
|
** the new seek offset.
|
|
**
|
|
** i.e for a sector size of 512:
|
|
**
|
|
** Input Offset Output Offset
|
|
** ---------------------------------------
|
|
** 0 0
|
|
** 512 512
|
|
** 100 512
|
|
** 2000 2048
|
|
**
|
|
*/
|
|
static int seekJournalHdr(Pager *pPager){
|
|
i64 offset = 0;
|
|
i64 c = pPager->journalOff;
|
|
if( c ){
|
|
offset = ((c-1)/JOURNAL_HDR_SZ(pPager) + 1) * JOURNAL_HDR_SZ(pPager);
|
|
}
|
|
assert( offset%JOURNAL_HDR_SZ(pPager)==0 );
|
|
assert( offset>=c );
|
|
assert( (offset-c)<JOURNAL_HDR_SZ(pPager) );
|
|
pPager->journalOff = offset;
|
|
return sqlite3OsSeek(pPager->jfd, pPager->journalOff);
|
|
}
|
|
|
|
/*
|
|
** The journal file must be open when this routine is called. A journal
|
|
** header (JOURNAL_HDR_SZ bytes) is written into the journal file at the
|
|
** current location.
|
|
**
|
|
** The format for the journal header is as follows:
|
|
** - 8 bytes: Magic identifying journal format.
|
|
** - 4 bytes: Number of records in journal, or -1 no-sync mode is on.
|
|
** - 4 bytes: Random number used for page hash.
|
|
** - 4 bytes: Initial database page count.
|
|
** - 4 bytes: Sector size used by the process that wrote this journal.
|
|
**
|
|
** Followed by (JOURNAL_HDR_SZ - 24) bytes of unused space.
|
|
*/
|
|
static int writeJournalHdr(Pager *pPager){
|
|
char zHeader[sizeof(aJournalMagic)+16];
|
|
int rc;
|
|
|
|
if( pPager->stmtHdrOff==0 ){
|
|
pPager->stmtHdrOff = pPager->journalOff;
|
|
}
|
|
|
|
rc = seekJournalHdr(pPager);
|
|
if( rc ) return rc;
|
|
|
|
pPager->journalHdr = pPager->journalOff;
|
|
pPager->journalOff += JOURNAL_HDR_SZ(pPager);
|
|
|
|
/* FIX ME:
|
|
**
|
|
** Possibly for a pager not in no-sync mode, the journal magic should not
|
|
** be written until nRec is filled in as part of next syncJournal().
|
|
**
|
|
** Actually maybe the whole journal header should be delayed until that
|
|
** point. Think about this.
|
|
*/
|
|
memcpy(zHeader, aJournalMagic, sizeof(aJournalMagic));
|
|
/* The nRec Field. 0xFFFFFFFF for no-sync journals. */
|
|
put32bits(&zHeader[sizeof(aJournalMagic)], pPager->noSync ? 0xffffffff : 0);
|
|
/* The random check-hash initialiser */
|
|
sqlite3Randomness(sizeof(pPager->cksumInit), &pPager->cksumInit);
|
|
put32bits(&zHeader[sizeof(aJournalMagic)+4], pPager->cksumInit);
|
|
/* The initial database size */
|
|
put32bits(&zHeader[sizeof(aJournalMagic)+8], pPager->dbSize);
|
|
/* The assumed sector size for this process */
|
|
put32bits(&zHeader[sizeof(aJournalMagic)+12], pPager->sectorSize);
|
|
IOTRACE(("JHDR %p %lld %d\n", pPager, pPager->journalHdr, sizeof(zHeader)))
|
|
rc = sqlite3OsWrite(pPager->jfd, zHeader, sizeof(zHeader));
|
|
|
|
/* The journal header has been written successfully. Seek the journal
|
|
** file descriptor to the end of the journal header sector.
|
|
*/
|
|
if( rc==SQLITE_OK ){
|
|
IOTRACE(("JTAIL %p %lld\n", pPager, pPager->journalOff-1))
|
|
rc = sqlite3OsSeek(pPager->jfd, pPager->journalOff-1);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3OsWrite(pPager->jfd, "\000", 1);
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** The journal file must be open when this is called. A journal header file
|
|
** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
|
|
** file. See comments above function writeJournalHdr() for a description of
|
|
** the journal header format.
|
|
**
|
|
** If the header is read successfully, *nRec is set to the number of
|
|
** page records following this header and *dbSize is set to the size of the
|
|
** database before the transaction began, in pages. Also, pPager->cksumInit
|
|
** is set to the value read from the journal header. SQLITE_OK is returned
|
|
** in this case.
|
|
**
|
|
** If the journal header file appears to be corrupted, SQLITE_DONE is
|
|
** returned and *nRec and *dbSize are not set. If JOURNAL_HDR_SZ bytes
|
|
** cannot be read from the journal file an error code is returned.
|
|
*/
|
|
static int readJournalHdr(
|
|
Pager *pPager,
|
|
i64 journalSize,
|
|
u32 *pNRec,
|
|
u32 *pDbSize
|
|
){
|
|
int rc;
|
|
unsigned char aMagic[8]; /* A buffer to hold the magic header */
|
|
|
|
rc = seekJournalHdr(pPager);
|
|
if( rc ) return rc;
|
|
|
|
if( pPager->journalOff+JOURNAL_HDR_SZ(pPager) > journalSize ){
|
|
return SQLITE_DONE;
|
|
}
|
|
|
|
rc = sqlite3OsRead(pPager->jfd, aMagic, sizeof(aMagic));
|
|
if( rc ) return rc;
|
|
|
|
if( memcmp(aMagic, aJournalMagic, sizeof(aMagic))!=0 ){
|
|
return SQLITE_DONE;
|
|
}
|
|
|
|
rc = read32bits(pPager->jfd, pNRec);
|
|
if( rc ) return rc;
|
|
|
|
rc = read32bits(pPager->jfd, &pPager->cksumInit);
|
|
if( rc ) return rc;
|
|
|
|
rc = read32bits(pPager->jfd, pDbSize);
|
|
if( rc ) return rc;
|
|
|
|
/* Update the assumed sector-size to match the value used by
|
|
** the process that created this journal. If this journal was
|
|
** created by a process other than this one, then this routine
|
|
** is being called from within pager_playback(). The local value
|
|
** of Pager.sectorSize is restored at the end of that routine.
|
|
*/
|
|
rc = read32bits(pPager->jfd, (u32 *)&pPager->sectorSize);
|
|
if( rc ) return rc;
|
|
|
|
pPager->journalOff += JOURNAL_HDR_SZ(pPager);
|
|
rc = sqlite3OsSeek(pPager->jfd, pPager->journalOff);
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** Write the supplied master journal name into the journal file for pager
|
|
** pPager at the current location. The master journal name must be the last
|
|
** thing written to a journal file. If the pager is in full-sync mode, the
|
|
** journal file descriptor is advanced to the next sector boundary before
|
|
** anything is written. The format is:
|
|
**
|
|
** + 4 bytes: PAGER_MJ_PGNO.
|
|
** + N bytes: length of master journal name.
|
|
** + 4 bytes: N
|
|
** + 4 bytes: Master journal name checksum.
|
|
** + 8 bytes: aJournalMagic[].
|
|
**
|
|
** The master journal page checksum is the sum of the bytes in the master
|
|
** journal name.
|
|
**
|
|
** If zMaster is a NULL pointer (occurs for a single database transaction),
|
|
** this call is a no-op.
|
|
*/
|
|
static int writeMasterJournal(Pager *pPager, const char *zMaster){
|
|
int rc;
|
|
int len;
|
|
int i;
|
|
u32 cksum = 0;
|
|
char zBuf[sizeof(aJournalMagic)+2*4];
|
|
|
|
if( !zMaster || pPager->setMaster) return SQLITE_OK;
|
|
pPager->setMaster = 1;
|
|
|
|
len = strlen(zMaster);
|
|
for(i=0; i<len; i++){
|
|
cksum += zMaster[i];
|
|
}
|
|
|
|
/* If in full-sync mode, advance to the next disk sector before writing
|
|
** the master journal name. This is in case the previous page written to
|
|
** the journal has already been synced.
|
|
*/
|
|
if( pPager->fullSync ){
|
|
rc = seekJournalHdr(pPager);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
}
|
|
pPager->journalOff += (len+20);
|
|
|
|
rc = write32bits(pPager->jfd, PAGER_MJ_PGNO(pPager));
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
rc = sqlite3OsWrite(pPager->jfd, zMaster, len);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
put32bits(zBuf, len);
|
|
put32bits(&zBuf[4], cksum);
|
|
memcpy(&zBuf[8], aJournalMagic, sizeof(aJournalMagic));
|
|
rc = sqlite3OsWrite(pPager->jfd, zBuf, 8+sizeof(aJournalMagic));
|
|
pPager->needSync = !pPager->noSync;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Add or remove a page from the list of all pages that are in the
|
|
** statement journal.
|
|
**
|
|
** The Pager keeps a separate list of pages that are currently in
|
|
** the statement journal. This helps the sqlite3PagerStmtCommit()
|
|
** routine run MUCH faster for the common case where there are many
|
|
** pages in memory but only a few are in the statement journal.
|
|
*/
|
|
static void page_add_to_stmt_list(PgHdr *pPg){
|
|
Pager *pPager = pPg->pPager;
|
|
PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
|
|
assert( MEMDB );
|
|
if( !pHist->inStmt ){
|
|
assert( pHist->pPrevStmt==0 && pHist->pNextStmt==0 );
|
|
if( pPager->pStmt ){
|
|
PGHDR_TO_HIST(pPager->pStmt, pPager)->pPrevStmt = pPg;
|
|
}
|
|
pHist->pNextStmt = pPager->pStmt;
|
|
pPager->pStmt = pPg;
|
|
pHist->inStmt = 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Find a page in the hash table given its page number. Return
|
|
** a pointer to the page or NULL if not found.
|
|
*/
|
|
static PgHdr *pager_lookup(Pager *pPager, Pgno pgno){
|
|
PgHdr *p;
|
|
if( pPager->aHash==0 ) return 0;
|
|
p = pPager->aHash[pgno & (pPager->nHash-1)];
|
|
while( p && p->pgno!=pgno ){
|
|
p = p->pNextHash;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
/*
|
|
** Unlock the database file.
|
|
*/
|
|
static void pager_unlock(Pager *pPager){
|
|
if( !pPager->exclusiveMode ){
|
|
if( !MEMDB ){
|
|
sqlite3OsUnlock(pPager->fd, NO_LOCK);
|
|
pPager->dbSize = -1;
|
|
IOTRACE(("UNLOCK %p\n", pPager))
|
|
}
|
|
pPager->state = PAGER_UNLOCK;
|
|
pPager->changeCountDone = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Execute a rollback if a transaction is active and unlock the
|
|
** database file. This is a no-op if the pager has already entered
|
|
** the error-state.
|
|
*/
|
|
static void pagerUnlockAndRollback(Pager *p){
|
|
if( p->errCode ) return;
|
|
assert( p->state>=PAGER_RESERVED || p->journalOpen==0 );
|
|
if( p->state>=PAGER_RESERVED ){
|
|
sqlite3PagerRollback(p);
|
|
}
|
|
pager_unlock(p);
|
|
assert( p->errCode || !p->journalOpen || (p->exclusiveMode&&!p->journalOff) );
|
|
assert( p->errCode || !p->stmtOpen || p->exclusiveMode );
|
|
}
|
|
|
|
|
|
/*
|
|
** Clear the in-memory cache. This routine
|
|
** sets the state of the pager back to what it was when it was first
|
|
** opened. Any outstanding pages are invalidated and subsequent attempts
|
|
** to access those pages will likely result in a coredump.
|
|
*/
|
|
static void pager_reset(Pager *pPager){
|
|
PgHdr *pPg, *pNext;
|
|
if( pPager->errCode ) return;
|
|
for(pPg=pPager->pAll; pPg; pPg=pNext){
|
|
IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
|
|
PAGER_INCR(sqlite3_pager_pgfree_count);
|
|
pNext = pPg->pNextAll;
|
|
sqliteFree(pPg);
|
|
}
|
|
pPager->pStmt = 0;
|
|
pPager->pFirst = 0;
|
|
pPager->pFirstSynced = 0;
|
|
pPager->pLast = 0;
|
|
pPager->pAll = 0;
|
|
pPager->nHash = 0;
|
|
sqliteFree(pPager->aHash);
|
|
pPager->nPage = 0;
|
|
pPager->aHash = 0;
|
|
pPager->nRef = 0;
|
|
}
|
|
|
|
/*
|
|
** This routine ends a transaction. A transaction is ended by either
|
|
** a COMMIT or a ROLLBACK.
|
|
**
|
|
** When this routine is called, the pager has the journal file open and
|
|
** a RESERVED or EXCLUSIVE lock on the database. This routine will release
|
|
** the database lock and acquires a SHARED lock in its place if that is
|
|
** the appropriate thing to do. Release locks usually is appropriate,
|
|
** unless we are in exclusive access mode or unless this is a
|
|
** COMMIT AND BEGIN or ROLLBACK AND BEGIN operation.
|
|
**
|
|
** The journal file is either deleted or truncated.
|
|
**
|
|
** TODO: Consider keeping the journal file open for temporary databases.
|
|
** This might give a performance improvement on windows where opening
|
|
** a file is an expensive operation.
|
|
*/
|
|
static int pager_end_transaction(Pager *pPager){
|
|
PgHdr *pPg;
|
|
int rc = SQLITE_OK;
|
|
int rc2 = SQLITE_OK;
|
|
assert( !MEMDB );
|
|
if( pPager->state<PAGER_RESERVED ){
|
|
return SQLITE_OK;
|
|
}
|
|
sqlite3PagerStmtCommit(pPager);
|
|
if( pPager->stmtOpen && !pPager->exclusiveMode ){
|
|
sqlite3OsClose(&pPager->stfd);
|
|
pPager->stmtOpen = 0;
|
|
}
|
|
if( pPager->journalOpen ){
|
|
if( pPager->exclusiveMode
|
|
&& (rc = sqlite3OsTruncate(pPager->jfd, 0))==SQLITE_OK ){;
|
|
sqlite3OsSeek(pPager->jfd, 0);
|
|
pPager->journalOff = 0;
|
|
pPager->journalStarted = 0;
|
|
}else{
|
|
sqlite3OsClose(&pPager->jfd);
|
|
pPager->journalOpen = 0;
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3OsDelete(pPager->zJournal);
|
|
}
|
|
}
|
|
sqliteFree( pPager->aInJournal );
|
|
pPager->aInJournal = 0;
|
|
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
|
|
pPg->inJournal = 0;
|
|
pPg->dirty = 0;
|
|
pPg->needSync = 0;
|
|
pPg->alwaysRollback = 0;
|
|
#ifdef SQLITE_CHECK_PAGES
|
|
pPg->pageHash = pager_pagehash(pPg);
|
|
#endif
|
|
}
|
|
pPager->pDirty = 0;
|
|
pPager->dirtyCache = 0;
|
|
pPager->nRec = 0;
|
|
}else{
|
|
assert( pPager->aInJournal==0 );
|
|
assert( pPager->dirtyCache==0 || pPager->useJournal==0 );
|
|
}
|
|
|
|
if( !pPager->exclusiveMode ){
|
|
rc2 = sqlite3OsUnlock(pPager->fd, SHARED_LOCK);
|
|
pPager->state = PAGER_SHARED;
|
|
}else if( pPager->state==PAGER_SYNCED ){
|
|
pPager->state = PAGER_EXCLUSIVE;
|
|
}
|
|
pPager->origDbSize = 0;
|
|
pPager->setMaster = 0;
|
|
pPager->needSync = 0;
|
|
pPager->pFirstSynced = pPager->pFirst;
|
|
pPager->dbSize = -1;
|
|
|
|
return (rc==SQLITE_OK?rc2:rc);
|
|
}
|
|
|
|
/*
|
|
** Compute and return a checksum for the page of data.
|
|
**
|
|
** This is not a real checksum. It is really just the sum of the
|
|
** random initial value and the page number. We experimented with
|
|
** a checksum of the entire data, but that was found to be too slow.
|
|
**
|
|
** Note that the page number is stored at the beginning of data and
|
|
** the checksum is stored at the end. This is important. If journal
|
|
** corruption occurs due to a power failure, the most likely scenario
|
|
** is that one end or the other of the record will be changed. It is
|
|
** much less likely that the two ends of the journal record will be
|
|
** correct and the middle be corrupt. Thus, this "checksum" scheme,
|
|
** though fast and simple, catches the mostly likely kind of corruption.
|
|
**
|
|
** FIX ME: Consider adding every 200th (or so) byte of the data to the
|
|
** checksum. That way if a single page spans 3 or more disk sectors and
|
|
** only the middle sector is corrupt, we will still have a reasonable
|
|
** chance of failing the checksum and thus detecting the problem.
|
|
*/
|
|
static u32 pager_cksum(Pager *pPager, const u8 *aData){
|
|
u32 cksum = pPager->cksumInit;
|
|
int i = pPager->pageSize-200;
|
|
while( i>0 ){
|
|
cksum += aData[i];
|
|
i -= 200;
|
|
}
|
|
return cksum;
|
|
}
|
|
|
|
/* Forward declaration */
|
|
static void makeClean(PgHdr*);
|
|
|
|
/*
|
|
** Read a single page from the journal file opened on file descriptor
|
|
** jfd. Playback this one page.
|
|
**
|
|
** If useCksum==0 it means this journal does not use checksums. Checksums
|
|
** are not used in statement journals because statement journals do not
|
|
** need to survive power failures.
|
|
*/
|
|
static int pager_playback_one_page(Pager *pPager, OsFile *jfd, int useCksum){
|
|
int rc;
|
|
PgHdr *pPg; /* An existing page in the cache */
|
|
Pgno pgno; /* The page number of a page in journal */
|
|
u32 cksum; /* Checksum used for sanity checking */
|
|
u8 *aData = (u8 *)pPager->pTmpSpace; /* Temp storage for a page */
|
|
|
|
/* useCksum should be true for the main journal and false for
|
|
** statement journals. Verify that this is always the case
|
|
*/
|
|
assert( jfd == (useCksum ? pPager->jfd : pPager->stfd) );
|
|
assert( aData );
|
|
|
|
rc = read32bits(jfd, &pgno);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
rc = sqlite3OsRead(jfd, aData, pPager->pageSize);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
pPager->journalOff += pPager->pageSize + 4;
|
|
|
|
/* Sanity checking on the page. This is more important that I originally
|
|
** thought. If a power failure occurs while the journal is being written,
|
|
** it could cause invalid data to be written into the journal. We need to
|
|
** detect this invalid data (with high probability) and ignore it.
|
|
*/
|
|
if( pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
|
|
return SQLITE_DONE;
|
|
}
|
|
if( pgno>(unsigned)pPager->dbSize ){
|
|
return SQLITE_OK;
|
|
}
|
|
if( useCksum ){
|
|
rc = read32bits(jfd, &cksum);
|
|
if( rc ) return rc;
|
|
pPager->journalOff += 4;
|
|
if( pager_cksum(pPager, aData)!=cksum ){
|
|
return SQLITE_DONE;
|
|
}
|
|
}
|
|
|
|
assert( pPager->state==PAGER_RESERVED || pPager->state>=PAGER_EXCLUSIVE );
|
|
|
|
/* If the pager is in RESERVED state, then there must be a copy of this
|
|
** page in the pager cache. In this case just update the pager cache,
|
|
** not the database file. The page is left marked dirty in this case.
|
|
**
|
|
** An exception to the above rule: If the database is in no-sync mode
|
|
** and a page is moved during an incremental vacuum then the page may
|
|
** not be in the pager cache. Later: if a malloc() or IO error occurs
|
|
** during a Movepage() call, then the page may not be in the cache
|
|
** either. So the condition described in the above paragraph is not
|
|
** assert()able.
|
|
**
|
|
** If in EXCLUSIVE state, then we update the pager cache if it exists
|
|
** and the main file. The page is then marked not dirty.
|
|
**
|
|
** Ticket #1171: The statement journal might contain page content that is
|
|
** different from the page content at the start of the transaction.
|
|
** This occurs when a page is changed prior to the start of a statement
|
|
** then changed again within the statement. When rolling back such a
|
|
** statement we must not write to the original database unless we know
|
|
** for certain that original page contents are synced into the main rollback
|
|
** journal. Otherwise, a power loss might leave modified data in the
|
|
** database file without an entry in the rollback journal that can
|
|
** restore the database to its original form. Two conditions must be
|
|
** met before writing to the database files. (1) the database must be
|
|
** locked. (2) we know that the original page content is fully synced
|
|
** in the main journal either because the page is not in cache or else
|
|
** the page is marked as needSync==0.
|
|
*/
|
|
pPg = pager_lookup(pPager, pgno);
|
|
PAGERTRACE4("PLAYBACK %d page %d hash(%08x)\n",
|
|
PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, aData));
|
|
if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
|
|
rc = sqlite3OsSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3OsWrite(pPager->fd, aData, pPager->pageSize);
|
|
}
|
|
if( pPg ){
|
|
makeClean(pPg);
|
|
}
|
|
}
|
|
if( pPg ){
|
|
/* No page should ever be explicitly rolled back that is in use, except
|
|
** for page 1 which is held in use in order to keep the lock on the
|
|
** database active. However such a page may be rolled back as a result
|
|
** of an internal error resulting in an automatic call to
|
|
** sqlite3PagerRollback().
|
|
*/
|
|
void *pData;
|
|
/* assert( pPg->nRef==0 || pPg->pgno==1 ); */
|
|
pData = PGHDR_TO_DATA(pPg);
|
|
memcpy(pData, aData, pPager->pageSize);
|
|
if( pPager->xReiniter ){
|
|
pPager->xReiniter(pPg, pPager->pageSize);
|
|
}
|
|
#ifdef SQLITE_CHECK_PAGES
|
|
pPg->pageHash = pager_pagehash(pPg);
|
|
#endif
|
|
/* If this was page 1, then restore the value of Pager.dbFileVers.
|
|
** Do this before any decoding. */
|
|
if( pgno==1 ){
|
|
memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
|
|
}
|
|
|
|
/* Decode the page just read from disk */
|
|
CODEC1(pPager, pData, pPg->pgno, 3);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Parameter zMaster is the name of a master journal file. A single journal
|
|
** file that referred to the master journal file has just been rolled back.
|
|
** This routine checks if it is possible to delete the master journal file,
|
|
** and does so if it is.
|
|
**
|
|
** The master journal file contains the names of all child journals.
|
|
** To tell if a master journal can be deleted, check to each of the
|
|
** children. If all children are either missing or do not refer to
|
|
** a different master journal, then this master journal can be deleted.
|
|
*/
|
|
static int pager_delmaster(const char *zMaster){
|
|
int rc;
|
|
int master_open = 0;
|
|
OsFile *master = 0;
|
|
char *zMasterJournal = 0; /* Contents of master journal file */
|
|
i64 nMasterJournal; /* Size of master journal file */
|
|
|
|
/* Open the master journal file exclusively in case some other process
|
|
** is running this routine also. Not that it makes too much difference.
|
|
*/
|
|
rc = sqlite3OsOpenReadOnly(zMaster, &master);
|
|
assert( rc!=SQLITE_OK || master );
|
|
if( rc!=SQLITE_OK ) goto delmaster_out;
|
|
master_open = 1;
|
|
rc = sqlite3OsFileSize(master, &nMasterJournal);
|
|
if( rc!=SQLITE_OK ) goto delmaster_out;
|
|
|
|
if( nMasterJournal>0 ){
|
|
char *zJournal;
|
|
char *zMasterPtr = 0;
|
|
|
|
/* Load the entire master journal file into space obtained from
|
|
** sqliteMalloc() and pointed to by zMasterJournal.
|
|
*/
|
|
zMasterJournal = (char *)sqliteMalloc(nMasterJournal);
|
|
if( !zMasterJournal ){
|
|
rc = SQLITE_NOMEM;
|
|
goto delmaster_out;
|
|
}
|
|
rc = sqlite3OsRead(master, zMasterJournal, nMasterJournal);
|
|
if( rc!=SQLITE_OK ) goto delmaster_out;
|
|
|
|
zJournal = zMasterJournal;
|
|
while( (zJournal-zMasterJournal)<nMasterJournal ){
|
|
if( sqlite3OsFileExists(zJournal) ){
|
|
/* One of the journals pointed to by the master journal exists.
|
|
** Open it and check if it points at the master journal. If
|
|
** so, return without deleting the master journal file.
|
|
*/
|
|
OsFile *journal = 0;
|
|
int c;
|
|
|
|
rc = sqlite3OsOpenReadOnly(zJournal, &journal);
|
|
assert( rc!=SQLITE_OK || journal );
|
|
if( rc!=SQLITE_OK ){
|
|
goto delmaster_out;
|
|
}
|
|
|
|
rc = readMasterJournal(journal, &zMasterPtr);
|
|
sqlite3OsClose(&journal);
|
|
if( rc!=SQLITE_OK ){
|
|
goto delmaster_out;
|
|
}
|
|
|
|
c = zMasterPtr!=0 && strcmp(zMasterPtr, zMaster)==0;
|
|
sqliteFree(zMasterPtr);
|
|
if( c ){
|
|
/* We have a match. Do not delete the master journal file. */
|
|
goto delmaster_out;
|
|
}
|
|
}
|
|
zJournal += (strlen(zJournal)+1);
|
|
}
|
|
}
|
|
|
|
rc = sqlite3OsDelete(zMaster);
|
|
|
|
delmaster_out:
|
|
if( zMasterJournal ){
|
|
sqliteFree(zMasterJournal);
|
|
}
|
|
if( master_open ){
|
|
sqlite3OsClose(&master);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
|
|
static void pager_truncate_cache(Pager *pPager);
|
|
|
|
/*
|
|
** Truncate the main file of the given pager to the number of pages
|
|
** indicated. Also truncate the cached representation of the file.
|
|
*/
|
|
static int pager_truncate(Pager *pPager, int nPage){
|
|
int rc = SQLITE_OK;
|
|
if( pPager->state>=PAGER_EXCLUSIVE ){
|
|
rc = sqlite3OsTruncate(pPager->fd, pPager->pageSize*(i64)nPage);
|
|
}
|
|
if( rc==SQLITE_OK ){
|
|
pPager->dbSize = nPage;
|
|
pager_truncate_cache(pPager);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Set the sectorSize for the given pager.
|
|
**
|
|
** The sector size is the larger of the sector size reported
|
|
** by sqlite3OsSectorSize() and the pageSize.
|
|
*/
|
|
static void setSectorSize(Pager *pPager){
|
|
pPager->sectorSize = sqlite3OsSectorSize(pPager->fd);
|
|
if( pPager->sectorSize<pPager->pageSize ){
|
|
pPager->sectorSize = pPager->pageSize;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Playback the journal and thus restore the database file to
|
|
** the state it was in before we started making changes.
|
|
**
|
|
** The journal file format is as follows:
|
|
**
|
|
** (1) 8 byte prefix. A copy of aJournalMagic[].
|
|
** (2) 4 byte big-endian integer which is the number of valid page records
|
|
** in the journal. If this value is 0xffffffff, then compute the
|
|
** number of page records from the journal size.
|
|
** (3) 4 byte big-endian integer which is the initial value for the
|
|
** sanity checksum.
|
|
** (4) 4 byte integer which is the number of pages to truncate the
|
|
** database to during a rollback.
|
|
** (5) 4 byte integer which is the number of bytes in the master journal
|
|
** name. The value may be zero (indicate that there is no master
|
|
** journal.)
|
|
** (6) N bytes of the master journal name. The name will be nul-terminated
|
|
** and might be shorter than the value read from (5). If the first byte
|
|
** of the name is \000 then there is no master journal. The master
|
|
** journal name is stored in UTF-8.
|
|
** (7) Zero or more pages instances, each as follows:
|
|
** + 4 byte page number.
|
|
** + pPager->pageSize bytes of data.
|
|
** + 4 byte checksum
|
|
**
|
|
** When we speak of the journal header, we mean the first 6 items above.
|
|
** Each entry in the journal is an instance of the 7th item.
|
|
**
|
|
** Call the value from the second bullet "nRec". nRec is the number of
|
|
** valid page entries in the journal. In most cases, you can compute the
|
|
** value of nRec from the size of the journal file. But if a power
|
|
** failure occurred while the journal was being written, it could be the
|
|
** case that the size of the journal file had already been increased but
|
|
** the extra entries had not yet made it safely to disk. In such a case,
|
|
** the value of nRec computed from the file size would be too large. For
|
|
** that reason, we always use the nRec value in the header.
|
|
**
|
|
** If the nRec value is 0xffffffff it means that nRec should be computed
|
|
** from the file size. This value is used when the user selects the
|
|
** no-sync option for the journal. A power failure could lead to corruption
|
|
** in this case. But for things like temporary table (which will be
|
|
** deleted when the power is restored) we don't care.
|
|
**
|
|
** If the file opened as the journal file is not a well-formed
|
|
** journal file then all pages up to the first corrupted page are rolled
|
|
** back (or no pages if the journal header is corrupted). The journal file
|
|
** is then deleted and SQLITE_OK returned, just as if no corruption had
|
|
** been encountered.
|
|
**
|
|
** If an I/O or malloc() error occurs, the journal-file is not deleted
|
|
** and an error code is returned.
|
|
*/
|
|
static int pager_playback(Pager *pPager, int isHot){
|
|
i64 szJ; /* Size of the journal file in bytes */
|
|
u32 nRec; /* Number of Records in the journal */
|
|
int i; /* Loop counter */
|
|
Pgno mxPg = 0; /* Size of the original file in pages */
|
|
int rc; /* Result code of a subroutine */
|
|
char *zMaster = 0; /* Name of master journal file if any */
|
|
|
|
/* Figure out how many records are in the journal. Abort early if
|
|
** the journal is empty.
|
|
*/
|
|
assert( pPager->journalOpen );
|
|
rc = sqlite3OsFileSize(pPager->jfd, &szJ);
|
|
if( rc!=SQLITE_OK || szJ==0 ){
|
|
goto end_playback;
|
|
}
|
|
|
|
/* Read the master journal name from the journal, if it is present.
|
|
** If a master journal file name is specified, but the file is not
|
|
** present on disk, then the journal is not hot and does not need to be
|
|
** played back.
|
|
*/
|
|
rc = readMasterJournal(pPager->jfd, &zMaster);
|
|
assert( rc!=SQLITE_DONE );
|
|
if( rc!=SQLITE_OK || (zMaster && !sqlite3OsFileExists(zMaster)) ){
|
|
sqliteFree(zMaster);
|
|
zMaster = 0;
|
|
if( rc==SQLITE_DONE ) rc = SQLITE_OK;
|
|
goto end_playback;
|
|
}
|
|
sqlite3OsSeek(pPager->jfd, 0);
|
|
pPager->journalOff = 0;
|
|
|
|
/* This loop terminates either when the readJournalHdr() call returns
|
|
** SQLITE_DONE or an IO error occurs. */
|
|
while( 1 ){
|
|
|
|
/* Read the next journal header from the journal file. If there are
|
|
** not enough bytes left in the journal file for a complete header, or
|
|
** it is corrupted, then a process must of failed while writing it.
|
|
** This indicates nothing more needs to be rolled back.
|
|
*/
|
|
rc = readJournalHdr(pPager, szJ, &nRec, &mxPg);
|
|
if( rc!=SQLITE_OK ){
|
|
if( rc==SQLITE_DONE ){
|
|
rc = SQLITE_OK;
|
|
}
|
|
goto end_playback;
|
|
}
|
|
|
|
/* If nRec is 0xffffffff, then this journal was created by a process
|
|
** working in no-sync mode. This means that the rest of the journal
|
|
** file consists of pages, there are no more journal headers. Compute
|
|
** the value of nRec based on this assumption.
|
|
*/
|
|
if( nRec==0xffffffff ){
|
|
assert( pPager->journalOff==JOURNAL_HDR_SZ(pPager) );
|
|
nRec = (szJ - JOURNAL_HDR_SZ(pPager))/JOURNAL_PG_SZ(pPager);
|
|
}
|
|
|
|
/* If nRec is 0 and this rollback is of a transaction created by this
|
|
** process. In this case the rest of the journal file consists of
|
|
** journalled copies of pages that need to be read back into the cache.
|
|
*/
|
|
if( nRec==0 && !isHot ){
|
|
nRec = (szJ - pPager->journalOff) / JOURNAL_PG_SZ(pPager);
|
|
}
|
|
|
|
/* If this is the first header read from the journal, truncate the
|
|
** database file back to it's original size.
|
|
*/
|
|
if( pPager->journalOff==JOURNAL_HDR_SZ(pPager) ){
|
|
rc = pager_truncate(pPager, mxPg);
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_playback;
|
|
}
|
|
}
|
|
|
|
/* Copy original pages out of the journal and back into the database file.
|
|
*/
|
|
for(i=0; i<nRec; i++){
|
|
rc = pager_playback_one_page(pPager, pPager->jfd, 1);
|
|
if( rc!=SQLITE_OK ){
|
|
if( rc==SQLITE_DONE ){
|
|
rc = SQLITE_OK;
|
|
pPager->journalOff = szJ;
|
|
break;
|
|
}else{
|
|
goto end_playback;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
/*NOTREACHED*/
|
|
assert( 0 );
|
|
|
|
end_playback:
|
|
if( rc==SQLITE_OK ){
|
|
rc = pager_end_transaction(pPager);
|
|
}
|
|
if( zMaster ){
|
|
/* If there was a master journal and this routine will return success,
|
|
** see if it is possible to delete the master journal.
|
|
*/
|
|
if( rc==SQLITE_OK ){
|
|
rc = pager_delmaster(zMaster);
|
|
}
|
|
sqliteFree(zMaster);
|
|
}
|
|
|
|
/* The Pager.sectorSize variable may have been updated while rolling
|
|
** back a journal created by a process with a different sector size
|
|
** value. Reset it to the correct value for this process.
|
|
*/
|
|
setSectorSize(pPager);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Playback the statement journal.
|
|
**
|
|
** This is similar to playing back the transaction journal but with
|
|
** a few extra twists.
|
|
**
|
|
** (1) The number of pages in the database file at the start of
|
|
** the statement is stored in pPager->stmtSize, not in the
|
|
** journal file itself.
|
|
**
|
|
** (2) In addition to playing back the statement journal, also
|
|
** playback all pages of the transaction journal beginning
|
|
** at offset pPager->stmtJSize.
|
|
*/
|
|
static int pager_stmt_playback(Pager *pPager){
|
|
i64 szJ; /* Size of the full journal */
|
|
i64 hdrOff;
|
|
int nRec; /* Number of Records */
|
|
int i; /* Loop counter */
|
|
int rc;
|
|
|
|
szJ = pPager->journalOff;
|
|
#ifndef NDEBUG
|
|
{
|
|
i64 os_szJ;
|
|
rc = sqlite3OsFileSize(pPager->jfd, &os_szJ);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
assert( szJ==os_szJ );
|
|
}
|
|
#endif
|
|
|
|
/* Set hdrOff to be the offset just after the end of the last journal
|
|
** page written before the first journal-header for this statement
|
|
** transaction was written, or the end of the file if no journal
|
|
** header was written.
|
|
*/
|
|
hdrOff = pPager->stmtHdrOff;
|
|
assert( pPager->fullSync || !hdrOff );
|
|
if( !hdrOff ){
|
|
hdrOff = szJ;
|
|
}
|
|
|
|
/* Truncate the database back to its original size.
|
|
*/
|
|
rc = pager_truncate(pPager, pPager->stmtSize);
|
|
assert( pPager->state>=PAGER_SHARED );
|
|
|
|
/* Figure out how many records are in the statement journal.
|
|
*/
|
|
assert( pPager->stmtInUse && pPager->journalOpen );
|
|
sqlite3OsSeek(pPager->stfd, 0);
|
|
nRec = pPager->stmtNRec;
|
|
|
|
/* Copy original pages out of the statement journal and back into the
|
|
** database file. Note that the statement journal omits checksums from
|
|
** each record since power-failure recovery is not important to statement
|
|
** journals.
|
|
*/
|
|
for(i=nRec-1; i>=0; i--){
|
|
rc = pager_playback_one_page(pPager, pPager->stfd, 0);
|
|
assert( rc!=SQLITE_DONE );
|
|
if( rc!=SQLITE_OK ) goto end_stmt_playback;
|
|
}
|
|
|
|
/* Now roll some pages back from the transaction journal. Pager.stmtJSize
|
|
** was the size of the journal file when this statement was started, so
|
|
** everything after that needs to be rolled back, either into the
|
|
** database, the memory cache, or both.
|
|
**
|
|
** If it is not zero, then Pager.stmtHdrOff is the offset to the start
|
|
** of the first journal header written during this statement transaction.
|
|
*/
|
|
rc = sqlite3OsSeek(pPager->jfd, pPager->stmtJSize);
|
|
if( rc!=SQLITE_OK ){
|
|
goto end_stmt_playback;
|
|
}
|
|
pPager->journalOff = pPager->stmtJSize;
|
|
pPager->cksumInit = pPager->stmtCksum;
|
|
while( pPager->journalOff < hdrOff ){
|
|
rc = pager_playback_one_page(pPager, pPager->jfd, 1);
|
|
assert( rc!=SQLITE_DONE );
|
|
if( rc!=SQLITE_OK ) goto end_stmt_playback;
|
|
}
|
|
|
|
while( pPager->journalOff < szJ ){
|
|
u32 nJRec; /* Number of Journal Records */
|
|
u32 dummy;
|
|
rc = readJournalHdr(pPager, szJ, &nJRec, &dummy);
|
|
if( rc!=SQLITE_OK ){
|
|
assert( rc!=SQLITE_DONE );
|
|
goto end_stmt_playback;
|
|
}
|
|
if( nJRec==0 ){
|
|
nJRec = (szJ - pPager->journalOff) / (pPager->pageSize+8);
|
|
}
|
|
for(i=nJRec-1; i>=0 && pPager->journalOff < szJ; i--){
|
|
rc = pager_playback_one_page(pPager, pPager->jfd, 1);
|
|
assert( rc!=SQLITE_DONE );
|
|
if( rc!=SQLITE_OK ) goto end_stmt_playback;
|
|
}
|
|
}
|
|
|
|
pPager->journalOff = szJ;
|
|
|
|
end_stmt_playback:
|
|
if( rc==SQLITE_OK) {
|
|
pPager->journalOff = szJ;
|
|
/* pager_reload_cache(pPager); */
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Change the maximum number of in-memory pages that are allowed.
|
|
*/
|
|
void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
|
|
if( mxPage>10 ){
|
|
pPager->mxPage = mxPage;
|
|
}else{
|
|
pPager->mxPage = 10;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Adjust the robustness of the database to damage due to OS crashes
|
|
** or power failures by changing the number of syncs()s when writing
|
|
** the rollback journal. There are three levels:
|
|
**
|
|
** OFF sqlite3OsSync() is never called. This is the default
|
|
** for temporary and transient files.
|
|
**
|
|
** NORMAL The journal is synced once before writes begin on the
|
|
** database. This is normally adequate protection, but
|
|
** it is theoretically possible, though very unlikely,
|
|
** that an inopertune power failure could leave the journal
|
|
** in a state which would cause damage to the database
|
|
** when it is rolled back.
|
|
**
|
|
** FULL The journal is synced twice before writes begin on the
|
|
** database (with some additional information - the nRec field
|
|
** of the journal header - being written in between the two
|
|
** syncs). If we assume that writing a
|
|
** single disk sector is atomic, then this mode provides
|
|
** assurance that the journal will not be corrupted to the
|
|
** point of causing damage to the database during rollback.
|
|
**
|
|
** Numeric values associated with these states are OFF==1, NORMAL=2,
|
|
** and FULL=3.
|
|
*/
|
|
#ifndef SQLITE_OMIT_PAGER_PRAGMAS
|
|
void sqlite3PagerSetSafetyLevel(Pager *pPager, int level, int full_fsync){
|
|
pPager->noSync = level==1 || pPager->tempFile;
|
|
pPager->fullSync = level==3 && !pPager->tempFile;
|
|
pPager->full_fsync = full_fsync;
|
|
if( pPager->noSync ) pPager->needSync = 0;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** The following global variable is incremented whenever the library
|
|
** attempts to open a temporary file. This information is used for
|
|
** testing and analysis only.
|
|
*/
|
|
#ifdef SQLITE_TEST
|
|
int sqlite3_opentemp_count = 0;
|
|
#endif
|
|
|
|
/*
|
|
** Open a temporary file.
|
|
**
|
|
** Write the file descriptor into *fd. Return SQLITE_OK on success or some
|
|
** other error code if we fail.
|
|
**
|
|
** The OS will automatically delete the temporary file when it is
|
|
** closed.
|
|
*/
|
|
static int sqlite3PagerOpentemp(OsFile **pFd){
|
|
int cnt = 8;
|
|
int rc;
|
|
char zFile[SQLITE_TEMPNAME_SIZE];
|
|
|
|
#ifdef SQLITE_TEST
|
|
sqlite3_opentemp_count++; /* Used for testing and analysis only */
|
|
#endif
|
|
do{
|
|
cnt--;
|
|
sqlite3OsTempFileName(zFile);
|
|
rc = sqlite3OsOpenExclusive(zFile, pFd, 1);
|
|
assert( rc!=SQLITE_OK || *pFd );
|
|
}while( cnt>0 && rc!=SQLITE_OK && rc!=SQLITE_NOMEM );
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Create a new page cache and put a pointer to the page cache in *ppPager.
|
|
** The file to be cached need not exist. The file is not locked until
|
|
** the first call to sqlite3PagerGet() and is only held open until the
|
|
** last page is released using sqlite3PagerUnref().
|
|
**
|
|
** If zFilename is NULL then a randomly-named temporary file is created
|
|
** and used as the file to be cached. The file will be deleted
|
|
** automatically when it is closed.
|
|
**
|
|
** If zFilename is ":memory:" then all information is held in cache.
|
|
** It is never written to disk. This can be used to implement an
|
|
** in-memory database.
|
|
*/
|
|
int sqlite3PagerOpen(
|
|
Pager **ppPager, /* Return the Pager structure here */
|
|
const char *zFilename, /* Name of the database file to open */
|
|
int nExtra, /* Extra bytes append to each in-memory page */
|
|
int flags /* flags controlling this file */
|
|
){
|
|
Pager *pPager = 0;
|
|
char *zFullPathname = 0;
|
|
int nameLen; /* Compiler is wrong. This is always initialized before use */
|
|
OsFile *fd = 0;
|
|
int rc = SQLITE_OK;
|
|
int i;
|
|
int tempFile = 0;
|
|
int memDb = 0;
|
|
int readOnly = 0;
|
|
int useJournal = (flags & PAGER_OMIT_JOURNAL)==0;
|
|
int noReadlock = (flags & PAGER_NO_READLOCK)!=0;
|
|
char zTemp[SQLITE_TEMPNAME_SIZE];
|
|
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
|
|
/* A malloc() cannot fail in sqlite3ThreadData() as one or more calls to
|
|
** malloc() must have already been made by this thread before it gets
|
|
** to this point. This means the ThreadData must have been allocated already
|
|
** so that ThreadData.nAlloc can be set. It would be nice to assert
|
|
** that ThreadData.nAlloc is non-zero, but alas this breaks test cases
|
|
** written to invoke the pager directly.
|
|
*/
|
|
ThreadData *pTsd = sqlite3ThreadData();
|
|
assert( pTsd );
|
|
#endif
|
|
|
|
/* We used to test if malloc() had already failed before proceeding.
|
|
** But the way this function is used in SQLite means that can never
|
|
** happen. Furthermore, if the malloc-failed flag is already set,
|
|
** either the call to sqliteStrDup() or sqliteMalloc() below will
|
|
** fail shortly and SQLITE_NOMEM returned anyway.
|
|
*/
|
|
*ppPager = 0;
|
|
|
|
/* Open the pager file and set zFullPathname to point at malloc()ed
|
|
** memory containing the complete filename (i.e. including the directory).
|
|
*/
|
|
if( zFilename && zFilename[0] ){
|
|
#ifndef SQLITE_OMIT_MEMORYDB
|
|
if( strcmp(zFilename,":memory:")==0 ){
|
|
memDb = 1;
|
|
zFullPathname = sqliteStrDup("");
|
|
}else
|
|
#endif
|
|
{
|
|
zFullPathname = sqlite3OsFullPathname(zFilename);
|
|
if( zFullPathname ){
|
|
rc = sqlite3OsOpenReadWrite(zFullPathname, &fd, &readOnly);
|
|
assert( rc!=SQLITE_OK || fd );
|
|
}
|
|
}
|
|
}else{
|
|
rc = sqlite3PagerOpentemp(&fd);
|
|
sqlite3OsTempFileName(zTemp);
|
|
zFilename = zTemp;
|
|
zFullPathname = sqlite3OsFullPathname(zFilename);
|
|
if( rc==SQLITE_OK ){
|
|
tempFile = 1;
|
|
}
|
|
}
|
|
|
|
/* Allocate the Pager structure. As part of the same allocation, allocate
|
|
** space for the full paths of the file, directory and journal
|
|
** (Pager.zFilename, Pager.zDirectory and Pager.zJournal).
|
|
*/
|
|
if( zFullPathname ){
|
|
nameLen = strlen(zFullPathname);
|
|
pPager = sqliteMalloc( sizeof(*pPager) + nameLen*3 + 30 );
|
|
if( pPager && rc==SQLITE_OK ){
|
|
pPager->pTmpSpace = (char *)sqliteMallocRaw(SQLITE_DEFAULT_PAGE_SIZE);
|
|
}
|
|
}
|
|
|
|
|
|
/* If an error occured in either of the blocks above, free the memory
|
|
** pointed to by zFullPathname, free the Pager structure and close the
|
|
** file. Since the pager is not allocated there is no need to set
|
|
** any Pager.errMask variables.
|
|
*/
|
|
if( !pPager || !zFullPathname || !pPager->pTmpSpace || rc!=SQLITE_OK ){
|
|
sqlite3OsClose(&fd);
|
|
sqliteFree(zFullPathname);
|
|
sqliteFree(pPager);
|
|
return ((rc==SQLITE_OK)?SQLITE_NOMEM:rc);
|
|
}
|
|
|
|
PAGERTRACE3("OPEN %d %s\n", FILEHANDLEID(fd), zFullPathname);
|
|
IOTRACE(("OPEN %p %s\n", pPager, zFullPathname))
|
|
pPager->zFilename = (char*)&pPager[1];
|
|
pPager->zDirectory = &pPager->zFilename[nameLen+1];
|
|
pPager->zJournal = &pPager->zDirectory[nameLen+1];
|
|
memcpy(pPager->zFilename, zFullPathname, nameLen+1);
|
|
memcpy(pPager->zDirectory, zFullPathname, nameLen+1);
|
|
|
|
for(i=nameLen; i>0 && pPager->zDirectory[i-1]!='/'; i--){}
|
|
if( i>0 ) pPager->zDirectory[i-1] = 0;
|
|
memcpy(pPager->zJournal, zFullPathname,nameLen);
|
|
sqliteFree(zFullPathname);
|
|
memcpy(&pPager->zJournal[nameLen], "-journal",sizeof("-journal"));
|
|
pPager->fd = fd;
|
|
/* pPager->journalOpen = 0; */
|
|
pPager->useJournal = useJournal && !memDb;
|
|
pPager->noReadlock = noReadlock && readOnly;
|
|
/* pPager->stmtOpen = 0; */
|
|
/* pPager->stmtInUse = 0; */
|
|
/* pPager->nRef = 0; */
|
|
pPager->dbSize = memDb-1;
|
|
pPager->pageSize = SQLITE_DEFAULT_PAGE_SIZE;
|
|
/* pPager->stmtSize = 0; */
|
|
/* pPager->stmtJSize = 0; */
|
|
/* pPager->nPage = 0; */
|
|
pPager->mxPage = 100;
|
|
pPager->mxPgno = SQLITE_MAX_PAGE_COUNT;
|
|
assert( PAGER_UNLOCK==0 );
|
|
/* pPager->state = PAGER_UNLOCK; */
|
|
/* pPager->errMask = 0; */
|
|
pPager->tempFile = tempFile;
|
|
assert( tempFile==PAGER_LOCKINGMODE_NORMAL
|
|
|| tempFile==PAGER_LOCKINGMODE_EXCLUSIVE );
|
|
assert( PAGER_LOCKINGMODE_EXCLUSIVE==1 );
|
|
pPager->exclusiveMode = tempFile;
|
|
pPager->memDb = memDb;
|
|
pPager->readOnly = readOnly;
|
|
/* pPager->needSync = 0; */
|
|
pPager->noSync = pPager->tempFile || !useJournal;
|
|
pPager->fullSync = (pPager->noSync?0:1);
|
|
/* pPager->pFirst = 0; */
|
|
/* pPager->pFirstSynced = 0; */
|
|
/* pPager->pLast = 0; */
|
|
pPager->nExtra = FORCE_ALIGNMENT(nExtra);
|
|
assert(fd||memDb);
|
|
if( !memDb ){
|
|
setSectorSize(pPager);
|
|
}
|
|
/* pPager->pBusyHandler = 0; */
|
|
/* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
|
|
*ppPager = pPager;
|
|
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
|
|
pPager->pNext = pTsd->pPager;
|
|
pTsd->pPager = pPager;
|
|
#endif
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Set the busy handler function.
|
|
*/
|
|
void sqlite3PagerSetBusyhandler(Pager *pPager, BusyHandler *pBusyHandler){
|
|
pPager->pBusyHandler = pBusyHandler;
|
|
}
|
|
|
|
/*
|
|
** Set the destructor for this pager. If not NULL, the destructor is called
|
|
** when the reference count on each page reaches zero. The destructor can
|
|
** be used to clean up information in the extra segment appended to each page.
|
|
**
|
|
** The destructor is not called as a result sqlite3PagerClose().
|
|
** Destructors are only called by sqlite3PagerUnref().
|
|
*/
|
|
void sqlite3PagerSetDestructor(Pager *pPager, void (*xDesc)(DbPage*,int)){
|
|
pPager->xDestructor = xDesc;
|
|
}
|
|
|
|
/*
|
|
** Set the reinitializer for this pager. If not NULL, the reinitializer
|
|
** is called when the content of a page in cache is restored to its original
|
|
** value as a result of a rollback. The callback gives higher-level code
|
|
** an opportunity to restore the EXTRA section to agree with the restored
|
|
** page data.
|
|
*/
|
|
void sqlite3PagerSetReiniter(Pager *pPager, void (*xReinit)(DbPage*,int)){
|
|
pPager->xReiniter = xReinit;
|
|
}
|
|
|
|
/*
|
|
** Set the page size. Return the new size. If the suggest new page
|
|
** size is inappropriate, then an alternative page size is selected
|
|
** and returned.
|
|
*/
|
|
int sqlite3PagerSetPagesize(Pager *pPager, int pageSize){
|
|
assert( pageSize>=512 && pageSize<=SQLITE_MAX_PAGE_SIZE );
|
|
if( !pPager->memDb && pPager->nRef==0 ){
|
|
pager_reset(pPager);
|
|
pPager->pageSize = pageSize;
|
|
pPager->pTmpSpace = sqlite3ReallocOrFree(pPager->pTmpSpace, pageSize);
|
|
}
|
|
return pPager->pageSize;
|
|
}
|
|
|
|
/*
|
|
** Attempt to set the maximum database page count if mxPage is positive.
|
|
** Make no changes if mxPage is zero or negative. And never reduce the
|
|
** maximum page count below the current size of the database.
|
|
**
|
|
** Regardless of mxPage, return the current maximum page count.
|
|
*/
|
|
int sqlite3PagerMaxPageCount(Pager *pPager, int mxPage){
|
|
if( mxPage>0 ){
|
|
pPager->mxPgno = mxPage;
|
|
}
|
|
sqlite3PagerPagecount(pPager);
|
|
return pPager->mxPgno;
|
|
}
|
|
|
|
/*
|
|
** The following set of routines are used to disable the simulated
|
|
** I/O error mechanism. These routines are used to avoid simulated
|
|
** errors in places where we do not care about errors.
|
|
**
|
|
** Unless -DSQLITE_TEST=1 is used, these routines are all no-ops
|
|
** and generate no code.
|
|
*/
|
|
#ifdef SQLITE_TEST
|
|
extern int sqlite3_io_error_pending;
|
|
extern int sqlite3_io_error_hit;
|
|
static int saved_cnt;
|
|
void disable_simulated_io_errors(void){
|
|
saved_cnt = sqlite3_io_error_pending;
|
|
sqlite3_io_error_pending = -1;
|
|
}
|
|
void enable_simulated_io_errors(void){
|
|
sqlite3_io_error_pending = saved_cnt;
|
|
}
|
|
#else
|
|
# define disable_simulated_io_errors()
|
|
# define enable_simulated_io_errors()
|
|
#endif
|
|
|
|
/*
|
|
** Read the first N bytes from the beginning of the file into memory
|
|
** that pDest points to.
|
|
**
|
|
** No error checking is done. The rational for this is that this function
|
|
** may be called even if the file does not exist or contain a header. In
|
|
** these cases sqlite3OsRead() will return an error, to which the correct
|
|
** response is to zero the memory at pDest and continue. A real IO error
|
|
** will presumably recur and be picked up later (Todo: Think about this).
|
|
*/
|
|
int sqlite3PagerReadFileheader(Pager *pPager, int N, unsigned char *pDest){
|
|
int rc = SQLITE_OK;
|
|
memset(pDest, 0, N);
|
|
if( MEMDB==0 ){
|
|
disable_simulated_io_errors();
|
|
sqlite3OsSeek(pPager->fd, 0);
|
|
enable_simulated_io_errors();
|
|
IOTRACE(("DBHDR %p 0 %d\n", pPager, N))
|
|
rc = sqlite3OsRead(pPager->fd, pDest, N);
|
|
if( rc==SQLITE_IOERR_SHORT_READ ){
|
|
rc = SQLITE_OK;
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the total number of pages in the disk file associated with
|
|
** pPager.
|
|
**
|
|
** If the PENDING_BYTE lies on the page directly after the end of the
|
|
** file, then consider this page part of the file too. For example, if
|
|
** PENDING_BYTE is byte 4096 (the first byte of page 5) and the size of the
|
|
** file is 4096 bytes, 5 is returned instead of 4.
|
|
*/
|
|
int sqlite3PagerPagecount(Pager *pPager){
|
|
i64 n;
|
|
int rc;
|
|
assert( pPager!=0 );
|
|
if( pPager->errCode ){
|
|
return 0;
|
|
}
|
|
if( pPager->dbSize>=0 ){
|
|
n = pPager->dbSize;
|
|
} else {
|
|
if( (rc = sqlite3OsFileSize(pPager->fd, &n))!=SQLITE_OK ){
|
|
pager_error(pPager, rc);
|
|
return 0;
|
|
}
|
|
if( n>0 && n<pPager->pageSize ){
|
|
n = 1;
|
|
}else{
|
|
n /= pPager->pageSize;
|
|
}
|
|
if( pPager->state!=PAGER_UNLOCK ){
|
|
pPager->dbSize = n;
|
|
}
|
|
}
|
|
if( n==(PENDING_BYTE/pPager->pageSize) ){
|
|
n++;
|
|
}
|
|
if( n>pPager->mxPgno ){
|
|
pPager->mxPgno = n;
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
#ifndef SQLITE_OMIT_MEMORYDB
|
|
/*
|
|
** Clear a PgHistory block
|
|
*/
|
|
static void clearHistory(PgHistory *pHist){
|
|
sqliteFree(pHist->pOrig);
|
|
sqliteFree(pHist->pStmt);
|
|
pHist->pOrig = 0;
|
|
pHist->pStmt = 0;
|
|
}
|
|
#else
|
|
#define clearHistory(x)
|
|
#endif
|
|
|
|
/*
|
|
** Forward declaration
|
|
*/
|
|
static int syncJournal(Pager*);
|
|
|
|
/*
|
|
** Unlink pPg from it's hash chain. Also set the page number to 0 to indicate
|
|
** that the page is not part of any hash chain. This is required because the
|
|
** sqlite3PagerMovepage() routine can leave a page in the
|
|
** pNextFree/pPrevFree list that is not a part of any hash-chain.
|
|
*/
|
|
static void unlinkHashChain(Pager *pPager, PgHdr *pPg){
|
|
if( pPg->pgno==0 ){
|
|
assert( pPg->pNextHash==0 && pPg->pPrevHash==0 );
|
|
return;
|
|
}
|
|
if( pPg->pNextHash ){
|
|
pPg->pNextHash->pPrevHash = pPg->pPrevHash;
|
|
}
|
|
if( pPg->pPrevHash ){
|
|
assert( pPager->aHash[pPg->pgno & (pPager->nHash-1)]!=pPg );
|
|
pPg->pPrevHash->pNextHash = pPg->pNextHash;
|
|
}else{
|
|
int h = pPg->pgno & (pPager->nHash-1);
|
|
pPager->aHash[h] = pPg->pNextHash;
|
|
}
|
|
if( MEMDB ){
|
|
clearHistory(PGHDR_TO_HIST(pPg, pPager));
|
|
}
|
|
pPg->pgno = 0;
|
|
pPg->pNextHash = pPg->pPrevHash = 0;
|
|
}
|
|
|
|
/*
|
|
** Unlink a page from the free list (the list of all pages where nRef==0)
|
|
** and from its hash collision chain.
|
|
*/
|
|
static void unlinkPage(PgHdr *pPg){
|
|
Pager *pPager = pPg->pPager;
|
|
|
|
/* Keep the pFirstSynced pointer pointing at the first synchronized page */
|
|
if( pPg==pPager->pFirstSynced ){
|
|
PgHdr *p = pPg->pNextFree;
|
|
while( p && p->needSync ){ p = p->pNextFree; }
|
|
pPager->pFirstSynced = p;
|
|
}
|
|
|
|
/* Unlink from the freelist */
|
|
if( pPg->pPrevFree ){
|
|
pPg->pPrevFree->pNextFree = pPg->pNextFree;
|
|
}else{
|
|
assert( pPager->pFirst==pPg );
|
|
pPager->pFirst = pPg->pNextFree;
|
|
}
|
|
if( pPg->pNextFree ){
|
|
pPg->pNextFree->pPrevFree = pPg->pPrevFree;
|
|
}else{
|
|
assert( pPager->pLast==pPg );
|
|
pPager->pLast = pPg->pPrevFree;
|
|
}
|
|
pPg->pNextFree = pPg->pPrevFree = 0;
|
|
|
|
/* Unlink from the pgno hash table */
|
|
unlinkHashChain(pPager, pPg);
|
|
}
|
|
|
|
/*
|
|
** This routine is used to truncate the cache when a database
|
|
** is truncated. Drop from the cache all pages whose pgno is
|
|
** larger than pPager->dbSize and is unreferenced.
|
|
**
|
|
** Referenced pages larger than pPager->dbSize are zeroed.
|
|
**
|
|
** Actually, at the point this routine is called, it would be
|
|
** an error to have a referenced page. But rather than delete
|
|
** that page and guarantee a subsequent segfault, it seems better
|
|
** to zero it and hope that we error out sanely.
|
|
*/
|
|
static void pager_truncate_cache(Pager *pPager){
|
|
PgHdr *pPg;
|
|
PgHdr **ppPg;
|
|
int dbSize = pPager->dbSize;
|
|
|
|
ppPg = &pPager->pAll;
|
|
while( (pPg = *ppPg)!=0 ){
|
|
if( pPg->pgno<=dbSize ){
|
|
ppPg = &pPg->pNextAll;
|
|
}else if( pPg->nRef>0 ){
|
|
memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
|
|
ppPg = &pPg->pNextAll;
|
|
}else{
|
|
*ppPg = pPg->pNextAll;
|
|
IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
|
|
PAGER_INCR(sqlite3_pager_pgfree_count);
|
|
unlinkPage(pPg);
|
|
makeClean(pPg);
|
|
sqliteFree(pPg);
|
|
pPager->nPage--;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Try to obtain a lock on a file. Invoke the busy callback if the lock
|
|
** is currently not available. Repeat until the busy callback returns
|
|
** false or until the lock succeeds.
|
|
**
|
|
** Return SQLITE_OK on success and an error code if we cannot obtain
|
|
** the lock.
|
|
*/
|
|
static int pager_wait_on_lock(Pager *pPager, int locktype){
|
|
int rc;
|
|
|
|
/* The OS lock values must be the same as the Pager lock values */
|
|
assert( PAGER_SHARED==SHARED_LOCK );
|
|
assert( PAGER_RESERVED==RESERVED_LOCK );
|
|
assert( PAGER_EXCLUSIVE==EXCLUSIVE_LOCK );
|
|
|
|
/* If the file is currently unlocked then the size must be unknown */
|
|
assert( pPager->state>=PAGER_SHARED || pPager->dbSize<0 || MEMDB );
|
|
|
|
if( pPager->state>=locktype ){
|
|
rc = SQLITE_OK;
|
|
}else{
|
|
do {
|
|
rc = sqlite3OsLock(pPager->fd, locktype);
|
|
}while( rc==SQLITE_BUSY && sqlite3InvokeBusyHandler(pPager->pBusyHandler) );
|
|
if( rc==SQLITE_OK ){
|
|
pPager->state = locktype;
|
|
IOTRACE(("LOCK %p %d\n", pPager, locktype))
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Truncate the file to the number of pages specified.
|
|
*/
|
|
int sqlite3PagerTruncate(Pager *pPager, Pgno nPage){
|
|
int rc;
|
|
assert( pPager->state>=PAGER_SHARED || MEMDB );
|
|
sqlite3PagerPagecount(pPager);
|
|
if( pPager->errCode ){
|
|
rc = pPager->errCode;
|
|
return rc;
|
|
}
|
|
if( nPage>=(unsigned)pPager->dbSize ){
|
|
return SQLITE_OK;
|
|
}
|
|
if( MEMDB ){
|
|
pPager->dbSize = nPage;
|
|
pager_truncate_cache(pPager);
|
|
return SQLITE_OK;
|
|
}
|
|
rc = syncJournal(pPager);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
/* Get an exclusive lock on the database before truncating. */
|
|
rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
rc = pager_truncate(pPager, nPage);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Shutdown the page cache. Free all memory and close all files.
|
|
**
|
|
** If a transaction was in progress when this routine is called, that
|
|
** transaction is rolled back. All outstanding pages are invalidated
|
|
** and their memory is freed. Any attempt to use a page associated
|
|
** with this page cache after this function returns will likely
|
|
** result in a coredump.
|
|
**
|
|
** This function always succeeds. If a transaction is active an attempt
|
|
** is made to roll it back. If an error occurs during the rollback
|
|
** a hot journal may be left in the filesystem but no error is returned
|
|
** to the caller.
|
|
*/
|
|
int sqlite3PagerClose(Pager *pPager){
|
|
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
|
|
/* A malloc() cannot fail in sqlite3ThreadData() as one or more calls to
|
|
** malloc() must have already been made by this thread before it gets
|
|
** to this point. This means the ThreadData must have been allocated already
|
|
** so that ThreadData.nAlloc can be set.
|
|
*/
|
|
ThreadData *pTsd = sqlite3ThreadData();
|
|
assert( pPager );
|
|
assert( pTsd && pTsd->nAlloc );
|
|
#endif
|
|
|
|
disable_simulated_io_errors();
|
|
pPager->errCode = 0;
|
|
pPager->exclusiveMode = 0;
|
|
pager_reset(pPager);
|
|
pagerUnlockAndRollback(pPager);
|
|
enable_simulated_io_errors();
|
|
PAGERTRACE2("CLOSE %d\n", PAGERID(pPager));
|
|
IOTRACE(("CLOSE %p\n", pPager))
|
|
assert( pPager->errCode || (pPager->journalOpen==0 && pPager->stmtOpen==0) );
|
|
if( pPager->journalOpen ){
|
|
sqlite3OsClose(&pPager->jfd);
|
|
}
|
|
sqliteFree(pPager->aInJournal);
|
|
if( pPager->stmtOpen ){
|
|
sqlite3OsClose(&pPager->stfd);
|
|
}
|
|
sqlite3OsClose(&pPager->fd);
|
|
/* Temp files are automatically deleted by the OS
|
|
** if( pPager->tempFile ){
|
|
** sqlite3OsDelete(pPager->zFilename);
|
|
** }
|
|
*/
|
|
|
|
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
|
|
/* Remove the pager from the linked list of pagers starting at
|
|
** ThreadData.pPager if memory-management is enabled.
|
|
*/
|
|
if( pPager==pTsd->pPager ){
|
|
pTsd->pPager = pPager->pNext;
|
|
}else{
|
|
Pager *pTmp;
|
|
for(pTmp = pTsd->pPager; pTmp->pNext!=pPager; pTmp=pTmp->pNext){}
|
|
pTmp->pNext = pPager->pNext;
|
|
}
|
|
#endif
|
|
sqliteFree(pPager->aHash);
|
|
sqliteFree(pPager->pTmpSpace);
|
|
sqliteFree(pPager);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
#if !defined(NDEBUG) || defined(SQLITE_TEST)
|
|
/*
|
|
** Return the page number for the given page data.
|
|
*/
|
|
Pgno sqlite3PagerPagenumber(DbPage *p){
|
|
return p->pgno;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** The page_ref() function increments the reference count for a page.
|
|
** If the page is currently on the freelist (the reference count is zero) then
|
|
** remove it from the freelist.
|
|
**
|
|
** For non-test systems, page_ref() is a macro that calls _page_ref()
|
|
** online of the reference count is zero. For test systems, page_ref()
|
|
** is a real function so that we can set breakpoints and trace it.
|
|
*/
|
|
static void _page_ref(PgHdr *pPg){
|
|
if( pPg->nRef==0 ){
|
|
/* The page is currently on the freelist. Remove it. */
|
|
if( pPg==pPg->pPager->pFirstSynced ){
|
|
PgHdr *p = pPg->pNextFree;
|
|
while( p && p->needSync ){ p = p->pNextFree; }
|
|
pPg->pPager->pFirstSynced = p;
|
|
}
|
|
if( pPg->pPrevFree ){
|
|
pPg->pPrevFree->pNextFree = pPg->pNextFree;
|
|
}else{
|
|
pPg->pPager->pFirst = pPg->pNextFree;
|
|
}
|
|
if( pPg->pNextFree ){
|
|
pPg->pNextFree->pPrevFree = pPg->pPrevFree;
|
|
}else{
|
|
pPg->pPager->pLast = pPg->pPrevFree;
|
|
}
|
|
pPg->pPager->nRef++;
|
|
}
|
|
pPg->nRef++;
|
|
REFINFO(pPg);
|
|
}
|
|
#ifdef SQLITE_DEBUG
|
|
static void page_ref(PgHdr *pPg){
|
|
if( pPg->nRef==0 ){
|
|
_page_ref(pPg);
|
|
}else{
|
|
pPg->nRef++;
|
|
REFINFO(pPg);
|
|
}
|
|
}
|
|
#else
|
|
# define page_ref(P) ((P)->nRef==0?_page_ref(P):(void)(P)->nRef++)
|
|
#endif
|
|
|
|
/*
|
|
** Increment the reference count for a page. The input pointer is
|
|
** a reference to the page data.
|
|
*/
|
|
int sqlite3PagerRef(DbPage *pPg){
|
|
page_ref(pPg);
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Sync the journal. In other words, make sure all the pages that have
|
|
** been written to the journal have actually reached the surface of the
|
|
** disk. It is not safe to modify the original database file until after
|
|
** the journal has been synced. If the original database is modified before
|
|
** the journal is synced and a power failure occurs, the unsynced journal
|
|
** data would be lost and we would be unable to completely rollback the
|
|
** database changes. Database corruption would occur.
|
|
**
|
|
** This routine also updates the nRec field in the header of the journal.
|
|
** (See comments on the pager_playback() routine for additional information.)
|
|
** If the sync mode is FULL, two syncs will occur. First the whole journal
|
|
** is synced, then the nRec field is updated, then a second sync occurs.
|
|
**
|
|
** For temporary databases, we do not care if we are able to rollback
|
|
** after a power failure, so sync occurs.
|
|
**
|
|
** This routine clears the needSync field of every page current held in
|
|
** memory.
|
|
*/
|
|
static int syncJournal(Pager *pPager){
|
|
PgHdr *pPg;
|
|
int rc = SQLITE_OK;
|
|
|
|
/* Sync the journal before modifying the main database
|
|
** (assuming there is a journal and it needs to be synced.)
|
|
*/
|
|
if( pPager->needSync ){
|
|
if( !pPager->tempFile ){
|
|
assert( pPager->journalOpen );
|
|
/* assert( !pPager->noSync ); // noSync might be set if synchronous
|
|
** was turned off after the transaction was started. Ticket #615 */
|
|
#ifndef NDEBUG
|
|
{
|
|
/* Make sure the pPager->nRec counter we are keeping agrees
|
|
** with the nRec computed from the size of the journal file.
|
|
*/
|
|
i64 jSz;
|
|
rc = sqlite3OsFileSize(pPager->jfd, &jSz);
|
|
if( rc!=0 ) return rc;
|
|
assert( pPager->journalOff==jSz );
|
|
}
|
|
#endif
|
|
{
|
|
/* Write the nRec value into the journal file header. If in
|
|
** full-synchronous mode, sync the journal first. This ensures that
|
|
** all data has really hit the disk before nRec is updated to mark
|
|
** it as a candidate for rollback.
|
|
*/
|
|
if( pPager->fullSync ){
|
|
PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
|
|
IOTRACE(("JSYNC %p\n", pPager))
|
|
rc = sqlite3OsSync(pPager->jfd, 0);
|
|
if( rc!=0 ) return rc;
|
|
}
|
|
rc = sqlite3OsSeek(pPager->jfd,
|
|
pPager->journalHdr + sizeof(aJournalMagic));
|
|
if( rc ) return rc;
|
|
IOTRACE(("JHDR %p %lld %d\n", pPager,
|
|
pPager->journalHdr + sizeof(aJournalMagic), 4))
|
|
rc = write32bits(pPager->jfd, pPager->nRec);
|
|
if( rc ) return rc;
|
|
|
|
rc = sqlite3OsSeek(pPager->jfd, pPager->journalOff);
|
|
if( rc ) return rc;
|
|
}
|
|
PAGERTRACE2("SYNC journal of %d\n", PAGERID(pPager));
|
|
IOTRACE(("JSYNC %p\n", pPager))
|
|
rc = sqlite3OsSync(pPager->jfd, pPager->full_fsync);
|
|
if( rc!=0 ) return rc;
|
|
pPager->journalStarted = 1;
|
|
}
|
|
pPager->needSync = 0;
|
|
|
|
/* Erase the needSync flag from every page.
|
|
*/
|
|
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
|
|
pPg->needSync = 0;
|
|
}
|
|
pPager->pFirstSynced = pPager->pFirst;
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
/* If the Pager.needSync flag is clear then the PgHdr.needSync
|
|
** flag must also be clear for all pages. Verify that this
|
|
** invariant is true.
|
|
*/
|
|
else{
|
|
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
|
|
assert( pPg->needSync==0 );
|
|
}
|
|
assert( pPager->pFirstSynced==pPager->pFirst );
|
|
}
|
|
#endif
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Merge two lists of pages connected by pDirty and in pgno order.
|
|
** Do not both fixing the pPrevDirty pointers.
|
|
*/
|
|
static PgHdr *merge_pagelist(PgHdr *pA, PgHdr *pB){
|
|
PgHdr result, *pTail;
|
|
pTail = &result;
|
|
while( pA && pB ){
|
|
if( pA->pgno<pB->pgno ){
|
|
pTail->pDirty = pA;
|
|
pTail = pA;
|
|
pA = pA->pDirty;
|
|
}else{
|
|
pTail->pDirty = pB;
|
|
pTail = pB;
|
|
pB = pB->pDirty;
|
|
}
|
|
}
|
|
if( pA ){
|
|
pTail->pDirty = pA;
|
|
}else if( pB ){
|
|
pTail->pDirty = pB;
|
|
}else{
|
|
pTail->pDirty = 0;
|
|
}
|
|
return result.pDirty;
|
|
}
|
|
|
|
/*
|
|
** Sort the list of pages in accending order by pgno. Pages are
|
|
** connected by pDirty pointers. The pPrevDirty pointers are
|
|
** corrupted by this sort.
|
|
*/
|
|
#define N_SORT_BUCKET_ALLOC 25
|
|
#define N_SORT_BUCKET 25
|
|
#ifdef SQLITE_TEST
|
|
int sqlite3_pager_n_sort_bucket = 0;
|
|
#undef N_SORT_BUCKET
|
|
#define N_SORT_BUCKET \
|
|
(sqlite3_pager_n_sort_bucket?sqlite3_pager_n_sort_bucket:N_SORT_BUCKET_ALLOC)
|
|
#endif
|
|
static PgHdr *sort_pagelist(PgHdr *pIn){
|
|
PgHdr *a[N_SORT_BUCKET_ALLOC], *p;
|
|
int i;
|
|
memset(a, 0, sizeof(a));
|
|
while( pIn ){
|
|
p = pIn;
|
|
pIn = p->pDirty;
|
|
p->pDirty = 0;
|
|
for(i=0; i<N_SORT_BUCKET-1; i++){
|
|
if( a[i]==0 ){
|
|
a[i] = p;
|
|
break;
|
|
}else{
|
|
p = merge_pagelist(a[i], p);
|
|
a[i] = 0;
|
|
}
|
|
}
|
|
if( i==N_SORT_BUCKET-1 ){
|
|
/* Coverage: To get here, there need to be 2^(N_SORT_BUCKET)
|
|
** elements in the input list. This is possible, but impractical.
|
|
** Testing this line is the point of global variable
|
|
** sqlite3_pager_n_sort_bucket.
|
|
*/
|
|
a[i] = merge_pagelist(a[i], p);
|
|
}
|
|
}
|
|
p = a[0];
|
|
for(i=1; i<N_SORT_BUCKET; i++){
|
|
p = merge_pagelist(p, a[i]);
|
|
}
|
|
return p;
|
|
}
|
|
|
|
/*
|
|
** Given a list of pages (connected by the PgHdr.pDirty pointer) write
|
|
** every one of those pages out to the database file and mark them all
|
|
** as clean.
|
|
*/
|
|
static int pager_write_pagelist(PgHdr *pList){
|
|
Pager *pPager;
|
|
int rc;
|
|
|
|
if( pList==0 ) return SQLITE_OK;
|
|
pPager = pList->pPager;
|
|
|
|
/* At this point there may be either a RESERVED or EXCLUSIVE lock on the
|
|
** database file. If there is already an EXCLUSIVE lock, the following
|
|
** calls to sqlite3OsLock() are no-ops.
|
|
**
|
|
** Moving the lock from RESERVED to EXCLUSIVE actually involves going
|
|
** through an intermediate state PENDING. A PENDING lock prevents new
|
|
** readers from attaching to the database but is unsufficient for us to
|
|
** write. The idea of a PENDING lock is to prevent new readers from
|
|
** coming in while we wait for existing readers to clear.
|
|
**
|
|
** While the pager is in the RESERVED state, the original database file
|
|
** is unchanged and we can rollback without having to playback the
|
|
** journal into the original database file. Once we transition to
|
|
** EXCLUSIVE, it means the database file has been changed and any rollback
|
|
** will require a journal playback.
|
|
*/
|
|
rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
pList = sort_pagelist(pList);
|
|
while( pList ){
|
|
assert( pList->dirty );
|
|
rc = sqlite3OsSeek(pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize);
|
|
if( rc ) return rc;
|
|
/* If there are dirty pages in the page cache with page numbers greater
|
|
** than Pager.dbSize, this means sqlite3PagerTruncate() was called to
|
|
** make the file smaller (presumably by auto-vacuum code). Do not write
|
|
** any such pages to the file.
|
|
*/
|
|
if( pList->pgno<=pPager->dbSize ){
|
|
char *pData = CODEC2(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
|
|
PAGERTRACE4("STORE %d page %d hash(%08x)\n",
|
|
PAGERID(pPager), pList->pgno, pager_pagehash(pList));
|
|
IOTRACE(("PGOUT %p %d\n", pPager, pList->pgno));
|
|
rc = sqlite3OsWrite(pPager->fd, pData, pPager->pageSize);
|
|
PAGER_INCR(sqlite3_pager_writedb_count);
|
|
PAGER_INCR(pPager->nWrite);
|
|
if( pList->pgno==1 ){
|
|
memcpy(&pPager->dbFileVers, &pData[24], sizeof(pPager->dbFileVers));
|
|
}
|
|
}
|
|
#ifndef NDEBUG
|
|
else{
|
|
PAGERTRACE3("NOSTORE %d page %d\n", PAGERID(pPager), pList->pgno);
|
|
}
|
|
#endif
|
|
if( rc ) return rc;
|
|
pList->dirty = 0;
|
|
#ifdef SQLITE_CHECK_PAGES
|
|
pList->pageHash = pager_pagehash(pList);
|
|
#endif
|
|
pList = pList->pDirty;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Collect every dirty page into a dirty list and
|
|
** return a pointer to the head of that list. All pages are
|
|
** collected even if they are still in use.
|
|
*/
|
|
static PgHdr *pager_get_all_dirty_pages(Pager *pPager){
|
|
return pPager->pDirty;
|
|
}
|
|
|
|
/*
|
|
** Return TRUE if there is a hot journal on the given pager.
|
|
** A hot journal is one that needs to be played back.
|
|
**
|
|
** If the current size of the database file is 0 but a journal file
|
|
** exists, that is probably an old journal left over from a prior
|
|
** database with the same name. Just delete the journal.
|
|
*/
|
|
static int hasHotJournal(Pager *pPager){
|
|
if( !pPager->useJournal ) return 0;
|
|
if( !sqlite3OsFileExists(pPager->zJournal) ){
|
|
return 0;
|
|
}
|
|
if( sqlite3OsCheckReservedLock(pPager->fd) ){
|
|
return 0;
|
|
}
|
|
if( sqlite3PagerPagecount(pPager)==0 ){
|
|
sqlite3OsDelete(pPager->zJournal);
|
|
return 0;
|
|
}else{
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Try to find a page in the cache that can be recycled.
|
|
**
|
|
** This routine may return SQLITE_IOERR, SQLITE_FULL or SQLITE_OK. It
|
|
** does not set the pPager->errCode variable.
|
|
*/
|
|
static int pager_recycle(Pager *pPager, int syncOk, PgHdr **ppPg){
|
|
PgHdr *pPg;
|
|
*ppPg = 0;
|
|
|
|
assert(!MEMDB);
|
|
|
|
/* Find a page to recycle. Try to locate a page that does not
|
|
** require us to do an fsync() on the journal.
|
|
*/
|
|
pPg = pPager->pFirstSynced;
|
|
|
|
/* If we could not find a page that does not require an fsync()
|
|
** on the journal file then fsync the journal file. This is a
|
|
** very slow operation, so we work hard to avoid it. But sometimes
|
|
** it can't be helped.
|
|
*/
|
|
if( pPg==0 && pPager->pFirst && syncOk && !MEMDB){
|
|
int rc = syncJournal(pPager);
|
|
if( rc!=0 ){
|
|
return rc;
|
|
}
|
|
if( pPager->fullSync ){
|
|
/* If in full-sync mode, write a new journal header into the
|
|
** journal file. This is done to avoid ever modifying a journal
|
|
** header that is involved in the rollback of pages that have
|
|
** already been written to the database (in case the header is
|
|
** trashed when the nRec field is updated).
|
|
*/
|
|
pPager->nRec = 0;
|
|
assert( pPager->journalOff > 0 );
|
|
assert( pPager->doNotSync==0 );
|
|
rc = writeJournalHdr(pPager);
|
|
if( rc!=0 ){
|
|
return rc;
|
|
}
|
|
}
|
|
pPg = pPager->pFirst;
|
|
}
|
|
if( pPg==0 ){
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
assert( pPg->nRef==0 );
|
|
|
|
/* Write the page to the database file if it is dirty.
|
|
*/
|
|
if( pPg->dirty ){
|
|
int rc;
|
|
assert( pPg->needSync==0 );
|
|
makeClean(pPg);
|
|
pPg->dirty = 1;
|
|
pPg->pDirty = 0;
|
|
rc = pager_write_pagelist( pPg );
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}
|
|
assert( pPg->dirty==0 );
|
|
|
|
/* If the page we are recycling is marked as alwaysRollback, then
|
|
** set the global alwaysRollback flag, thus disabling the
|
|
** sqlite3PagerDontRollback() optimization for the rest of this transaction.
|
|
** It is necessary to do this because the page marked alwaysRollback
|
|
** might be reloaded at a later time but at that point we won't remember
|
|
** that is was marked alwaysRollback. This means that all pages must
|
|
** be marked as alwaysRollback from here on out.
|
|
*/
|
|
if( pPg->alwaysRollback ){
|
|
IOTRACE(("ALWAYS_ROLLBACK %p\n", pPager))
|
|
pPager->alwaysRollback = 1;
|
|
}
|
|
|
|
/* Unlink the old page from the free list and the hash table
|
|
*/
|
|
unlinkPage(pPg);
|
|
assert( pPg->pgno==0 );
|
|
|
|
*ppPg = pPg;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** This function is called to free superfluous dynamically allocated memory
|
|
** held by the pager system. Memory in use by any SQLite pager allocated
|
|
** by the current thread may be sqliteFree()ed.
|
|
**
|
|
** nReq is the number of bytes of memory required. Once this much has
|
|
** been released, the function returns. A negative value for nReq means
|
|
** free as much memory as possible. The return value is the total number
|
|
** of bytes of memory released.
|
|
*/
|
|
#if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) && !defined(SQLITE_OMIT_DISKIO)
|
|
int sqlite3PagerReleaseMemory(int nReq){
|
|
const ThreadData *pTsdro = sqlite3ThreadDataReadOnly();
|
|
int nReleased = 0;
|
|
int i;
|
|
|
|
/* If the the global mutex is held, this subroutine becomes a
|
|
** o-op; zero bytes of memory are freed. This is because
|
|
** some of the code invoked by this function may also
|
|
** try to obtain the mutex, resulting in a deadlock.
|
|
*/
|
|
if( sqlite3OsInMutex(0) ){
|
|
return 0;
|
|
}
|
|
|
|
/* Outermost loop runs for at most two iterations. First iteration we
|
|
** try to find memory that can be released without calling fsync(). Second
|
|
** iteration (which only runs if the first failed to free nReq bytes of
|
|
** memory) is permitted to call fsync(). This is of course much more
|
|
** expensive.
|
|
*/
|
|
for(i=0; i<=1; i++){
|
|
|
|
/* Loop through all the SQLite pagers opened by the current thread. */
|
|
Pager *pPager = pTsdro->pPager;
|
|
for( ; pPager && (nReq<0 || nReleased<nReq); pPager=pPager->pNext){
|
|
PgHdr *pPg;
|
|
int rc;
|
|
|
|
if( MEMDB ){
|
|
continue;
|
|
}
|
|
|
|
/* For each pager, try to free as many pages as possible (without
|
|
** calling fsync() if this is the first iteration of the outermost
|
|
** loop).
|
|
*/
|
|
while( SQLITE_OK==(rc = pager_recycle(pPager, i, &pPg)) && pPg) {
|
|
/* We've found a page to free. At this point the page has been
|
|
** removed from the page hash-table, free-list and synced-list
|
|
** (pFirstSynced). It is still in the all pages (pAll) list.
|
|
** Remove it from this list before freeing.
|
|
**
|
|
** Todo: Check the Pager.pStmt list to make sure this is Ok. It
|
|
** probably is though.
|
|
*/
|
|
PgHdr *pTmp;
|
|
assert( pPg );
|
|
if( pPg==pPager->pAll ){
|
|
pPager->pAll = pPg->pNextAll;
|
|
}else{
|
|
for( pTmp=pPager->pAll; pTmp->pNextAll!=pPg; pTmp=pTmp->pNextAll ){}
|
|
pTmp->pNextAll = pPg->pNextAll;
|
|
}
|
|
nReleased += sqliteAllocSize(pPg);
|
|
IOTRACE(("PGFREE %p %d\n", pPager, pPg->pgno));
|
|
PAGER_INCR(sqlite3_pager_pgfree_count);
|
|
sqliteFree(pPg);
|
|
}
|
|
|
|
if( rc!=SQLITE_OK ){
|
|
/* An error occured whilst writing to the database file or
|
|
** journal in pager_recycle(). The error is not returned to the
|
|
** caller of this function. Instead, set the Pager.errCode variable.
|
|
** The error will be returned to the user (or users, in the case
|
|
** of a shared pager cache) of the pager for which the error occured.
|
|
*/
|
|
assert( (rc&0xff)==SQLITE_IOERR || rc==SQLITE_FULL );
|
|
assert( pPager->state>=PAGER_RESERVED );
|
|
pager_error(pPager, rc);
|
|
}
|
|
}
|
|
}
|
|
|
|
return nReleased;
|
|
}
|
|
#endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT && !SQLITE_OMIT_DISKIO */
|
|
|
|
/*
|
|
** Read the content of page pPg out of the database file.
|
|
*/
|
|
static int readDbPage(Pager *pPager, PgHdr *pPg, Pgno pgno){
|
|
int rc;
|
|
assert( MEMDB==0 );
|
|
rc = sqlite3OsSeek(pPager->fd, (pgno-1)*(i64)pPager->pageSize);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg),
|
|
pPager->pageSize);
|
|
}
|
|
PAGER_INCR(sqlite3_pager_readdb_count);
|
|
PAGER_INCR(pPager->nRead);
|
|
IOTRACE(("PGIN %p %d\n", pPager, pgno));
|
|
if( pgno==1 ){
|
|
memcpy(&pPager->dbFileVers, &((u8*)PGHDR_TO_DATA(pPg))[24],
|
|
sizeof(pPager->dbFileVers));
|
|
}
|
|
CODEC1(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
|
|
PAGERTRACE4("FETCH %d page %d hash(%08x)\n",
|
|
PAGERID(pPager), pPg->pgno, pager_pagehash(pPg));
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** This function is called to obtain the shared lock required before
|
|
** data may be read from the pager cache. If the shared lock has already
|
|
** been obtained, this function is a no-op.
|
|
**
|
|
** Immediately after obtaining the shared lock (if required), this function
|
|
** checks for a hot-journal file. If one is found, an emergency rollback
|
|
** is performed immediately.
|
|
*/
|
|
static int pagerSharedLock(Pager *pPager){
|
|
int rc = SQLITE_OK;
|
|
|
|
if( pPager->state==PAGER_UNLOCK ){
|
|
if( !MEMDB ){
|
|
assert( pPager->nRef==0 );
|
|
if( !pPager->noReadlock ){
|
|
rc = pager_wait_on_lock(pPager, SHARED_LOCK);
|
|
if( rc!=SQLITE_OK ){
|
|
return pager_error(pPager, rc);
|
|
}
|
|
assert( pPager->state>=SHARED_LOCK );
|
|
}
|
|
|
|
/* If a journal file exists, and there is no RESERVED lock on the
|
|
** database file, then it either needs to be played back or deleted.
|
|
*/
|
|
if( hasHotJournal(pPager) ){
|
|
/* Get an EXCLUSIVE lock on the database file. At this point it is
|
|
** important that a RESERVED lock is not obtained on the way to the
|
|
** EXCLUSIVE lock. If it were, another process might open the
|
|
** database file, detect the RESERVED lock, and conclude that the
|
|
** database is safe to read while this process is still rolling it
|
|
** back.
|
|
**
|
|
** Because the intermediate RESERVED lock is not requested, the
|
|
** second process will get to this point in the code and fail to
|
|
** obtain it's own EXCLUSIVE lock on the database file.
|
|
*/
|
|
rc = sqlite3OsLock(pPager->fd, EXCLUSIVE_LOCK);
|
|
if( rc!=SQLITE_OK ){
|
|
pager_unlock(pPager);
|
|
return pager_error(pPager, rc);
|
|
}
|
|
pPager->state = PAGER_EXCLUSIVE;
|
|
|
|
/* Open the journal for reading only. Return SQLITE_BUSY if
|
|
** we are unable to open the journal file.
|
|
**
|
|
** The journal file does not need to be locked itself. The
|
|
** journal file is never open unless the main database file holds
|
|
** a write lock, so there is never any chance of two or more
|
|
** processes opening the journal at the same time.
|
|
**
|
|
** Open the journal for read/write access. This is because in
|
|
** exclusive-access mode the file descriptor will be kept open and
|
|
** possibly used for a transaction later on. On some systems, the
|
|
** OsTruncate() call used in exclusive-access mode also requires
|
|
** a read/write file handle.
|
|
*/
|
|
rc = SQLITE_BUSY;
|
|
if( sqlite3OsFileExists(pPager->zJournal) ){
|
|
int ro;
|
|
assert( !pPager->tempFile );
|
|
rc = sqlite3OsOpenReadWrite(pPager->zJournal, &pPager->jfd, &ro);
|
|
assert( rc!=SQLITE_OK || pPager->jfd );
|
|
if( ro ){
|
|
rc = SQLITE_BUSY;
|
|
sqlite3OsClose(&pPager->jfd);
|
|
}
|
|
}
|
|
if( rc!=SQLITE_OK ){
|
|
pager_unlock(pPager);
|
|
return SQLITE_BUSY;
|
|
}
|
|
pPager->journalOpen = 1;
|
|
pPager->journalStarted = 0;
|
|
pPager->journalOff = 0;
|
|
pPager->setMaster = 0;
|
|
pPager->journalHdr = 0;
|
|
|
|
/* Playback and delete the journal. Drop the database write
|
|
** lock and reacquire the read lock.
|
|
*/
|
|
rc = pager_playback(pPager, 1);
|
|
if( rc!=SQLITE_OK ){
|
|
return pager_error(pPager, rc);
|
|
}
|
|
assert(pPager->state==PAGER_SHARED ||
|
|
(pPager->exclusiveMode && pPager->state>PAGER_SHARED)
|
|
);
|
|
}
|
|
|
|
if( pPager->pAll ){
|
|
/* The shared-lock has just been acquired on the database file
|
|
** and there are already pages in the cache (from a previous
|
|
** read or write transaction). Check to see if the database
|
|
** has been modified. If the database has changed, flush the
|
|
** cache.
|
|
**
|
|
** Database changes is detected by looking at 15 bytes beginning
|
|
** at offset 24 into the file. The first 4 of these 16 bytes are
|
|
** a 32-bit counter that is incremented with each change. The
|
|
** other bytes change randomly with each file change when
|
|
** a codec is in use.
|
|
**
|
|
** There is a vanishingly small chance that a change will not be
|
|
** detected. The chance of an undetected change is so small that
|
|
** it can be neglected.
|
|
*/
|
|
char dbFileVers[sizeof(pPager->dbFileVers)];
|
|
sqlite3PagerPagecount(pPager);
|
|
|
|
if( pPager->errCode ){
|
|
return pPager->errCode;
|
|
}
|
|
|
|
if( pPager->dbSize>0 ){
|
|
IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
|
|
rc = sqlite3OsSeek(pPager->fd, 24);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers));
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
}else{
|
|
memset(dbFileVers, 0, sizeof(dbFileVers));
|
|
}
|
|
|
|
if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
|
|
pager_reset(pPager);
|
|
}
|
|
}
|
|
}
|
|
assert( pPager->exclusiveMode || pPager->state<=PAGER_SHARED );
|
|
if( pPager->state==PAGER_UNLOCK ){
|
|
pPager->state = PAGER_SHARED;
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Allocate a PgHdr object. Either create a new one or reuse
|
|
** an existing one that is not otherwise in use.
|
|
**
|
|
** A new PgHdr structure is created if any of the following are
|
|
** true:
|
|
**
|
|
** (1) We have not exceeded our maximum allocated cache size
|
|
** as set by the "PRAGMA cache_size" command.
|
|
**
|
|
** (2) There are no unused PgHdr objects available at this time.
|
|
**
|
|
** (3) This is an in-memory database.
|
|
**
|
|
** (4) There are no PgHdr objects that do not require a journal
|
|
** file sync and a sync of the journal file is currently
|
|
** prohibited.
|
|
**
|
|
** Otherwise, reuse an existing PgHdr. In other words, reuse an
|
|
** existing PgHdr if all of the following are true:
|
|
**
|
|
** (1) We have reached or exceeded the maximum cache size
|
|
** allowed by "PRAGMA cache_size".
|
|
**
|
|
** (2) There is a PgHdr available with PgHdr->nRef==0
|
|
**
|
|
** (3) We are not in an in-memory database
|
|
**
|
|
** (4) Either there is an available PgHdr that does not need
|
|
** to be synced to disk or else disk syncing is currently
|
|
** allowed.
|
|
*/
|
|
static int pagerAllocatePage(Pager *pPager, PgHdr **ppPg){
|
|
int rc = SQLITE_OK;
|
|
PgHdr *pPg;
|
|
|
|
/* Create a new PgHdr if any of the four conditions defined
|
|
** above is met: */
|
|
if( pPager->nPage<pPager->mxPage
|
|
|| pPager->pFirst==0
|
|
|| MEMDB
|
|
|| (pPager->pFirstSynced==0 && pPager->doNotSync)
|
|
){
|
|
if( pPager->nPage>=pPager->nHash ){
|
|
pager_resize_hash_table(pPager,
|
|
pPager->nHash<256 ? 256 : pPager->nHash*2);
|
|
if( pPager->nHash==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
goto pager_allocate_out;
|
|
}
|
|
}
|
|
pPg = sqliteMallocRaw( sizeof(*pPg) + pPager->pageSize
|
|
+ sizeof(u32) + pPager->nExtra
|
|
+ MEMDB*sizeof(PgHistory) );
|
|
if( pPg==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
goto pager_allocate_out;
|
|
}
|
|
memset(pPg, 0, sizeof(*pPg));
|
|
if( MEMDB ){
|
|
memset(PGHDR_TO_HIST(pPg, pPager), 0, sizeof(PgHistory));
|
|
}
|
|
pPg->pPager = pPager;
|
|
pPg->pNextAll = pPager->pAll;
|
|
pPager->pAll = pPg;
|
|
pPager->nPage++;
|
|
}else{
|
|
/* Recycle an existing page with a zero ref-count. */
|
|
rc = pager_recycle(pPager, 1, &pPg);
|
|
if( rc==SQLITE_BUSY ){
|
|
rc = SQLITE_IOERR_BLOCKED;
|
|
}
|
|
if( rc!=SQLITE_OK ){
|
|
goto pager_allocate_out;
|
|
}
|
|
assert( pPager->state>=SHARED_LOCK );
|
|
assert(pPg);
|
|
}
|
|
*ppPg = pPg;
|
|
|
|
pager_allocate_out:
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Make sure we have the content for a page. If the page was
|
|
** previously acquired with noContent==1, then the content was
|
|
** just initialized to zeros instead of being read from disk.
|
|
** But now we need the real data off of disk. So make sure we
|
|
** have it. Read it in if we do not have it already.
|
|
*/
|
|
static int pager_get_content(PgHdr *pPg){
|
|
if( pPg->needRead ){
|
|
int rc = readDbPage(pPg->pPager, pPg, pPg->pgno);
|
|
if( rc==SQLITE_OK ){
|
|
pPg->needRead = 0;
|
|
}else{
|
|
return rc;
|
|
}
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Acquire a page.
|
|
**
|
|
** A read lock on the disk file is obtained when the first page is acquired.
|
|
** This read lock is dropped when the last page is released.
|
|
**
|
|
** This routine works for any page number greater than 0. If the database
|
|
** file is smaller than the requested page, then no actual disk
|
|
** read occurs and the memory image of the page is initialized to
|
|
** all zeros. The extra data appended to a page is always initialized
|
|
** to zeros the first time a page is loaded into memory.
|
|
**
|
|
** The acquisition might fail for several reasons. In all cases,
|
|
** an appropriate error code is returned and *ppPage is set to NULL.
|
|
**
|
|
** See also sqlite3PagerLookup(). Both this routine and Lookup() attempt
|
|
** to find a page in the in-memory cache first. If the page is not already
|
|
** in memory, this routine goes to disk to read it in whereas Lookup()
|
|
** just returns 0. This routine acquires a read-lock the first time it
|
|
** has to go to disk, and could also playback an old journal if necessary.
|
|
** Since Lookup() never goes to disk, it never has to deal with locks
|
|
** or journal files.
|
|
**
|
|
** If noContent is false, the page contents are actually read from disk.
|
|
** If noContent is true, it means that we do not care about the contents
|
|
** of the page at this time, so do not do a disk read. Just fill in the
|
|
** page content with zeros. But mark the fact that we have not read the
|
|
** content by setting the PgHdr.needRead flag. Later on, if
|
|
** sqlite3PagerWrite() is called on this page or if this routine is
|
|
** called again with noContent==0, that means that the content is needed
|
|
** and the disk read should occur at that point.
|
|
*/
|
|
int sqlite3PagerAcquire(
|
|
Pager *pPager, /* The pager open on the database file */
|
|
Pgno pgno, /* Page number to fetch */
|
|
DbPage **ppPage, /* Write a pointer to the page here */
|
|
int noContent /* Do not bother reading content from disk if true */
|
|
){
|
|
PgHdr *pPg;
|
|
int rc;
|
|
|
|
assert( pPager->state==PAGER_UNLOCK || pPager->nRef>0 || pgno==1 );
|
|
|
|
/* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
|
|
** number greater than this, or zero, is requested.
|
|
*/
|
|
if( pgno>PAGER_MAX_PGNO || pgno==0 || pgno==PAGER_MJ_PGNO(pPager) ){
|
|
return SQLITE_CORRUPT_BKPT;
|
|
}
|
|
|
|
/* Make sure we have not hit any critical errors.
|
|
*/
|
|
assert( pPager!=0 );
|
|
*ppPage = 0;
|
|
if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
|
|
return pPager->errCode;
|
|
}
|
|
|
|
/* If this is the first page accessed, then get a SHARED lock
|
|
** on the database file. pagerSharedLock() is a no-op if
|
|
** a database lock is already held.
|
|
*/
|
|
rc = pagerSharedLock(pPager);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
assert( pPager->state!=PAGER_UNLOCK );
|
|
|
|
pPg = pager_lookup(pPager, pgno);
|
|
if( pPg==0 ){
|
|
/* The requested page is not in the page cache. */
|
|
int nMax;
|
|
int h;
|
|
PAGER_INCR(pPager->nMiss);
|
|
rc = pagerAllocatePage(pPager, &pPg);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
pPg->pgno = pgno;
|
|
assert( !MEMDB || pgno>pPager->stmtSize );
|
|
if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
|
|
sqlite3CheckMemory(pPager->aInJournal, pgno/8);
|
|
assert( pPager->journalOpen );
|
|
pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0;
|
|
pPg->needSync = 0;
|
|
}else{
|
|
pPg->inJournal = 0;
|
|
pPg->needSync = 0;
|
|
}
|
|
|
|
makeClean(pPg);
|
|
pPg->nRef = 1;
|
|
REFINFO(pPg);
|
|
|
|
pPager->nRef++;
|
|
if( pPager->nExtra>0 ){
|
|
memset(PGHDR_TO_EXTRA(pPg, pPager), 0, pPager->nExtra);
|
|
}
|
|
nMax = sqlite3PagerPagecount(pPager);
|
|
if( pPager->errCode ){
|
|
sqlite3PagerUnref(pPg);
|
|
rc = pPager->errCode;
|
|
return rc;
|
|
}
|
|
|
|
/* Populate the page with data, either by reading from the database
|
|
** file, or by setting the entire page to zero.
|
|
*/
|
|
if( nMax<(int)pgno || MEMDB || (noContent && !pPager->alwaysRollback) ){
|
|
if( pgno>pPager->mxPgno ){
|
|
sqlite3PagerUnref(pPg);
|
|
return SQLITE_FULL;
|
|
}
|
|
memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
|
|
pPg->needRead = noContent && !pPager->alwaysRollback;
|
|
IOTRACE(("ZERO %p %d\n", pPager, pgno));
|
|
}else{
|
|
rc = readDbPage(pPager, pPg, pgno);
|
|
if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
|
|
pPg->pgno = 0;
|
|
sqlite3PagerUnref(pPg);
|
|
return rc;
|
|
}
|
|
pPg->needRead = 0;
|
|
}
|
|
|
|
/* Link the page into the page hash table */
|
|
h = pgno & (pPager->nHash-1);
|
|
assert( pgno!=0 );
|
|
pPg->pNextHash = pPager->aHash[h];
|
|
pPager->aHash[h] = pPg;
|
|
if( pPg->pNextHash ){
|
|
assert( pPg->pNextHash->pPrevHash==0 );
|
|
pPg->pNextHash->pPrevHash = pPg;
|
|
}
|
|
|
|
#ifdef SQLITE_CHECK_PAGES
|
|
pPg->pageHash = pager_pagehash(pPg);
|
|
#endif
|
|
}else{
|
|
/* The requested page is in the page cache. */
|
|
assert(pPager->nRef>0 || pgno==1);
|
|
PAGER_INCR(pPager->nHit);
|
|
if( !noContent ){
|
|
rc = pager_get_content(pPg);
|
|
if( rc ){
|
|
return rc;
|
|
}
|
|
}
|
|
page_ref(pPg);
|
|
}
|
|
*ppPage = pPg;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Acquire a page if it is already in the in-memory cache. Do
|
|
** not read the page from disk. Return a pointer to the page,
|
|
** or 0 if the page is not in cache.
|
|
**
|
|
** See also sqlite3PagerGet(). The difference between this routine
|
|
** and sqlite3PagerGet() is that _get() will go to the disk and read
|
|
** in the page if the page is not already in cache. This routine
|
|
** returns NULL if the page is not in cache or if a disk I/O error
|
|
** has ever happened.
|
|
*/
|
|
DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
|
|
PgHdr *pPg;
|
|
|
|
assert( pPager!=0 );
|
|
assert( pgno!=0 );
|
|
|
|
if( pPager->state==PAGER_UNLOCK ){
|
|
assert( !pPager->pAll || pPager->exclusiveMode );
|
|
return 0;
|
|
}
|
|
if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
|
|
return 0;
|
|
}
|
|
pPg = pager_lookup(pPager, pgno);
|
|
if( pPg==0 ) return 0;
|
|
page_ref(pPg);
|
|
return pPg;
|
|
}
|
|
|
|
/*
|
|
** Release a page.
|
|
**
|
|
** If the number of references to the page drop to zero, then the
|
|
** page is added to the LRU list. When all references to all pages
|
|
** are released, a rollback occurs and the lock on the database is
|
|
** removed.
|
|
*/
|
|
int sqlite3PagerUnref(DbPage *pPg){
|
|
|
|
/* Decrement the reference count for this page
|
|
*/
|
|
assert( pPg->nRef>0 );
|
|
pPg->nRef--;
|
|
REFINFO(pPg);
|
|
|
|
CHECK_PAGE(pPg);
|
|
|
|
/* When the number of references to a page reach 0, call the
|
|
** destructor and add the page to the freelist.
|
|
*/
|
|
if( pPg->nRef==0 ){
|
|
Pager *pPager;
|
|
pPager = pPg->pPager;
|
|
pPg->pNextFree = 0;
|
|
pPg->pPrevFree = pPager->pLast;
|
|
pPager->pLast = pPg;
|
|
if( pPg->pPrevFree ){
|
|
pPg->pPrevFree->pNextFree = pPg;
|
|
}else{
|
|
pPager->pFirst = pPg;
|
|
}
|
|
if( pPg->needSync==0 && pPager->pFirstSynced==0 ){
|
|
pPager->pFirstSynced = pPg;
|
|
}
|
|
if( pPager->xDestructor ){
|
|
pPager->xDestructor(pPg, pPager->pageSize);
|
|
}
|
|
|
|
/* When all pages reach the freelist, drop the read lock from
|
|
** the database file.
|
|
*/
|
|
pPager->nRef--;
|
|
assert( pPager->nRef>=0 );
|
|
if( pPager->nRef==0 && (!pPager->exclusiveMode || pPager->journalOff>0) ){
|
|
pagerUnlockAndRollback(pPager);
|
|
}
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Create a journal file for pPager. There should already be a RESERVED
|
|
** or EXCLUSIVE lock on the database file when this routine is called.
|
|
**
|
|
** Return SQLITE_OK if everything. Return an error code and release the
|
|
** write lock if anything goes wrong.
|
|
*/
|
|
static int pager_open_journal(Pager *pPager){
|
|
int rc;
|
|
assert( !MEMDB );
|
|
assert( pPager->state>=PAGER_RESERVED );
|
|
assert( pPager->journalOpen==0 );
|
|
assert( pPager->useJournal );
|
|
assert( pPager->aInJournal==0 );
|
|
sqlite3PagerPagecount(pPager);
|
|
pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
|
|
if( pPager->aInJournal==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
goto failed_to_open_journal;
|
|
}
|
|
rc = sqlite3OsOpenExclusive(pPager->zJournal, &pPager->jfd,
|
|
pPager->tempFile);
|
|
assert( rc!=SQLITE_OK || pPager->jfd );
|
|
pPager->journalOff = 0;
|
|
pPager->setMaster = 0;
|
|
pPager->journalHdr = 0;
|
|
if( rc!=SQLITE_OK ){
|
|
if( rc==SQLITE_NOMEM ){
|
|
sqlite3OsDelete(pPager->zJournal);
|
|
}
|
|
goto failed_to_open_journal;
|
|
}
|
|
sqlite3OsSetFullSync(pPager->jfd, pPager->full_fsync);
|
|
sqlite3OsSetFullSync(pPager->fd, pPager->full_fsync);
|
|
sqlite3OsOpenDirectory(pPager->jfd, pPager->zDirectory);
|
|
pPager->journalOpen = 1;
|
|
pPager->journalStarted = 0;
|
|
pPager->needSync = 0;
|
|
pPager->alwaysRollback = 0;
|
|
pPager->nRec = 0;
|
|
if( pPager->errCode ){
|
|
rc = pPager->errCode;
|
|
goto failed_to_open_journal;
|
|
}
|
|
pPager->origDbSize = pPager->dbSize;
|
|
|
|
rc = writeJournalHdr(pPager);
|
|
|
|
if( pPager->stmtAutoopen && rc==SQLITE_OK ){
|
|
rc = sqlite3PagerStmtBegin(pPager);
|
|
}
|
|
if( rc!=SQLITE_OK && rc!=SQLITE_NOMEM ){
|
|
rc = pager_end_transaction(pPager);
|
|
if( rc==SQLITE_OK ){
|
|
rc = SQLITE_FULL;
|
|
}
|
|
}
|
|
return rc;
|
|
|
|
failed_to_open_journal:
|
|
sqliteFree(pPager->aInJournal);
|
|
pPager->aInJournal = 0;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Acquire a write-lock on the database. The lock is removed when
|
|
** the any of the following happen:
|
|
**
|
|
** * sqlite3PagerCommitPhaseTwo() is called.
|
|
** * sqlite3PagerRollback() is called.
|
|
** * sqlite3PagerClose() is called.
|
|
** * sqlite3PagerUnref() is called to on every outstanding page.
|
|
**
|
|
** The first parameter to this routine is a pointer to any open page of the
|
|
** database file. Nothing changes about the page - it is used merely to
|
|
** acquire a pointer to the Pager structure and as proof that there is
|
|
** already a read-lock on the database.
|
|
**
|
|
** The second parameter indicates how much space in bytes to reserve for a
|
|
** master journal file-name at the start of the journal when it is created.
|
|
**
|
|
** A journal file is opened if this is not a temporary file. For temporary
|
|
** files, the opening of the journal file is deferred until there is an
|
|
** actual need to write to the journal.
|
|
**
|
|
** If the database is already reserved for writing, this routine is a no-op.
|
|
**
|
|
** If exFlag is true, go ahead and get an EXCLUSIVE lock on the file
|
|
** immediately instead of waiting until we try to flush the cache. The
|
|
** exFlag is ignored if a transaction is already active.
|
|
*/
|
|
int sqlite3PagerBegin(DbPage *pPg, int exFlag){
|
|
Pager *pPager = pPg->pPager;
|
|
int rc = SQLITE_OK;
|
|
assert( pPg->nRef>0 );
|
|
assert( pPager->state!=PAGER_UNLOCK );
|
|
if( pPager->state==PAGER_SHARED ){
|
|
assert( pPager->aInJournal==0 );
|
|
if( MEMDB ){
|
|
pPager->state = PAGER_EXCLUSIVE;
|
|
pPager->origDbSize = pPager->dbSize;
|
|
}else{
|
|
rc = sqlite3OsLock(pPager->fd, RESERVED_LOCK);
|
|
if( rc==SQLITE_OK ){
|
|
pPager->state = PAGER_RESERVED;
|
|
if( exFlag ){
|
|
rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
|
|
}
|
|
}
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
pPager->dirtyCache = 0;
|
|
PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
|
|
if( pPager->useJournal && !pPager->tempFile ){
|
|
rc = pager_open_journal(pPager);
|
|
}
|
|
}
|
|
}else if( pPager->journalOpen && pPager->journalOff==0 ){
|
|
/* This happens when the pager was in exclusive-access mode last
|
|
** time a (read or write) transaction was successfully concluded
|
|
** by this connection. Instead of deleting the journal file it was
|
|
** kept open and truncated to 0 bytes.
|
|
*/
|
|
assert( pPager->nRec==0 );
|
|
assert( pPager->origDbSize==0 );
|
|
assert( pPager->aInJournal==0 );
|
|
sqlite3PagerPagecount(pPager);
|
|
pPager->aInJournal = sqliteMalloc( pPager->dbSize/8 + 1 );
|
|
if( !pPager->aInJournal ){
|
|
rc = SQLITE_NOMEM;
|
|
}else{
|
|
pPager->origDbSize = pPager->dbSize;
|
|
rc = writeJournalHdr(pPager);
|
|
}
|
|
}
|
|
assert( !pPager->journalOpen || pPager->journalOff>0 || rc!=SQLITE_OK );
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Make a page dirty. Set its dirty flag and add it to the dirty
|
|
** page list.
|
|
*/
|
|
static void makeDirty(PgHdr *pPg){
|
|
if( pPg->dirty==0 ){
|
|
Pager *pPager = pPg->pPager;
|
|
pPg->dirty = 1;
|
|
pPg->pDirty = pPager->pDirty;
|
|
if( pPager->pDirty ){
|
|
pPager->pDirty->pPrevDirty = pPg;
|
|
}
|
|
pPg->pPrevDirty = 0;
|
|
pPager->pDirty = pPg;
|
|
}
|
|
}
|
|
|
|
/*
|
|
** Make a page clean. Clear its dirty bit and remove it from the
|
|
** dirty page list.
|
|
*/
|
|
static void makeClean(PgHdr *pPg){
|
|
if( pPg->dirty ){
|
|
pPg->dirty = 0;
|
|
if( pPg->pDirty ){
|
|
pPg->pDirty->pPrevDirty = pPg->pPrevDirty;
|
|
}
|
|
if( pPg->pPrevDirty ){
|
|
pPg->pPrevDirty->pDirty = pPg->pDirty;
|
|
}else{
|
|
pPg->pPager->pDirty = pPg->pDirty;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
** Mark a data page as writeable. The page is written into the journal
|
|
** if it is not there already. This routine must be called before making
|
|
** changes to a page.
|
|
**
|
|
** The first time this routine is called, the pager creates a new
|
|
** journal and acquires a RESERVED lock on the database. If the RESERVED
|
|
** lock could not be acquired, this routine returns SQLITE_BUSY. The
|
|
** calling routine must check for that return value and be careful not to
|
|
** change any page data until this routine returns SQLITE_OK.
|
|
**
|
|
** If the journal file could not be written because the disk is full,
|
|
** then this routine returns SQLITE_FULL and does an immediate rollback.
|
|
** All subsequent write attempts also return SQLITE_FULL until there
|
|
** is a call to sqlite3PagerCommit() or sqlite3PagerRollback() to
|
|
** reset.
|
|
*/
|
|
static int pager_write(PgHdr *pPg){
|
|
void *pData = PGHDR_TO_DATA(pPg);
|
|
Pager *pPager = pPg->pPager;
|
|
int rc = SQLITE_OK;
|
|
|
|
/* Check for errors
|
|
*/
|
|
if( pPager->errCode ){
|
|
return pPager->errCode;
|
|
}
|
|
if( pPager->readOnly ){
|
|
return SQLITE_PERM;
|
|
}
|
|
|
|
assert( !pPager->setMaster );
|
|
|
|
CHECK_PAGE(pPg);
|
|
|
|
/* If this page was previously acquired with noContent==1, that means
|
|
** we didn't really read in the content of the page. This can happen
|
|
** (for example) when the page is being moved to the freelist. But
|
|
** now we are (perhaps) moving the page off of the freelist for
|
|
** reuse and we need to know its original content so that content
|
|
** can be stored in the rollback journal. So do the read at this
|
|
** time.
|
|
*/
|
|
rc = pager_get_content(pPg);
|
|
if( rc ){
|
|
return rc;
|
|
}
|
|
|
|
/* Mark the page as dirty. If the page has already been written
|
|
** to the journal then we can return right away.
|
|
*/
|
|
makeDirty(pPg);
|
|
if( pPg->inJournal && (pageInStatement(pPg) || pPager->stmtInUse==0) ){
|
|
pPager->dirtyCache = 1;
|
|
}else{
|
|
|
|
/* If we get this far, it means that the page needs to be
|
|
** written to the transaction journal or the ckeckpoint journal
|
|
** or both.
|
|
**
|
|
** First check to see that the transaction journal exists and
|
|
** create it if it does not.
|
|
*/
|
|
assert( pPager->state!=PAGER_UNLOCK );
|
|
rc = sqlite3PagerBegin(pPg, 0);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
assert( pPager->state>=PAGER_RESERVED );
|
|
if( !pPager->journalOpen && pPager->useJournal ){
|
|
rc = pager_open_journal(pPager);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
}
|
|
assert( pPager->journalOpen || !pPager->useJournal );
|
|
pPager->dirtyCache = 1;
|
|
|
|
/* The transaction journal now exists and we have a RESERVED or an
|
|
** EXCLUSIVE lock on the main database file. Write the current page to
|
|
** the transaction journal if it is not there already.
|
|
*/
|
|
if( !pPg->inJournal && (pPager->useJournal || MEMDB) ){
|
|
if( (int)pPg->pgno <= pPager->origDbSize ){
|
|
int szPg;
|
|
if( MEMDB ){
|
|
PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
|
|
PAGERTRACE3("JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
|
|
assert( pHist->pOrig==0 );
|
|
pHist->pOrig = sqliteMallocRaw( pPager->pageSize );
|
|
if( pHist->pOrig ){
|
|
memcpy(pHist->pOrig, PGHDR_TO_DATA(pPg), pPager->pageSize);
|
|
}
|
|
}else{
|
|
u32 cksum, saved;
|
|
char *pData2, *pEnd;
|
|
/* We should never write to the journal file the page that
|
|
** contains the database locks. The following assert verifies
|
|
** that we do not. */
|
|
assert( pPg->pgno!=PAGER_MJ_PGNO(pPager) );
|
|
pData2 = CODEC2(pPager, pData, pPg->pgno, 7);
|
|
cksum = pager_cksum(pPager, (u8*)pData2);
|
|
pEnd = pData2 + pPager->pageSize;
|
|
pData2 -= 4;
|
|
saved = *(u32*)pEnd;
|
|
put32bits(pEnd, cksum);
|
|
szPg = pPager->pageSize+8;
|
|
put32bits(pData2, pPg->pgno);
|
|
rc = sqlite3OsWrite(pPager->jfd, pData2, szPg);
|
|
IOTRACE(("JOUT %p %d %lld %d\n", pPager, pPg->pgno,
|
|
pPager->journalOff, szPg));
|
|
PAGER_INCR(sqlite3_pager_writej_count);
|
|
pPager->journalOff += szPg;
|
|
PAGERTRACE5("JOURNAL %d page %d needSync=%d hash(%08x)\n",
|
|
PAGERID(pPager), pPg->pgno, pPg->needSync, pager_pagehash(pPg));
|
|
*(u32*)pEnd = saved;
|
|
|
|
/* An error has occured writing to the journal file. The
|
|
** transaction will be rolled back by the layer above.
|
|
*/
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
|
|
pPager->nRec++;
|
|
assert( pPager->aInJournal!=0 );
|
|
pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
|
|
pPg->needSync = !pPager->noSync;
|
|
if( pPager->stmtInUse ){
|
|
pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
|
|
}
|
|
}
|
|
}else{
|
|
pPg->needSync = !pPager->journalStarted && !pPager->noSync;
|
|
PAGERTRACE4("APPEND %d page %d needSync=%d\n",
|
|
PAGERID(pPager), pPg->pgno, pPg->needSync);
|
|
}
|
|
if( pPg->needSync ){
|
|
pPager->needSync = 1;
|
|
}
|
|
pPg->inJournal = 1;
|
|
}
|
|
|
|
/* If the statement journal is open and the page is not in it,
|
|
** then write the current page to the statement journal. Note that
|
|
** the statement journal format differs from the standard journal format
|
|
** in that it omits the checksums and the header.
|
|
*/
|
|
if( pPager->stmtInUse
|
|
&& !pageInStatement(pPg)
|
|
&& (int)pPg->pgno<=pPager->stmtSize
|
|
){
|
|
assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
|
|
if( MEMDB ){
|
|
PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
|
|
assert( pHist->pStmt==0 );
|
|
pHist->pStmt = sqliteMallocRaw( pPager->pageSize );
|
|
if( pHist->pStmt ){
|
|
memcpy(pHist->pStmt, PGHDR_TO_DATA(pPg), pPager->pageSize);
|
|
}
|
|
PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
|
|
page_add_to_stmt_list(pPg);
|
|
}else{
|
|
char *pData2 = CODEC2(pPager, pData, pPg->pgno, 7)-4;
|
|
put32bits(pData2, pPg->pgno);
|
|
rc = sqlite3OsWrite(pPager->stfd, pData2, pPager->pageSize+4);
|
|
PAGERTRACE3("STMT-JOURNAL %d page %d\n", PAGERID(pPager), pPg->pgno);
|
|
if( rc!=SQLITE_OK ){
|
|
return rc;
|
|
}
|
|
pPager->stmtNRec++;
|
|
assert( pPager->aInStmt!=0 );
|
|
pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Update the database size and return.
|
|
*/
|
|
assert( pPager->state>=PAGER_SHARED );
|
|
if( pPager->dbSize<(int)pPg->pgno ){
|
|
pPager->dbSize = pPg->pgno;
|
|
if( !MEMDB && pPager->dbSize==PENDING_BYTE/pPager->pageSize ){
|
|
pPager->dbSize++;
|
|
}
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** This function is used to mark a data-page as writable. It uses
|
|
** pager_write() to open a journal file (if it is not already open)
|
|
** and write the page *pData to the journal.
|
|
**
|
|
** The difference between this function and pager_write() is that this
|
|
** function also deals with the special case where 2 or more pages
|
|
** fit on a single disk sector. In this case all co-resident pages
|
|
** must have been written to the journal file before returning.
|
|
*/
|
|
int sqlite3PagerWrite(DbPage *pDbPage){
|
|
int rc = SQLITE_OK;
|
|
|
|
PgHdr *pPg = pDbPage;
|
|
Pager *pPager = pPg->pPager;
|
|
Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
|
|
|
|
if( !MEMDB && nPagePerSector>1 ){
|
|
Pgno nPageCount; /* Total number of pages in database file */
|
|
Pgno pg1; /* First page of the sector pPg is located on. */
|
|
int nPage; /* Number of pages starting at pg1 to journal */
|
|
int ii;
|
|
|
|
/* Set the doNotSync flag to 1. This is because we cannot allow a journal
|
|
** header to be written between the pages journaled by this function.
|
|
*/
|
|
assert( pPager->doNotSync==0 );
|
|
pPager->doNotSync = 1;
|
|
|
|
/* This trick assumes that both the page-size and sector-size are
|
|
** an integer power of 2. It sets variable pg1 to the identifier
|
|
** of the first page of the sector pPg is located on.
|
|
*/
|
|
pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1;
|
|
|
|
nPageCount = sqlite3PagerPagecount(pPager);
|
|
if( pPg->pgno>nPageCount ){
|
|
nPage = (pPg->pgno - pg1)+1;
|
|
}else if( (pg1+nPagePerSector-1)>nPageCount ){
|
|
nPage = nPageCount+1-pg1;
|
|
}else{
|
|
nPage = nPagePerSector;
|
|
}
|
|
assert(nPage>0);
|
|
assert(pg1<=pPg->pgno);
|
|
assert((pg1+nPage)>pPg->pgno);
|
|
|
|
for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){
|
|
Pgno pg = pg1+ii;
|
|
if( !pPager->aInJournal || pg==pPg->pgno ||
|
|
pg>pPager->origDbSize || !(pPager->aInJournal[pg/8]&(1<<(pg&7)))
|
|
) {
|
|
if( pg!=PAGER_MJ_PGNO(pPager) ){
|
|
PgHdr *pPage;
|
|
rc = sqlite3PagerGet(pPager, pg, &pPage);
|
|
if( rc==SQLITE_OK ){
|
|
rc = pager_write(pPage);
|
|
sqlite3PagerUnref(pPage);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
assert( pPager->doNotSync==1 );
|
|
pPager->doNotSync = 0;
|
|
}else{
|
|
rc = pager_write(pDbPage);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return TRUE if the page given in the argument was previously passed
|
|
** to sqlite3PagerWrite(). In other words, return TRUE if it is ok
|
|
** to change the content of the page.
|
|
*/
|
|
#ifndef NDEBUG
|
|
int sqlite3PagerIswriteable(DbPage *pPg){
|
|
return pPg->dirty;
|
|
}
|
|
#endif
|
|
|
|
#ifndef SQLITE_OMIT_VACUUM
|
|
/*
|
|
** Replace the content of a single page with the information in the third
|
|
** argument.
|
|
*/
|
|
int sqlite3PagerOverwrite(Pager *pPager, Pgno pgno, void *pData){
|
|
PgHdr *pPg;
|
|
int rc;
|
|
|
|
rc = sqlite3PagerGet(pPager, pgno, &pPg);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3PagerWrite(pPg);
|
|
if( rc==SQLITE_OK ){
|
|
memcpy(sqlite3PagerGetData(pPg), pData, pPager->pageSize);
|
|
}
|
|
sqlite3PagerUnref(pPg);
|
|
}
|
|
return rc;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** A call to this routine tells the pager that it is not necessary to
|
|
** write the information on page pPg back to the disk, even though
|
|
** that page might be marked as dirty.
|
|
**
|
|
** The overlying software layer calls this routine when all of the data
|
|
** on the given page is unused. The pager marks the page as clean so
|
|
** that it does not get written to disk.
|
|
**
|
|
** Tests show that this optimization, together with the
|
|
** sqlite3PagerDontRollback() below, more than double the speed
|
|
** of large INSERT operations and quadruple the speed of large DELETEs.
|
|
**
|
|
** When this routine is called, set the alwaysRollback flag to true.
|
|
** Subsequent calls to sqlite3PagerDontRollback() for the same page
|
|
** will thereafter be ignored. This is necessary to avoid a problem
|
|
** where a page with data is added to the freelist during one part of
|
|
** a transaction then removed from the freelist during a later part
|
|
** of the same transaction and reused for some other purpose. When it
|
|
** is first added to the freelist, this routine is called. When reused,
|
|
** the sqlite3PagerDontRollback() routine is called. But because the
|
|
** page contains critical data, we still need to be sure it gets
|
|
** rolled back in spite of the sqlite3PagerDontRollback() call.
|
|
*/
|
|
void sqlite3PagerDontWrite(DbPage *pDbPage){
|
|
PgHdr *pPg = pDbPage;
|
|
Pager *pPager = pPg->pPager;
|
|
|
|
if( MEMDB ) return;
|
|
pPg->alwaysRollback = 1;
|
|
if( pPg->dirty && !pPager->stmtInUse ){
|
|
assert( pPager->state>=PAGER_SHARED );
|
|
if( pPager->dbSize==(int)pPg->pgno && pPager->origDbSize<pPager->dbSize ){
|
|
/* If this pages is the last page in the file and the file has grown
|
|
** during the current transaction, then do NOT mark the page as clean.
|
|
** When the database file grows, we must make sure that the last page
|
|
** gets written at least once so that the disk file will be the correct
|
|
** size. If you do not write this page and the size of the file
|
|
** on the disk ends up being too small, that can lead to database
|
|
** corruption during the next transaction.
|
|
*/
|
|
}else{
|
|
PAGERTRACE3("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager));
|
|
IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno))
|
|
makeClean(pPg);
|
|
#ifdef SQLITE_CHECK_PAGES
|
|
pPg->pageHash = pager_pagehash(pPg);
|
|
#endif
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
** A call to this routine tells the pager that if a rollback occurs,
|
|
** it is not necessary to restore the data on the given page. This
|
|
** means that the pager does not have to record the given page in the
|
|
** rollback journal.
|
|
**
|
|
** If we have not yet actually read the content of this page (if
|
|
** the PgHdr.needRead flag is set) then this routine acts as a promise
|
|
** that we will never need to read the page content in the future.
|
|
** so the needRead flag can be cleared at this point.
|
|
*/
|
|
void sqlite3PagerDontRollback(DbPage *pPg){
|
|
Pager *pPager = pPg->pPager;
|
|
|
|
assert( pPager->state>=PAGER_RESERVED );
|
|
if( pPager->journalOpen==0 ) return;
|
|
if( pPg->alwaysRollback || pPager->alwaysRollback || MEMDB ) return;
|
|
if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
|
|
assert( pPager->aInJournal!=0 );
|
|
pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
|
|
pPg->inJournal = 1;
|
|
pPg->needRead = 0;
|
|
if( pPager->stmtInUse ){
|
|
pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
|
|
}
|
|
PAGERTRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
|
|
IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
|
|
}
|
|
if( pPager->stmtInUse
|
|
&& !pageInStatement(pPg)
|
|
&& (int)pPg->pgno<=pPager->stmtSize
|
|
){
|
|
assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
|
|
assert( pPager->aInStmt!=0 );
|
|
pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
** This routine is called to increment the database file change-counter,
|
|
** stored at byte 24 of the pager file.
|
|
*/
|
|
static int pager_incr_changecounter(Pager *pPager){
|
|
PgHdr *pPgHdr;
|
|
u32 change_counter;
|
|
int rc;
|
|
|
|
if( !pPager->changeCountDone ){
|
|
/* Open page 1 of the file for writing. */
|
|
rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
rc = sqlite3PagerWrite(pPgHdr);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
/* Increment the value just read and write it back to byte 24. */
|
|
change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
|
|
change_counter++;
|
|
put32bits(((char*)PGHDR_TO_DATA(pPgHdr))+24, change_counter);
|
|
/* Release the page reference. */
|
|
sqlite3PagerUnref(pPgHdr);
|
|
pPager->changeCountDone = 1;
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Sync the database file for the pager pPager. zMaster points to the name
|
|
** of a master journal file that should be written into the individual
|
|
** journal file. zMaster may be NULL, which is interpreted as no master
|
|
** journal (a single database transaction).
|
|
**
|
|
** This routine ensures that the journal is synced, all dirty pages written
|
|
** to the database file and the database file synced. The only thing that
|
|
** remains to commit the transaction is to delete the journal file (or
|
|
** master journal file if specified).
|
|
**
|
|
** Note that if zMaster==NULL, this does not overwrite a previous value
|
|
** passed to an sqlite3PagerCommitPhaseOne() call.
|
|
**
|
|
** If parameter nTrunc is non-zero, then the pager file is truncated to
|
|
** nTrunc pages (this is used by auto-vacuum databases).
|
|
*/
|
|
int sqlite3PagerCommitPhaseOne(Pager *pPager, const char *zMaster, Pgno nTrunc){
|
|
int rc = SQLITE_OK;
|
|
|
|
PAGERTRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n",
|
|
pPager->zFilename, zMaster, nTrunc);
|
|
|
|
/* If this is an in-memory db, or no pages have been written to, or this
|
|
** function has already been called, it is a no-op.
|
|
*/
|
|
if( pPager->state!=PAGER_SYNCED && !MEMDB && pPager->dirtyCache ){
|
|
PgHdr *pPg;
|
|
assert( pPager->journalOpen );
|
|
|
|
/* If a master journal file name has already been written to the
|
|
** journal file, then no sync is required. This happens when it is
|
|
** written, then the process fails to upgrade from a RESERVED to an
|
|
** EXCLUSIVE lock. The next time the process tries to commit the
|
|
** transaction the m-j name will have already been written.
|
|
*/
|
|
if( !pPager->setMaster ){
|
|
rc = pager_incr_changecounter(pPager);
|
|
if( rc!=SQLITE_OK ) goto sync_exit;
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( nTrunc!=0 ){
|
|
/* If this transaction has made the database smaller, then all pages
|
|
** being discarded by the truncation must be written to the journal
|
|
** file.
|
|
*/
|
|
Pgno i;
|
|
int iSkip = PAGER_MJ_PGNO(pPager);
|
|
for( i=nTrunc+1; i<=pPager->origDbSize; i++ ){
|
|
if( !(pPager->aInJournal[i/8] & (1<<(i&7))) && i!=iSkip ){
|
|
rc = sqlite3PagerGet(pPager, i, &pPg);
|
|
if( rc!=SQLITE_OK ) goto sync_exit;
|
|
rc = sqlite3PagerWrite(pPg);
|
|
sqlite3PagerUnref(pPg);
|
|
if( rc!=SQLITE_OK ) goto sync_exit;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
rc = writeMasterJournal(pPager, zMaster);
|
|
if( rc!=SQLITE_OK ) goto sync_exit;
|
|
rc = syncJournal(pPager);
|
|
if( rc!=SQLITE_OK ) goto sync_exit;
|
|
}
|
|
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
if( nTrunc!=0 ){
|
|
rc = sqlite3PagerTruncate(pPager, nTrunc);
|
|
if( rc!=SQLITE_OK ) goto sync_exit;
|
|
}
|
|
#endif
|
|
|
|
/* Write all dirty pages to the database file */
|
|
pPg = pager_get_all_dirty_pages(pPager);
|
|
rc = pager_write_pagelist(pPg);
|
|
if( rc!=SQLITE_OK ) goto sync_exit;
|
|
pPager->pDirty = 0;
|
|
|
|
/* Sync the database file. */
|
|
if( !pPager->noSync ){
|
|
rc = sqlite3OsSync(pPager->fd, 0);
|
|
}
|
|
IOTRACE(("DBSYNC %p\n", pPager))
|
|
|
|
pPager->state = PAGER_SYNCED;
|
|
}else if( MEMDB && nTrunc!=0 ){
|
|
rc = sqlite3PagerTruncate(pPager, nTrunc);
|
|
}
|
|
|
|
sync_exit:
|
|
if( rc==SQLITE_IOERR_BLOCKED ){
|
|
/* pager_incr_changecounter() may attempt to obtain an exclusive
|
|
* lock to spill the cache and return IOERR_BLOCKED. But since
|
|
* there is no chance the cache is inconsistent, it's
|
|
* better to return SQLITE_BUSY.
|
|
*/
|
|
rc = SQLITE_BUSY;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
|
|
/*
|
|
** Commit all changes to the database and release the write lock.
|
|
**
|
|
** If the commit fails for any reason, a rollback attempt is made
|
|
** and an error code is returned. If the commit worked, SQLITE_OK
|
|
** is returned.
|
|
*/
|
|
int sqlite3PagerCommitPhaseTwo(Pager *pPager){
|
|
int rc;
|
|
PgHdr *pPg;
|
|
|
|
if( pPager->errCode ){
|
|
return pPager->errCode;
|
|
}
|
|
if( pPager->state<PAGER_RESERVED ){
|
|
return SQLITE_ERROR;
|
|
}
|
|
PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
|
|
if( MEMDB ){
|
|
pPg = pager_get_all_dirty_pages(pPager);
|
|
while( pPg ){
|
|
PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
|
|
clearHistory(pHist);
|
|
pPg->dirty = 0;
|
|
pPg->inJournal = 0;
|
|
pHist->inStmt = 0;
|
|
pPg->needSync = 0;
|
|
pHist->pPrevStmt = pHist->pNextStmt = 0;
|
|
pPg = pPg->pDirty;
|
|
}
|
|
pPager->pDirty = 0;
|
|
#ifndef NDEBUG
|
|
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
|
|
PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
|
|
assert( !pPg->alwaysRollback );
|
|
assert( !pHist->pOrig );
|
|
assert( !pHist->pStmt );
|
|
}
|
|
#endif
|
|
pPager->pStmt = 0;
|
|
pPager->state = PAGER_SHARED;
|
|
return SQLITE_OK;
|
|
}
|
|
assert( pPager->journalOpen || !pPager->dirtyCache );
|
|
assert( pPager->state==PAGER_SYNCED || !pPager->dirtyCache );
|
|
rc = pager_end_transaction(pPager);
|
|
return pager_error(pPager, rc);
|
|
}
|
|
|
|
/*
|
|
** Rollback all changes. The database falls back to PAGER_SHARED mode.
|
|
** All in-memory cache pages revert to their original data contents.
|
|
** The journal is deleted.
|
|
**
|
|
** This routine cannot fail unless some other process is not following
|
|
** the correct locking protocol or unless some other
|
|
** process is writing trash into the journal file (SQLITE_CORRUPT) or
|
|
** unless a prior malloc() failed (SQLITE_NOMEM). Appropriate error
|
|
** codes are returned for all these occasions. Otherwise,
|
|
** SQLITE_OK is returned.
|
|
*/
|
|
int sqlite3PagerRollback(Pager *pPager){
|
|
int rc;
|
|
PAGERTRACE2("ROLLBACK %d\n", PAGERID(pPager));
|
|
if( MEMDB ){
|
|
PgHdr *p;
|
|
for(p=pPager->pAll; p; p=p->pNextAll){
|
|
PgHistory *pHist;
|
|
assert( !p->alwaysRollback );
|
|
if( !p->dirty ){
|
|
assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pOrig );
|
|
assert( !((PgHistory *)PGHDR_TO_HIST(p, pPager))->pStmt );
|
|
continue;
|
|
}
|
|
|
|
pHist = PGHDR_TO_HIST(p, pPager);
|
|
if( pHist->pOrig ){
|
|
memcpy(PGHDR_TO_DATA(p), pHist->pOrig, pPager->pageSize);
|
|
PAGERTRACE3("ROLLBACK-PAGE %d of %d\n", p->pgno, PAGERID(pPager));
|
|
}else{
|
|
PAGERTRACE3("PAGE %d is clean on %d\n", p->pgno, PAGERID(pPager));
|
|
}
|
|
clearHistory(pHist);
|
|
p->dirty = 0;
|
|
p->inJournal = 0;
|
|
pHist->inStmt = 0;
|
|
pHist->pPrevStmt = pHist->pNextStmt = 0;
|
|
if( pPager->xReiniter ){
|
|
pPager->xReiniter(p, pPager->pageSize);
|
|
}
|
|
}
|
|
pPager->pDirty = 0;
|
|
pPager->pStmt = 0;
|
|
pPager->dbSize = pPager->origDbSize;
|
|
pager_truncate_cache(pPager);
|
|
pPager->stmtInUse = 0;
|
|
pPager->state = PAGER_SHARED;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
if( !pPager->dirtyCache || !pPager->journalOpen ){
|
|
rc = pager_end_transaction(pPager);
|
|
return rc;
|
|
}
|
|
|
|
if( pPager->errCode && pPager->errCode!=SQLITE_FULL ){
|
|
if( pPager->state>=PAGER_EXCLUSIVE ){
|
|
pager_playback(pPager, 0);
|
|
}
|
|
return pPager->errCode;
|
|
}
|
|
if( pPager->state==PAGER_RESERVED ){
|
|
int rc2;
|
|
rc = pager_playback(pPager, 0);
|
|
rc2 = pager_end_transaction(pPager);
|
|
if( rc==SQLITE_OK ){
|
|
rc = rc2;
|
|
}
|
|
}else{
|
|
rc = pager_playback(pPager, 0);
|
|
}
|
|
/* pager_reset(pPager); */
|
|
pPager->dbSize = -1;
|
|
|
|
/* If an error occurs during a ROLLBACK, we can no longer trust the pager
|
|
** cache. So call pager_error() on the way out to make any error
|
|
** persistent.
|
|
*/
|
|
return pager_error(pPager, rc);
|
|
}
|
|
|
|
/*
|
|
** Return TRUE if the database file is opened read-only. Return FALSE
|
|
** if the database is (in theory) writable.
|
|
*/
|
|
int sqlite3PagerIsreadonly(Pager *pPager){
|
|
return pPager->readOnly;
|
|
}
|
|
|
|
/*
|
|
** Return the number of references to the pager.
|
|
*/
|
|
int sqlite3PagerRefcount(Pager *pPager){
|
|
return pPager->nRef;
|
|
}
|
|
|
|
#ifdef SQLITE_TEST
|
|
/*
|
|
** This routine is used for testing and analysis only.
|
|
*/
|
|
int *sqlite3PagerStats(Pager *pPager){
|
|
static int a[11];
|
|
a[0] = pPager->nRef;
|
|
a[1] = pPager->nPage;
|
|
a[2] = pPager->mxPage;
|
|
a[3] = pPager->dbSize;
|
|
a[4] = pPager->state;
|
|
a[5] = pPager->errCode;
|
|
a[6] = pPager->nHit;
|
|
a[7] = pPager->nMiss;
|
|
a[8] = 0; /* Used to be pPager->nOvfl */
|
|
a[9] = pPager->nRead;
|
|
a[10] = pPager->nWrite;
|
|
return a;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Set the statement rollback point.
|
|
**
|
|
** This routine should be called with the transaction journal already
|
|
** open. A new statement journal is created that can be used to rollback
|
|
** changes of a single SQL command within a larger transaction.
|
|
*/
|
|
int sqlite3PagerStmtBegin(Pager *pPager){
|
|
int rc;
|
|
assert( !pPager->stmtInUse );
|
|
assert( pPager->state>=PAGER_SHARED );
|
|
assert( pPager->dbSize>=0 );
|
|
PAGERTRACE2("STMT-BEGIN %d\n", PAGERID(pPager));
|
|
if( MEMDB ){
|
|
pPager->stmtInUse = 1;
|
|
pPager->stmtSize = pPager->dbSize;
|
|
return SQLITE_OK;
|
|
}
|
|
if( !pPager->journalOpen ){
|
|
pPager->stmtAutoopen = 1;
|
|
return SQLITE_OK;
|
|
}
|
|
assert( pPager->journalOpen );
|
|
pPager->aInStmt = sqliteMalloc( pPager->dbSize/8 + 1 );
|
|
if( pPager->aInStmt==0 ){
|
|
/* sqlite3OsLock(pPager->fd, SHARED_LOCK); */
|
|
return SQLITE_NOMEM;
|
|
}
|
|
#ifndef NDEBUG
|
|
rc = sqlite3OsFileSize(pPager->jfd, &pPager->stmtJSize);
|
|
if( rc ) goto stmt_begin_failed;
|
|
assert( pPager->stmtJSize == pPager->journalOff );
|
|
#endif
|
|
pPager->stmtJSize = pPager->journalOff;
|
|
pPager->stmtSize = pPager->dbSize;
|
|
pPager->stmtHdrOff = 0;
|
|
pPager->stmtCksum = pPager->cksumInit;
|
|
if( !pPager->stmtOpen ){
|
|
rc = sqlite3PagerOpentemp(&pPager->stfd);
|
|
if( rc ) goto stmt_begin_failed;
|
|
pPager->stmtOpen = 1;
|
|
pPager->stmtNRec = 0;
|
|
}
|
|
pPager->stmtInUse = 1;
|
|
return SQLITE_OK;
|
|
|
|
stmt_begin_failed:
|
|
if( pPager->aInStmt ){
|
|
sqliteFree(pPager->aInStmt);
|
|
pPager->aInStmt = 0;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Commit a statement.
|
|
*/
|
|
int sqlite3PagerStmtCommit(Pager *pPager){
|
|
if( pPager->stmtInUse ){
|
|
PgHdr *pPg, *pNext;
|
|
PAGERTRACE2("STMT-COMMIT %d\n", PAGERID(pPager));
|
|
if( !MEMDB ){
|
|
sqlite3OsSeek(pPager->stfd, 0);
|
|
/* sqlite3OsTruncate(pPager->stfd, 0); */
|
|
sqliteFree( pPager->aInStmt );
|
|
pPager->aInStmt = 0;
|
|
}else{
|
|
for(pPg=pPager->pStmt; pPg; pPg=pNext){
|
|
PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);
|
|
pNext = pHist->pNextStmt;
|
|
assert( pHist->inStmt );
|
|
pHist->inStmt = 0;
|
|
pHist->pPrevStmt = pHist->pNextStmt = 0;
|
|
sqliteFree(pHist->pStmt);
|
|
pHist->pStmt = 0;
|
|
}
|
|
}
|
|
pPager->stmtNRec = 0;
|
|
pPager->stmtInUse = 0;
|
|
pPager->pStmt = 0;
|
|
}
|
|
pPager->stmtAutoopen = 0;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Rollback a statement.
|
|
*/
|
|
int sqlite3PagerStmtRollback(Pager *pPager){
|
|
int rc;
|
|
if( pPager->stmtInUse ){
|
|
PAGERTRACE2("STMT-ROLLBACK %d\n", PAGERID(pPager));
|
|
if( MEMDB ){
|
|
PgHdr *pPg;
|
|
PgHistory *pHist;
|
|
for(pPg=pPager->pStmt; pPg; pPg=pHist->pNextStmt){
|
|
pHist = PGHDR_TO_HIST(pPg, pPager);
|
|
if( pHist->pStmt ){
|
|
memcpy(PGHDR_TO_DATA(pPg), pHist->pStmt, pPager->pageSize);
|
|
sqliteFree(pHist->pStmt);
|
|
pHist->pStmt = 0;
|
|
}
|
|
}
|
|
pPager->dbSize = pPager->stmtSize;
|
|
pager_truncate_cache(pPager);
|
|
rc = SQLITE_OK;
|
|
}else{
|
|
rc = pager_stmt_playback(pPager);
|
|
}
|
|
sqlite3PagerStmtCommit(pPager);
|
|
}else{
|
|
rc = SQLITE_OK;
|
|
}
|
|
pPager->stmtAutoopen = 0;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return the full pathname of the database file.
|
|
*/
|
|
const char *sqlite3PagerFilename(Pager *pPager){
|
|
return pPager->zFilename;
|
|
}
|
|
|
|
/*
|
|
** Return the directory of the database file.
|
|
*/
|
|
const char *sqlite3PagerDirname(Pager *pPager){
|
|
return pPager->zDirectory;
|
|
}
|
|
|
|
/*
|
|
** Return the full pathname of the journal file.
|
|
*/
|
|
const char *sqlite3PagerJournalname(Pager *pPager){
|
|
return pPager->zJournal;
|
|
}
|
|
|
|
/*
|
|
** Return true if fsync() calls are disabled for this pager. Return FALSE
|
|
** if fsync()s are executed normally.
|
|
*/
|
|
int sqlite3PagerNosync(Pager *pPager){
|
|
return pPager->noSync;
|
|
}
|
|
|
|
#ifdef SQLITE_HAS_CODEC
|
|
/*
|
|
** Set the codec for this pager
|
|
*/
|
|
void sqlite3PagerSetCodec(
|
|
Pager *pPager,
|
|
void *(*xCodec)(void*,void*,Pgno,int),
|
|
void *pCodecArg
|
|
){
|
|
pPager->xCodec = xCodec;
|
|
pPager->pCodecArg = pCodecArg;
|
|
}
|
|
#endif
|
|
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
/*
|
|
** Move the page pPg to location pgno in the file.
|
|
**
|
|
** There must be no references to the page previously located at
|
|
** pgno (which we call pPgOld) though that page is allowed to be
|
|
** in cache. If the page previous located at pgno is not already
|
|
** in the rollback journal, it is not put there by by this routine.
|
|
**
|
|
** References to the page pPg remain valid. Updating any
|
|
** meta-data associated with pPg (i.e. data stored in the nExtra bytes
|
|
** allocated along with the page) is the responsibility of the caller.
|
|
**
|
|
** A transaction must be active when this routine is called. It used to be
|
|
** required that a statement transaction was not active, but this restriction
|
|
** has been removed (CREATE INDEX needs to move a page when a statement
|
|
** transaction is active).
|
|
*/
|
|
int sqlite3PagerMovepage(Pager *pPager, DbPage *pPg, Pgno pgno){
|
|
PgHdr *pPgOld; /* The page being overwritten. */
|
|
int h;
|
|
Pgno needSyncPgno = 0;
|
|
|
|
assert( pPg->nRef>0 );
|
|
|
|
PAGERTRACE5("MOVE %d page %d (needSync=%d) moves to %d\n",
|
|
PAGERID(pPager), pPg->pgno, pPg->needSync, pgno);
|
|
IOTRACE(("MOVE %p %d %d\n", pPager, pPg->pgno, pgno))
|
|
|
|
pager_get_content(pPg);
|
|
if( pPg->needSync ){
|
|
needSyncPgno = pPg->pgno;
|
|
assert( pPg->inJournal || (int)pgno>pPager->origDbSize );
|
|
assert( pPg->dirty );
|
|
assert( pPager->needSync );
|
|
}
|
|
|
|
/* Unlink pPg from it's hash-chain */
|
|
unlinkHashChain(pPager, pPg);
|
|
|
|
/* If the cache contains a page with page-number pgno, remove it
|
|
** from it's hash chain. Also, if the PgHdr.needSync was set for
|
|
** page pgno before the 'move' operation, it needs to be retained
|
|
** for the page moved there.
|
|
*/
|
|
pPg->needSync = 0;
|
|
pPgOld = pager_lookup(pPager, pgno);
|
|
if( pPgOld ){
|
|
assert( pPgOld->nRef==0 );
|
|
unlinkHashChain(pPager, pPgOld);
|
|
makeClean(pPgOld);
|
|
pPg->needSync = pPgOld->needSync;
|
|
}else{
|
|
pPg->needSync = 0;
|
|
}
|
|
if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
|
|
pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0;
|
|
}else{
|
|
pPg->inJournal = 0;
|
|
assert( pPg->needSync==0 || (int)pgno>pPager->origDbSize );
|
|
}
|
|
|
|
/* Change the page number for pPg and insert it into the new hash-chain. */
|
|
assert( pgno!=0 );
|
|
pPg->pgno = pgno;
|
|
h = pgno & (pPager->nHash-1);
|
|
if( pPager->aHash[h] ){
|
|
assert( pPager->aHash[h]->pPrevHash==0 );
|
|
pPager->aHash[h]->pPrevHash = pPg;
|
|
}
|
|
pPg->pNextHash = pPager->aHash[h];
|
|
pPager->aHash[h] = pPg;
|
|
pPg->pPrevHash = 0;
|
|
|
|
makeDirty(pPg);
|
|
pPager->dirtyCache = 1;
|
|
|
|
if( needSyncPgno ){
|
|
/* If needSyncPgno is non-zero, then the journal file needs to be
|
|
** sync()ed before any data is written to database file page needSyncPgno.
|
|
** Currently, no such page exists in the page-cache and the
|
|
** Pager.aInJournal bit has been set. This needs to be remedied by loading
|
|
** the page into the pager-cache and setting the PgHdr.needSync flag.
|
|
**
|
|
** The sqlite3PagerGet() call may cause the journal to sync. So make
|
|
** sure the Pager.needSync flag is set too.
|
|
*/
|
|
int rc;
|
|
PgHdr *pPgHdr;
|
|
assert( pPager->needSync );
|
|
rc = sqlite3PagerGet(pPager, needSyncPgno, &pPgHdr);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
pPager->needSync = 1;
|
|
pPgHdr->needSync = 1;
|
|
pPgHdr->inJournal = 1;
|
|
makeDirty(pPgHdr);
|
|
sqlite3PagerUnref(pPgHdr);
|
|
}
|
|
|
|
return SQLITE_OK;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
** Return a pointer to the data for the specified page.
|
|
*/
|
|
void *sqlite3PagerGetData(DbPage *pPg){
|
|
return PGHDR_TO_DATA(pPg);
|
|
}
|
|
|
|
/*
|
|
** Return a pointer to the Pager.nExtra bytes of "extra" space
|
|
** allocated along with the specified page.
|
|
*/
|
|
void *sqlite3PagerGetExtra(DbPage *pPg){
|
|
Pager *pPager = pPg->pPager;
|
|
return (pPager?PGHDR_TO_EXTRA(pPg, pPager):0);
|
|
}
|
|
|
|
/*
|
|
** Get/set the locking-mode for this pager. Parameter eMode must be one
|
|
** of PAGER_LOCKINGMODE_QUERY, PAGER_LOCKINGMODE_NORMAL or
|
|
** PAGER_LOCKINGMODE_EXCLUSIVE. If the parameter is not _QUERY, then
|
|
** the locking-mode is set to the value specified.
|
|
**
|
|
** The returned value is either PAGER_LOCKINGMODE_NORMAL or
|
|
** PAGER_LOCKINGMODE_EXCLUSIVE, indicating the current (possibly updated)
|
|
** locking-mode.
|
|
*/
|
|
int sqlite3PagerLockingMode(Pager *pPager, int eMode){
|
|
assert( eMode==PAGER_LOCKINGMODE_QUERY
|
|
|| eMode==PAGER_LOCKINGMODE_NORMAL
|
|
|| eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
|
|
assert( PAGER_LOCKINGMODE_QUERY<0 );
|
|
assert( PAGER_LOCKINGMODE_NORMAL>=0 && PAGER_LOCKINGMODE_EXCLUSIVE>=0 );
|
|
if( eMode>=0 && !pPager->tempFile ){
|
|
pPager->exclusiveMode = eMode;
|
|
}
|
|
return (int)pPager->exclusiveMode;
|
|
}
|
|
|
|
#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
|
|
/*
|
|
** Return the current state of the file lock for the given pager.
|
|
** The return value is one of NO_LOCK, SHARED_LOCK, RESERVED_LOCK,
|
|
** PENDING_LOCK, or EXCLUSIVE_LOCK.
|
|
*/
|
|
int sqlite3PagerLockstate(Pager *pPager){
|
|
return sqlite3OsLockState(pPager->fd);
|
|
}
|
|
#endif
|
|
|
|
#ifdef SQLITE_DEBUG
|
|
/*
|
|
** Print a listing of all referenced pages and their ref count.
|
|
*/
|
|
void sqlite3PagerRefdump(Pager *pPager){
|
|
PgHdr *pPg;
|
|
for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
|
|
if( pPg->nRef<=0 ) continue;
|
|
sqlite3DebugPrintf("PAGE %3d addr=%p nRef=%d\n",
|
|
pPg->pgno, PGHDR_TO_DATA(pPg), pPg->nRef);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#endif /* SQLITE_OMIT_DISKIO */
|