9f6a67ba17
--HG-- extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%401209
589 lines
25 KiB
C
589 lines
25 KiB
C
/*
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** 2004 April 6
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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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** $Id$
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**
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** This file implements a external (disk-based) database using BTrees.
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** For a detailed discussion of BTrees, refer to
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**
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** Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
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** "Sorting And Searching", pages 473-480. Addison-Wesley
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** Publishing Company, Reading, Massachusetts.
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**
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** The basic idea is that each page of the file contains N database
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** entries and N+1 pointers to subpages.
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**
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** ----------------------------------------------------------------
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** | Ptr(0) | Key(0) | Ptr(1) | Key(1) | ... | Key(N-1) | Ptr(N) |
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** ----------------------------------------------------------------
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**
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** All of the keys on the page that Ptr(0) points to have values less
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** than Key(0). All of the keys on page Ptr(1) and its subpages have
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** values greater than Key(0) and less than Key(1). All of the keys
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** on Ptr(N) and its subpages have values greater than Key(N-1). And
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** so forth.
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**
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** Finding a particular key requires reading O(log(M)) pages from the
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** disk where M is the number of entries in the tree.
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**
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** In this implementation, a single file can hold one or more separate
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** BTrees. Each BTree is identified by the index of its root page. The
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** key and data for any entry are combined to form the "payload". A
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** fixed amount of payload can be carried directly on the database
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** page. If the payload is larger than the preset amount then surplus
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** bytes are stored on overflow pages. The payload for an entry
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** and the preceding pointer are combined to form a "Cell". Each
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** page has a small header which contains the Ptr(N) pointer and other
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** information such as the size of key and data.
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**
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** FORMAT DETAILS
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**
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** The file is divided into pages. The first page is called page 1,
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** the second is page 2, and so forth. A page number of zero indicates
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** "no such page". The page size can be anything between 512 and 65536.
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** Each page can be either a btree page, a freelist page or an overflow
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** page.
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**
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** The first page is always a btree page. The first 100 bytes of the first
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** page contain a special header (the "file header") that describes the file.
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** The format of the file header is as follows:
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**
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** OFFSET SIZE DESCRIPTION
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** 0 16 Header string: "SQLite format 3\000"
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** 16 2 Page size in bytes.
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** 18 1 File format write version
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** 19 1 File format read version
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** 20 1 Bytes of unused space at the end of each page
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** 21 1 Max embedded payload fraction
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** 22 1 Min embedded payload fraction
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** 23 1 Min leaf payload fraction
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** 24 4 File change counter
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** 28 4 Reserved for future use
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** 32 4 First freelist page
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** 36 4 Number of freelist pages in the file
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** 40 60 15 4-byte meta values passed to higher layers
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**
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** All of the integer values are big-endian (most significant byte first).
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**
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** The file change counter is incremented when the database is changed
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** This counter allows other processes to know when the file has changed
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** and thus when they need to flush their cache.
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**
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** The max embedded payload fraction is the amount of the total usable
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** space in a page that can be consumed by a single cell for standard
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** B-tree (non-LEAFDATA) tables. A value of 255 means 100%. The default
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** is to limit the maximum cell size so that at least 4 cells will fit
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** on one page. Thus the default max embedded payload fraction is 64.
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**
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** If the payload for a cell is larger than the max payload, then extra
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** payload is spilled to overflow pages. Once an overflow page is allocated,
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** as many bytes as possible are moved into the overflow pages without letting
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** the cell size drop below the min embedded payload fraction.
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**
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** The min leaf payload fraction is like the min embedded payload fraction
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** except that it applies to leaf nodes in a LEAFDATA tree. The maximum
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** payload fraction for a LEAFDATA tree is always 100% (or 255) and it
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** not specified in the header.
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**
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** Each btree pages is divided into three sections: The header, the
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** cell pointer array, and the cell content area. Page 1 also has a 100-byte
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** file header that occurs before the page header.
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**
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** |----------------|
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** | file header | 100 bytes. Page 1 only.
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** |----------------|
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** | page header | 8 bytes for leaves. 12 bytes for interior nodes
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** |----------------|
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** | cell pointer | | 2 bytes per cell. Sorted order.
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** | array | | Grows downward
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** | | v
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** |----------------|
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** | unallocated |
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** | space |
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** |----------------| ^ Grows upwards
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** | cell content | | Arbitrary order interspersed with freeblocks.
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** | area | | and free space fragments.
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** |----------------|
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**
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** The page headers looks like this:
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**
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** OFFSET SIZE DESCRIPTION
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** 0 1 Flags. 1: intkey, 2: zerodata, 4: leafdata, 8: leaf
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** 1 2 byte offset to the first freeblock
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** 3 2 number of cells on this page
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** 5 2 first byte of the cell content area
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** 7 1 number of fragmented free bytes
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** 8 4 Right child (the Ptr(N) value). Omitted on leaves.
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**
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** The flags define the format of this btree page. The leaf flag means that
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** this page has no children. The zerodata flag means that this page carries
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** only keys and no data. The intkey flag means that the key is a integer
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** which is stored in the key size entry of the cell header rather than in
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** the payload area.
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**
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** The cell pointer array begins on the first byte after the page header.
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** The cell pointer array contains zero or more 2-byte numbers which are
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** offsets from the beginning of the page to the cell content in the cell
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** content area. The cell pointers occur in sorted order. The system strives
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** to keep free space after the last cell pointer so that new cells can
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** be easily added without having to defragment the page.
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**
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** Cell content is stored at the very end of the page and grows toward the
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** beginning of the page.
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**
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** Unused space within the cell content area is collected into a linked list of
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** freeblocks. Each freeblock is at least 4 bytes in size. The byte offset
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** to the first freeblock is given in the header. Freeblocks occur in
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** increasing order. Because a freeblock must be at least 4 bytes in size,
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** any group of 3 or fewer unused bytes in the cell content area cannot
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** exist on the freeblock chain. A group of 3 or fewer free bytes is called
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** a fragment. The total number of bytes in all fragments is recorded.
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** in the page header at offset 7.
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**
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** SIZE DESCRIPTION
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** 2 Byte offset of the next freeblock
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** 2 Bytes in this freeblock
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**
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** Cells are of variable length. Cells are stored in the cell content area at
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** the end of the page. Pointers to the cells are in the cell pointer array
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** that immediately follows the page header. Cells is not necessarily
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** contiguous or in order, but cell pointers are contiguous and in order.
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**
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** Cell content makes use of variable length integers. A variable
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** length integer is 1 to 9 bytes where the lower 7 bits of each
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** byte are used. The integer consists of all bytes that have bit 8 set and
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** the first byte with bit 8 clear. The most significant byte of the integer
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** appears first. A variable-length integer may not be more than 9 bytes long.
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** As a special case, all 8 bytes of the 9th byte are used as data. This
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** allows a 64-bit integer to be encoded in 9 bytes.
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**
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** 0x00 becomes 0x00000000
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** 0x7f becomes 0x0000007f
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** 0x81 0x00 becomes 0x00000080
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** 0x82 0x00 becomes 0x00000100
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** 0x80 0x7f becomes 0x0000007f
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** 0x8a 0x91 0xd1 0xac 0x78 becomes 0x12345678
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** 0x81 0x81 0x81 0x81 0x01 becomes 0x10204081
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**
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** Variable length integers are used for rowids and to hold the number of
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** bytes of key and data in a btree cell.
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**
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** The content of a cell looks like this:
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**
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** SIZE DESCRIPTION
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** 4 Page number of the left child. Omitted if leaf flag is set.
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** var Number of bytes of data. Omitted if the zerodata flag is set.
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** var Number of bytes of key. Or the key itself if intkey flag is set.
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** * Payload
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** 4 First page of the overflow chain. Omitted if no overflow
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**
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** Overflow pages form a linked list. Each page except the last is completely
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** filled with data (pagesize - 4 bytes). The last page can have as little
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** as 1 byte of data.
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**
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** SIZE DESCRIPTION
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** 4 Page number of next overflow page
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** * Data
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**
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** Freelist pages come in two subtypes: trunk pages and leaf pages. The
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** file header points to the first in a linked list of trunk page. Each trunk
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** page points to multiple leaf pages. The content of a leaf page is
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** unspecified. A trunk page looks like this:
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**
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** SIZE DESCRIPTION
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** 4 Page number of next trunk page
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** 4 Number of leaf pointers on this page
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** * zero or more pages numbers of leaves
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*/
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#include "sqliteInt.h"
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#include "pager.h"
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#include "btree.h"
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#include "os.h"
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#include <assert.h>
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/* Round up a number to the next larger multiple of 8. This is used
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** to force 8-byte alignment on 64-bit architectures.
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*/
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#define ROUND8(x) ((x+7)&~7)
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/* The following value is the maximum cell size assuming a maximum page
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** size give above.
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*/
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#define MX_CELL_SIZE(pBt) (pBt->pageSize-8)
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/* The maximum number of cells on a single page of the database. This
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** assumes a minimum cell size of 3 bytes. Such small cells will be
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** exceedingly rare, but they are possible.
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*/
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#define MX_CELL(pBt) ((pBt->pageSize-8)/3)
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/* Forward declarations */
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typedef struct MemPage MemPage;
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typedef struct BtLock BtLock;
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/*
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** This is a magic string that appears at the beginning of every
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** SQLite database in order to identify the file as a real database.
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**
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** You can change this value at compile-time by specifying a
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** -DSQLITE_FILE_HEADER="..." on the compiler command-line. The
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** header must be exactly 16 bytes including the zero-terminator so
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** the string itself should be 15 characters long. If you change
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** the header, then your custom library will not be able to read
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** databases generated by the standard tools and the standard tools
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** will not be able to read databases created by your custom library.
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*/
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#ifndef SQLITE_FILE_HEADER /* 123456789 123456 */
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# define SQLITE_FILE_HEADER "SQLite format 3"
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#endif
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/*
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** Page type flags. An ORed combination of these flags appear as the
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** first byte of every BTree page.
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*/
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#define PTF_INTKEY 0x01
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#define PTF_ZERODATA 0x02
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#define PTF_LEAFDATA 0x04
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#define PTF_LEAF 0x08
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/*
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** As each page of the file is loaded into memory, an instance of the following
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** structure is appended and initialized to zero. This structure stores
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** information about the page that is decoded from the raw file page.
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**
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** The pParent field points back to the parent page. This allows us to
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** walk up the BTree from any leaf to the root. Care must be taken to
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** unref() the parent page pointer when this page is no longer referenced.
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** The pageDestructor() routine handles that chore.
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*/
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struct MemPage {
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u8 isInit; /* True if previously initialized. MUST BE FIRST! */
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u8 idxShift; /* True if Cell indices have changed */
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u8 nOverflow; /* Number of overflow cell bodies in aCell[] */
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u8 intKey; /* True if intkey flag is set */
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u8 leaf; /* True if leaf flag is set */
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u8 zeroData; /* True if table stores keys only */
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u8 leafData; /* True if tables stores data on leaves only */
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u8 hasData; /* True if this page stores data */
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u8 hdrOffset; /* 100 for page 1. 0 otherwise */
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u8 childPtrSize; /* 0 if leaf==1. 4 if leaf==0 */
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u16 maxLocal; /* Copy of Btree.maxLocal or Btree.maxLeaf */
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u16 minLocal; /* Copy of Btree.minLocal or Btree.minLeaf */
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u16 cellOffset; /* Index in aData of first cell pointer */
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u16 idxParent; /* Index in parent of this node */
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u16 nFree; /* Number of free bytes on the page */
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u16 nCell; /* Number of cells on this page, local and ovfl */
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struct _OvflCell { /* Cells that will not fit on aData[] */
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u8 *pCell; /* Pointers to the body of the overflow cell */
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u16 idx; /* Insert this cell before idx-th non-overflow cell */
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} aOvfl[5];
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BtShared *pBt; /* Pointer back to BTree structure */
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u8 *aData; /* Pointer back to the start of the page */
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DbPage *pDbPage; /* Pager page handle */
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Pgno pgno; /* Page number for this page */
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MemPage *pParent; /* The parent of this page. NULL for root */
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};
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/*
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** The in-memory image of a disk page has the auxiliary information appended
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** to the end. EXTRA_SIZE is the number of bytes of space needed to hold
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** that extra information.
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*/
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#define EXTRA_SIZE sizeof(MemPage)
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/* Btree handle */
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struct Btree {
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sqlite3 *pSqlite;
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BtShared *pBt;
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u8 inTrans; /* TRANS_NONE, TRANS_READ or TRANS_WRITE */
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};
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/*
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** Btree.inTrans may take one of the following values.
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**
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** If the shared-data extension is enabled, there may be multiple users
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** of the Btree structure. At most one of these may open a write transaction,
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** but any number may have active read transactions. Variable Btree.pDb
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** points to the handle that owns any current write-transaction.
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*/
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#define TRANS_NONE 0
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#define TRANS_READ 1
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#define TRANS_WRITE 2
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/*
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** Everything we need to know about an open database
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*/
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struct BtShared {
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Pager *pPager; /* The page cache */
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BtCursor *pCursor; /* A list of all open cursors */
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MemPage *pPage1; /* First page of the database */
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u8 inStmt; /* True if we are in a statement subtransaction */
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u8 readOnly; /* True if the underlying file is readonly */
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u8 maxEmbedFrac; /* Maximum payload as % of total page size */
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u8 minEmbedFrac; /* Minimum payload as % of total page size */
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u8 minLeafFrac; /* Minimum leaf payload as % of total page size */
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u8 pageSizeFixed; /* True if the page size can no longer be changed */
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#ifndef SQLITE_OMIT_AUTOVACUUM
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u8 autoVacuum; /* True if auto-vacuum is enabled */
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u8 incrVacuum; /* True if incr-vacuum is enabled */
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Pgno nTrunc; /* Non-zero if the db will be truncated (incr vacuum) */
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#endif
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u16 pageSize; /* Total number of bytes on a page */
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u16 usableSize; /* Number of usable bytes on each page */
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int maxLocal; /* Maximum local payload in non-LEAFDATA tables */
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int minLocal; /* Minimum local payload in non-LEAFDATA tables */
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int maxLeaf; /* Maximum local payload in a LEAFDATA table */
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int minLeaf; /* Minimum local payload in a LEAFDATA table */
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BusyHandler *pBusyHandler; /* Callback for when there is lock contention */
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u8 inTransaction; /* Transaction state */
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int nRef; /* Number of references to this structure */
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int nTransaction; /* Number of open transactions (read + write) */
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void *pSchema; /* Pointer to space allocated by sqlite3BtreeSchema() */
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void (*xFreeSchema)(void*); /* Destructor for BtShared.pSchema */
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#ifndef SQLITE_OMIT_SHARED_CACHE
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BtLock *pLock; /* List of locks held on this shared-btree struct */
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BtShared *pNext; /* Next in ThreadData.pBtree linked list */
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#endif
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};
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/*
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** An instance of the following structure is used to hold information
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** about a cell. The parseCellPtr() function fills in this structure
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** based on information extract from the raw disk page.
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*/
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typedef struct CellInfo CellInfo;
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struct CellInfo {
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u8 *pCell; /* Pointer to the start of cell content */
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i64 nKey; /* The key for INTKEY tables, or number of bytes in key */
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u32 nData; /* Number of bytes of data */
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u32 nPayload; /* Total amount of payload */
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u16 nHeader; /* Size of the cell content header in bytes */
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u16 nLocal; /* Amount of payload held locally */
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u16 iOverflow; /* Offset to overflow page number. Zero if no overflow */
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u16 nSize; /* Size of the cell content on the main b-tree page */
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};
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/*
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** A cursor is a pointer to a particular entry in the BTree.
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** The entry is identified by its MemPage and the index in
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** MemPage.aCell[] of the entry.
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*/
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struct BtCursor {
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Btree *pBtree; /* The Btree to which this cursor belongs */
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BtCursor *pNext, *pPrev; /* Forms a linked list of all cursors */
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int (*xCompare)(void*,int,const void*,int,const void*); /* Key comp func */
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void *pArg; /* First arg to xCompare() */
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Pgno pgnoRoot; /* The root page of this tree */
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MemPage *pPage; /* Page that contains the entry */
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int idx; /* Index of the entry in pPage->aCell[] */
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CellInfo info; /* A parse of the cell we are pointing at */
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u8 wrFlag; /* True if writable */
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u8 eState; /* One of the CURSOR_XXX constants (see below) */
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void *pKey; /* Saved key that was cursor's last known position */
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i64 nKey; /* Size of pKey, or last integer key */
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int skip; /* (skip<0) -> Prev() is a no-op. (skip>0) -> Next() is */
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#ifndef SQLITE_OMIT_INCRBLOB
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u8 isIncrblobHandle; /* True if this cursor is an incr. io handle */
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Pgno *aOverflow; /* Cache of overflow page locations */
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#endif
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};
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/*
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** Potential values for BtCursor.eState.
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**
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** CURSOR_VALID:
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** Cursor points to a valid entry. getPayload() etc. may be called.
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**
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** CURSOR_INVALID:
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** Cursor does not point to a valid entry. This can happen (for example)
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** because the table is empty or because BtreeCursorFirst() has not been
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** called.
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**
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** CURSOR_REQUIRESEEK:
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** The table that this cursor was opened on still exists, but has been
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** modified since the cursor was last used. The cursor position is saved
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** in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in
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** this state, restoreOrClearCursorPosition() can be called to attempt to
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** seek the cursor to the saved position.
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*/
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#define CURSOR_INVALID 0
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#define CURSOR_VALID 1
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#define CURSOR_REQUIRESEEK 2
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/*
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** The TRACE macro will print high-level status information about the
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** btree operation when the global variable sqlite3_btree_trace is
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** enabled.
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*/
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#if SQLITE_TEST
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# define TRACE(X) if( sqlite3_btree_trace ){ printf X; fflush(stdout); }
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#else
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# define TRACE(X)
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#endif
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/*
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** Routines to read and write variable-length integers. These used to
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** be defined locally, but now we use the varint routines in the util.c
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** file.
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*/
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#define getVarint sqlite3GetVarint
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#define getVarint32(A,B) ((*B=*(A))<=0x7f?1:sqlite3GetVarint32(A,B))
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#define putVarint sqlite3PutVarint
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/* The database page the PENDING_BYTE occupies. This page is never used.
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** TODO: This macro is very similary to PAGER_MJ_PGNO() in pager.c. They
|
|
** should possibly be consolidated (presumably in pager.h).
|
|
**
|
|
** If disk I/O is omitted (meaning that the database is stored purely
|
|
** in memory) then there is no pending byte.
|
|
*/
|
|
#ifdef SQLITE_OMIT_DISKIO
|
|
# define PENDING_BYTE_PAGE(pBt) 0x7fffffff
|
|
#else
|
|
# define PENDING_BYTE_PAGE(pBt) ((PENDING_BYTE/(pBt)->pageSize)+1)
|
|
#endif
|
|
|
|
/*
|
|
** A linked list of the following structures is stored at BtShared.pLock.
|
|
** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor
|
|
** is opened on the table with root page BtShared.iTable. Locks are removed
|
|
** from this list when a transaction is committed or rolled back, or when
|
|
** a btree handle is closed.
|
|
*/
|
|
struct BtLock {
|
|
Btree *pBtree; /* Btree handle holding this lock */
|
|
Pgno iTable; /* Root page of table */
|
|
u8 eLock; /* READ_LOCK or WRITE_LOCK */
|
|
BtLock *pNext; /* Next in BtShared.pLock list */
|
|
};
|
|
|
|
/* Candidate values for BtLock.eLock */
|
|
#define READ_LOCK 1
|
|
#define WRITE_LOCK 2
|
|
|
|
/*
|
|
** These macros define the location of the pointer-map entry for a
|
|
** database page. The first argument to each is the number of usable
|
|
** bytes on each page of the database (often 1024). The second is the
|
|
** page number to look up in the pointer map.
|
|
**
|
|
** PTRMAP_PAGENO returns the database page number of the pointer-map
|
|
** page that stores the required pointer. PTRMAP_PTROFFSET returns
|
|
** the offset of the requested map entry.
|
|
**
|
|
** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page,
|
|
** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be
|
|
** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements
|
|
** this test.
|
|
*/
|
|
#define PTRMAP_PAGENO(pBt, pgno) ptrmapPageno(pBt, pgno)
|
|
#define PTRMAP_PTROFFSET(pBt, pgno) (5*(pgno-ptrmapPageno(pBt, pgno)-1))
|
|
#define PTRMAP_ISPAGE(pBt, pgno) (PTRMAP_PAGENO((pBt),(pgno))==(pgno))
|
|
|
|
/*
|
|
** The pointer map is a lookup table that identifies the parent page for
|
|
** each child page in the database file. The parent page is the page that
|
|
** contains a pointer to the child. Every page in the database contains
|
|
** 0 or 1 parent pages. (In this context 'database page' refers
|
|
** to any page that is not part of the pointer map itself.) Each pointer map
|
|
** entry consists of a single byte 'type' and a 4 byte parent page number.
|
|
** The PTRMAP_XXX identifiers below are the valid types.
|
|
**
|
|
** The purpose of the pointer map is to facility moving pages from one
|
|
** position in the file to another as part of autovacuum. When a page
|
|
** is moved, the pointer in its parent must be updated to point to the
|
|
** new location. The pointer map is used to locate the parent page quickly.
|
|
**
|
|
** PTRMAP_ROOTPAGE: The database page is a root-page. The page-number is not
|
|
** used in this case.
|
|
**
|
|
** PTRMAP_FREEPAGE: The database page is an unused (free) page. The page-number
|
|
** is not used in this case.
|
|
**
|
|
** PTRMAP_OVERFLOW1: The database page is the first page in a list of
|
|
** overflow pages. The page number identifies the page that
|
|
** contains the cell with a pointer to this overflow page.
|
|
**
|
|
** PTRMAP_OVERFLOW2: The database page is the second or later page in a list of
|
|
** overflow pages. The page-number identifies the previous
|
|
** page in the overflow page list.
|
|
**
|
|
** PTRMAP_BTREE: The database page is a non-root btree page. The page number
|
|
** identifies the parent page in the btree.
|
|
*/
|
|
#define PTRMAP_ROOTPAGE 1
|
|
#define PTRMAP_FREEPAGE 2
|
|
#define PTRMAP_OVERFLOW1 3
|
|
#define PTRMAP_OVERFLOW2 4
|
|
#define PTRMAP_BTREE 5
|
|
|
|
/* A bunch of assert() statements to check the transaction state variables
|
|
** of handle p (type Btree*) are internally consistent.
|
|
*/
|
|
#define btreeIntegrity(p) \
|
|
assert( p->inTrans!=TRANS_NONE || p->pBt->nTransaction<p->pBt->nRef ); \
|
|
assert( p->pBt->nTransaction<=p->pBt->nRef ); \
|
|
assert( p->pBt->inTransaction!=TRANS_NONE || p->pBt->nTransaction==0 ); \
|
|
assert( p->pBt->inTransaction>=p->inTrans );
|
|
|
|
|
|
/*
|
|
** The ISAUTOVACUUM macro is used within balance_nonroot() to determine
|
|
** if the database supports auto-vacuum or not. Because it is used
|
|
** within an expression that is an argument to another macro
|
|
** (sqliteMallocRaw), it is not possible to use conditional compilation.
|
|
** So, this macro is defined instead.
|
|
*/
|
|
#ifndef SQLITE_OMIT_AUTOVACUUM
|
|
#define ISAUTOVACUUM (pBt->autoVacuum)
|
|
#else
|
|
#define ISAUTOVACUUM 0
|
|
#endif
|
|
|
|
|
|
/*
|
|
** This structure is passed around through all the sanity checking routines
|
|
** in order to keep track of some global state information.
|
|
*/
|
|
typedef struct IntegrityCk IntegrityCk;
|
|
struct IntegrityCk {
|
|
BtShared *pBt; /* The tree being checked out */
|
|
Pager *pPager; /* The associated pager. Also accessible by pBt->pPager */
|
|
int nPage; /* Number of pages in the database */
|
|
int *anRef; /* Number of times each page is referenced */
|
|
int mxErr; /* Stop accumulating errors when this reaches zero */
|
|
char *zErrMsg; /* An error message. NULL if no errors seen. */
|
|
int nErr; /* Number of messages written to zErrMsg so far */
|
|
};
|
|
|
|
/*
|
|
** Read or write a two- and four-byte big-endian integer values.
|
|
*/
|
|
#define get2byte(x) ((x)[0]<<8 | (x)[1])
|
|
#define put2byte(p,v) ((p)[0] = (v)>>8, (p)[1] = (v))
|
|
#define get4byte sqlite3Get4byte
|
|
#define put4byte sqlite3Put4byte
|
|
|
|
/*
|
|
** Internal routines that should be accessed by the btree layer only.
|
|
*/
|
|
int sqlite3BtreeGetPage(BtShared*, Pgno, MemPage**, int);
|
|
int sqlite3BtreeInitPage(MemPage *pPage, MemPage *pParent);
|
|
void sqlite3BtreeParseCellPtr(MemPage*, u8*, CellInfo*);
|
|
void sqlite3BtreeParseCell(MemPage*, int, CellInfo*);
|
|
u8 *sqlite3BtreeFindCell(MemPage *pPage, int iCell);
|
|
int sqlite3BtreeRestoreOrClearCursorPosition(BtCursor *pCur);
|
|
void sqlite3BtreeGetTempCursor(BtCursor *pCur, BtCursor *pTempCur);
|
|
void sqlite3BtreeReleaseTempCursor(BtCursor *pCur);
|
|
int sqlite3BtreeIsRootPage(MemPage *pPage);
|
|
void sqlite3BtreeMoveToParent(BtCursor *pCur);
|