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Diffstat (limited to 'src')
| -rw-r--r-- | src/wal.c | 64 |
1 files changed, 64 insertions, 0 deletions
@@ -400,6 +400,70 @@ struct WalCkptInfo { }; #define READMARK_NOT_USED 0xffffffff +/* +** This is a schematic view of the complete 136-byte header of the +** wal-index file (also known as the -shm file): +** +** +-----------------------------+ +** 0: | iVersion | \ +** +-----------------------------+ | +** 4: | (unused padding) | | +** +-----------------------------+ | +** 8: | iChange | | +** +-------+-------+-------------+ | +** 12: | bInit | bBig | szPage | | +** +-------+-------+-------------+ | +** 16: | mxFrame | | First copy of the +** +-----------------------------+ | WalIndexHdr object +** 20: | nPage | | +** +-----------------------------+ | +** 24: | aFrameCksum | | +** | | | +** +-----------------------------+ | +** 32: | aSalt | | +** | | | +** +-----------------------------+ | +** 40: | aCksum | | +** | | / +** +-----------------------------+ +** 48: | iVersion | \ +** +-----------------------------+ | +** 52: | (unused padding) | | +** +-----------------------------+ | +** 56: | iChange | | +** +-------+-------+-------------+ | +** 60: | bInit | bBig | szPage | | +** +-------+-------+-------------+ | Second copy of the +** 64: | mxFrame | | WalIndexHdr +** +-----------------------------+ | +** 68: | nPage | | +** +-----------------------------+ | +** 72: | aFrameCksum | | +** | | | +** +-----------------------------+ | +** 80: | aSalt | | +** | | | +** +-----------------------------+ | +** 88: | aCksum | | +** | | / +** +-----------------------------+ +** 96: | nBackfill | +** +-----------------------------+ +** 100: | 5 read marks | +** | | +** | | +** | | +** | | +** +-------+-------+------+------+ +** 120: | Write | Ckpt | Rcvr | Rd0 | \ +** +-------+-------+------+------+ ) 8 lock bytes +** | Read1 | Read2 | Rd3 | Rd4 | / +** +-------+-------+------+------+ +** 128: | nBackfillAttempted | +** +-----------------------------+ +** 132: | (unused padding) | +** +-----------------------------+ +*/ /* A block of WALINDEX_LOCK_RESERVED bytes beginning at ** WALINDEX_LOCK_OFFSET is reserved for locks. Since some systems |