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Overview
| Comment: | Performance optimization for the OP_Column opcode. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
076be5474df628bbbfd2b645adba30e1 |
| User & Date: | drh 2015-10-15 21:30:24.579 |
Context
|
2015-10-16
| ||
| 12:39 | Improved header comment on the tool/vdbe_profile.tcl script. No changes to code. (check-in: b17ad8fc04 user: drh tags: trunk) | |
| 03:34 | Whenever two or more OP_Column opcodes on the same cursor occur in succession, try to reordering them so that the one that extracts the right-most column is first, so that it will warm up the row cache for all those that follow. This gives a small performance boost. (Leaf check-in: 08e8f04d12 user: drh tags: reorder-column-opcodes) | |
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2015-10-15
| ||
| 21:30 | Performance optimization for the OP_Column opcode. (check-in: 076be5474d user: drh tags: trunk) | |
| 19:21 | Enhance the use of the column cache for UPDATE statements, making them more efficient for the case where a column is modified to be an expression of other unmodified columns. (check-in: 871e091df6 user: drh tags: trunk) | |
Changes
Changes to src/vdbe.c.
| ︙ | ︙ | |||
2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 | int i; /* Loop counter */ Mem *pDest; /* Where to write the extracted value */ Mem sMem; /* For storing the record being decoded */ const u8 *zData; /* Part of the record being decoded */ const u8 *zHdr; /* Next unparsed byte of the header */ const u8 *zEndHdr; /* Pointer to first byte after the header */ u32 offset; /* Offset into the data */ u32 szField; /* Number of bytes in the content of a field */ u32 avail; /* Number of bytes of available data */ u32 t; /* A type code from the record header */ u16 fx; /* pDest->flags value */ Mem *pReg; /* PseudoTable input register */ p2 = pOp->p2; | > | 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 | int i; /* Loop counter */ Mem *pDest; /* Where to write the extracted value */ Mem sMem; /* For storing the record being decoded */ const u8 *zData; /* Part of the record being decoded */ const u8 *zHdr; /* Next unparsed byte of the header */ const u8 *zEndHdr; /* Pointer to first byte after the header */ u32 offset; /* Offset into the data */ u64 offset64; /* 64-bit offset */ u32 szField; /* Number of bytes in the content of a field */ u32 avail; /* Number of bytes of available data */ u32 t; /* A type code from the record header */ u16 fx; /* pDest->flags value */ Mem *pReg; /* PseudoTable input register */ p2 = pOp->p2; |
| ︙ | ︙ | |||
2490 2491 2492 2493 2494 2495 2496 |
zData = (u8*)sMem.z;
}else{
zData = pC->aRow;
}
/* Fill in pC->aType[i] and aOffset[i] values through the p2-th field. */
i = pC->nHdrParsed;
| | | < < < < | | | | | | 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 |
zData = (u8*)sMem.z;
}else{
zData = pC->aRow;
}
/* Fill in pC->aType[i] and aOffset[i] values through the p2-th field. */
i = pC->nHdrParsed;
offset64 = aOffset[i];
zHdr = zData + pC->iHdrOffset;
zEndHdr = zData + aOffset[0];
assert( i<=p2 && zHdr<zEndHdr );
do{
if( zHdr[0]<0x80 ){
t = zHdr[0];
zHdr++;
}else{
zHdr += sqlite3GetVarint32(zHdr, &t);
}
pC->aType[i] = t;
szField = sqlite3VdbeSerialTypeLen(t);
offset64 += szField;
i++;
aOffset[i] = (u32)(offset64 & 0xffffffff);
}while( i<=p2 && zHdr<zEndHdr );
pC->nHdrParsed = i;
pC->iHdrOffset = (u32)(zHdr - zData);
if( pC->aRow==0 ){
sqlite3VdbeMemRelease(&sMem);
sMem.flags = MEM_Null;
}
/* The record is corrupt if any of the following are true:
** (1) the bytes of the header extend past the declared header size
** (zHdr>zEndHdr)
** (2) the entire header was used but not all data was used
** (zHdr==zEndHdr && offset64!=pC->payloadSize)
** (3) the end of the data extends beyond the end of the record.
** (offset64 > pC->payloadSize)
*/
if( (zHdr>=zEndHdr && (zHdr>zEndHdr || offset64!=pC->payloadSize))
|| (offset64 > pC->payloadSize)
){
rc = SQLITE_CORRUPT_BKPT;
goto op_column_error;
}
}
/* If after trying to extract new entries from the header, nHdrParsed is
|
| ︙ | ︙ |