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Overview
Comment: | Simplify the OP_Column logic slightly. One very small performance improvement added. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
0114b45dc286c13db0d640f0486d8a5b |
User & Date: | drh 2015-10-16 13:50:08.508 |
Context
2015-10-16
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14:23 | Use a lookup table to compute the content length for serial types less than 128, for a 1.2% performance improvement. (check-in: 3395724814 user: drh tags: trunk) | |
13:50 | Simplify the OP_Column logic slightly. One very small performance improvement added. (check-in: 0114b45dc2 user: drh tags: trunk) | |
12:53 | OP_Column optimization: Do not check for an oversize row header unless the row header size is larger than the content available on the local page. (check-in: 8125b74cb4 user: drh tags: trunk) | |
Changes
Changes to src/vdbe.c.
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2480 2481 2482 2483 2484 2485 2486 | ** to extract additional fields up through the p2+1-th field */ op_column_read_header: if( pC->iHdrOffset<aOffset[0] ){ /* Make sure zData points to enough of the record to cover the header. */ if( pC->aRow==0 ){ memset(&sMem, 0, sizeof(sMem)); | | < | < < < | | < < < < < < | 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 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 | ** to extract additional fields up through the p2+1-th field */ op_column_read_header: if( pC->iHdrOffset<aOffset[0] ){ /* Make sure zData points to enough of the record to cover the header. */ if( pC->aRow==0 ){ memset(&sMem, 0, sizeof(sMem)); rc = sqlite3VdbeMemFromBtree(pCrsr, 0, aOffset[0], !pC->isTable, &sMem); if( rc!=SQLITE_OK ) goto op_column_error; 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( (t = zHdr[0])<0x80 ){ 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); /* The record is corrupt if any of the following are true: ** (1) the bytes of the header extend past the declared header size ** (2) the entire header was used but not all data was used ** (3) the end of the data extends beyond the end of the record. */ if( (zHdr>=zEndHdr && (zHdr>zEndHdr || offset64!=pC->payloadSize)) || (offset64 > pC->payloadSize) ){ rc = SQLITE_CORRUPT_BKPT; goto op_column_error; } |
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2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 | if( pOp->p4type==P4_MEM ){ sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static); }else{ sqlite3VdbeMemSetNull(pDest); } goto op_column_out; } } /* Extract the content for the p2+1-th column. Control can only ** reach this point if aOffset[p2], aOffset[p2+1], and pC->aType[p2] are ** all valid. */ assert( p2<pC->nHdrParsed ); assert( rc==SQLITE_OK ); assert( sqlite3VdbeCheckMemInvariants(pDest) ); if( VdbeMemDynamic(pDest) ) sqlite3VdbeMemSetNull(pDest); | > > | | 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 | if( pOp->p4type==P4_MEM ){ sqlite3VdbeMemShallowCopy(pDest, pOp->p4.pMem, MEM_Static); }else{ sqlite3VdbeMemSetNull(pDest); } goto op_column_out; } }else{ t = pC->aType[p2]; } /* Extract the content for the p2+1-th column. Control can only ** reach this point if aOffset[p2], aOffset[p2+1], and pC->aType[p2] are ** all valid. */ assert( p2<pC->nHdrParsed ); assert( rc==SQLITE_OK ); assert( sqlite3VdbeCheckMemInvariants(pDest) ); if( VdbeMemDynamic(pDest) ) sqlite3VdbeMemSetNull(pDest); assert( t==pC->aType[p2] ); if( pC->szRow>=aOffset[p2+1] ){ /* This is the common case where the desired content fits on the original ** page - where the content is not on an overflow page */ sqlite3VdbeSerialGet(pC->aRow+aOffset[p2], t, pDest); }else{ /* This branch happens only when content is on overflow pages */ if( ((pOp->p5 & (OPFLAG_LENGTHARG|OPFLAG_TYPEOFARG))!=0 |
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