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Overview
Comment: | Reenable the SQLITE_EXPR_REF optimization for "SELECT DISTINCT ... ORDER BY" queries. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | sorter-opt |
Files: | files | file ages | folders |
SHA1: |
6e2e9d383f5fc4a0cbf05fe83ec74258 |
User & Date: | dan 2016-11-11 18:08:59.063 |
Context
2016-11-11
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18:45 | Merge trunk with this branch. (Closed-Leaf check-in: dd62d2de6e user: dan tags: sorter-opt) | |
18:08 | Reenable the SQLITE_EXPR_REF optimization for "SELECT DISTINCT ... ORDER BY" queries. (check-in: 6e2e9d383f user: dan tags: sorter-opt) | |
2016-11-10
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20:14 | Avoid storing redundant fields in sorter records when the sort-key and data have fields in common (as in "SELECT a FROM t1 ORDER BY 1"). (check-in: 0af62fdbd8 user: dan tags: sorter-opt) | |
Changes
Changes to src/select.c.
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517 518 519 520 521 522 523 | int regBase; /* Regs for sorter record */ int regRecord = ++pParse->nMem; /* Assembled sorter record */ int nOBSat = pSort->nOBSat; /* ORDER BY terms to skip */ int op; /* Opcode to add sorter record to sorter */ int iLimit; /* LIMIT counter */ assert( bSeq==0 || bSeq==1 ); | | | | 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 | int regBase; /* Regs for sorter record */ int regRecord = ++pParse->nMem; /* Assembled sorter record */ int nOBSat = pSort->nOBSat; /* ORDER BY terms to skip */ int op; /* Opcode to add sorter record to sorter */ int iLimit; /* LIMIT counter */ assert( bSeq==0 || bSeq==1 ); assert( nData==1 || regData==regOrigData || regOrigData==0 ); if( nPrefixReg ){ assert( nPrefixReg==nExpr+bSeq ); regBase = regData - nExpr - bSeq; }else{ regBase = pParse->nMem + 1; pParse->nMem += nBase; } assert( pSelect->iOffset==0 || pSelect->iLimit!=0 ); iLimit = pSelect->iOffset ? pSelect->iOffset+1 : pSelect->iLimit; pSort->labelDone = sqlite3VdbeMakeLabel(v); sqlite3ExprCodeExprList(pParse, pSort->pOrderBy, regBase, regOrigData, SQLITE_ECEL_DUP | (regOrigData? SQLITE_ECEL_REF : 0)); if( bSeq ){ sqlite3VdbeAddOp2(v, OP_Sequence, pSort->iECursor, regBase+nExpr); } if( nPrefixReg==0 && nData>0 ){ sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+bSeq, nData); } sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nBase-nOBSat, regRecord); |
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677 678 679 680 681 682 683 | DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */ SelectDest *pDest, /* How to dispose of the results */ int iContinue, /* Jump here to continue with next row */ int iBreak /* Jump here to break out of the inner loop */ ){ Vdbe *v = pParse->pVdbe; int i; | | < > > > > > > > > | 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 | DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */ SelectDest *pDest, /* How to dispose of the results */ int iContinue, /* Jump here to continue with next row */ int iBreak /* Jump here to break out of the inner loop */ ){ Vdbe *v = pParse->pVdbe; int i; int hasDistinct; /* True if the DISTINCT keyword is present */ int eDest = pDest->eDest; /* How to dispose of results */ int iParm = pDest->iSDParm; /* First argument to disposal method */ int nResultCol; /* Number of result columns */ int nPrefixReg = 0; /* Number of extra registers before regResult */ /* Usually, regResult is the first cell in an array of memory cells ** containing the current result row. In this case regOrig is set to the ** same value. However, if the results are being sent to the sorter, the ** values for any expressions that are also part of the sort-key are omitted ** from this array. In this case regOrig is set to zero. */ int regResult; /* Start of memory holding current results */ int regOrig; /* Start of memory holding full result (or 0) */ assert( v ); assert( pEList!=0 ); hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP; if( pSort && pSort->pOrderBy==0 ) pSort = 0; if( pSort==0 && !hasDistinct ){ assert( iContinue!=0 ); codeOffset(v, p->iOffset, iContinue); |
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714 715 716 717 718 719 720 | ** on the right-hand side of an INSERT contains more result columns than ** there are columns in the table on the left. The error will be caught ** and reported later. But we need to make sure enough memory is allocated ** to avoid other spurious errors in the meantime. */ pParse->nMem += nResultCol; } pDest->nSdst = nResultCol; | | > | | | 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 | ** on the right-hand side of an INSERT contains more result columns than ** there are columns in the table on the left. The error will be caught ** and reported later. But we need to make sure enough memory is allocated ** to avoid other spurious errors in the meantime. */ pParse->nMem += nResultCol; } pDest->nSdst = nResultCol; regOrig = regResult = pDest->iSdst; if( srcTab>=0 ){ for(i=0; i<nResultCol; i++){ sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i); VdbeComment((v, "%s", pEList->a[i].zName)); } }else if( eDest!=SRT_Exists ){ /* If the destination is an EXISTS(...) expression, the actual ** values returned by the SELECT are not required. */ u8 ecelFlags; if( eDest==SRT_Mem || eDest==SRT_Output || eDest==SRT_Coroutine ){ ecelFlags = SQLITE_ECEL_DUP; }else{ ecelFlags = 0; } assert( eDest!=SRT_Table || pSort==0 ); if( pSort && hasDistinct==0 && eDest!=SRT_EphemTab ){ /* For each expression in pEList that is a copy of an expression in ** the ORDER BY clause (pSort->pOrderBy), set the associated ** iOrderByCol value to one more than the index of the ORDER BY ** expression within the sort-key that pushOntoSorter() will generate. ** This allows the pEList field to be omitted from the sorted record, ** saving space and CPU cycles. */ ecelFlags |= (SQLITE_ECEL_OMITREF|SQLITE_ECEL_REF); for(i=pSort->nOBSat; i<pSort->pOrderBy->nExpr; i++){ int j; if( (j = pSort->pOrderBy->a[i].u.x.iOrderByCol)>0 ){ pEList->a[j-1].u.x.iOrderByCol = i+1-pSort->nOBSat; } } regOrig = 0; assert( eDest==SRT_Set || eDest==SRT_Mem || eDest==SRT_Coroutine || eDest==SRT_Output ); } nResultCol = sqlite3ExprCodeExprList(pParse,pEList,regResult,0,ecelFlags); } /* If the DISTINCT keyword was present on the SELECT statement |
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888 889 890 891 892 893 894 | case SRT_Set: { if( pSort ){ /* At first glance you would think we could optimize out the ** ORDER BY in this case since the order of entries in the set ** does not matter. But there might be a LIMIT clause, in which ** case the order does matter */ pushOntoSorter( | | | 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 | case SRT_Set: { if( pSort ){ /* At first glance you would think we could optimize out the ** ORDER BY in this case since the order of entries in the set ** does not matter. But there might be a LIMIT clause, in which ** case the order does matter */ pushOntoSorter( pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); }else{ int r1 = sqlite3GetTempReg(pParse); assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol ); sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, nResultCol, r1, pDest->zAffSdst, nResultCol); sqlite3ExprCacheAffinityChange(pParse, regResult, nResultCol); sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1); |
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917 918 919 920 921 922 923 | ** store the results in the appropriate memory cell or array of ** memory cells and break out of the scan loop. */ case SRT_Mem: { if( pSort ){ assert( nResultCol<=pDest->nSdst ); pushOntoSorter( | | | | 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 | ** store the results in the appropriate memory cell or array of ** memory cells and break out of the scan loop. */ case SRT_Mem: { if( pSort ){ assert( nResultCol<=pDest->nSdst ); pushOntoSorter( pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); }else{ assert( nResultCol==pDest->nSdst ); assert( regResult==iParm ); /* The LIMIT clause will jump out of the loop for us */ } break; } #endif /* #ifndef SQLITE_OMIT_SUBQUERY */ case SRT_Coroutine: /* Send data to a co-routine */ case SRT_Output: { /* Return the results */ testcase( eDest==SRT_Coroutine ); testcase( eDest==SRT_Output ); if( pSort ){ pushOntoSorter(pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); }else if( eDest==SRT_Coroutine ){ sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm); }else{ sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol); sqlite3ExprCacheAffinityChange(pParse, regResult, nResultCol); } |
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