diff options
Diffstat (limited to 'src/select.c')
| -rw-r--r-- | src/select.c | 64 |
1 files changed, 48 insertions, 16 deletions
diff --git a/src/select.c b/src/select.c index b82e7905c..ab3371e86 100644 --- a/src/select.c +++ b/src/select.c @@ -521,7 +521,7 @@ static void pushOntoSorter( int iLimit; /* LIMIT counter */ assert( bSeq==0 || bSeq==1 ); - assert( nData==1 || regData==regOrigData ); + assert( nData==1 || regData==regOrigData || regOrigData==0 ); if( nPrefixReg ){ assert( nPrefixReg==nExpr+bSeq ); regBase = regData - nExpr - bSeq; @@ -533,11 +533,11 @@ static void pushOntoSorter( iLimit = pSelect->iOffset ? pSelect->iOffset+1 : pSelect->iLimit; pSort->labelDone = sqlite3VdbeMakeLabel(v); sqlite3ExprCodeExprList(pParse, pSort->pOrderBy, regBase, regOrigData, - SQLITE_ECEL_DUP|SQLITE_ECEL_REF); + SQLITE_ECEL_DUP | (regOrigData? SQLITE_ECEL_REF : 0)); if( bSeq ){ sqlite3VdbeAddOp2(v, OP_Sequence, pSort->iECursor, regBase+nExpr); } - if( nPrefixReg==0 ){ + if( nPrefixReg==0 && nData>0 ){ sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+bSeq, nData); } sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nBase-nOBSat, regRecord); @@ -667,7 +667,7 @@ static void codeDistinct( ** If srcTab is negative, then the pEList expressions ** are evaluated in order to get the data for this row. If srcTab is ** zero or more, then data is pulled from srcTab and pEList is used only -** to get number columns and the datatype for each column. +** to get the number of columns and the collation sequence for each column. */ static void selectInnerLoop( Parse *pParse, /* The parser context */ @@ -682,13 +682,20 @@ static void selectInnerLoop( ){ Vdbe *v = pParse->pVdbe; int i; - int hasDistinct; /* True if the DISTINCT keyword is present */ - int regResult; /* Start of memory holding result set */ + 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; @@ -719,7 +726,7 @@ static void selectInnerLoop( pParse->nMem += nResultCol; } pDest->nSdst = nResultCol; - regResult = pDest->iSdst; + regOrig = regResult = pDest->iSdst; if( srcTab>=0 ){ for(i=0; i<nResultCol; i++){ sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i); @@ -735,7 +742,26 @@ static void selectInnerLoop( }else{ ecelFlags = 0; } - sqlite3ExprCodeExprList(pParse, pEList, regResult, 0, ecelFlags); + 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 @@ -875,7 +901,7 @@ static void selectInnerLoop( ** does not matter. But there might be a LIMIT clause, in which ** case the order does matter */ pushOntoSorter( - pParse, pSort, p, regResult, regResult, nResultCol, nPrefixReg); + pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); }else{ int r1 = sqlite3GetTempReg(pParse); assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol ); @@ -901,11 +927,12 @@ static void selectInnerLoop( ** memory cells and break out of the scan loop. */ case SRT_Mem: { - assert( nResultCol==pDest->nSdst ); if( pSort ){ + assert( nResultCol<=pDest->nSdst ); pushOntoSorter( - pParse, pSort, p, regResult, regResult, nResultCol, nPrefixReg); + 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 */ } @@ -918,7 +945,7 @@ static void selectInnerLoop( testcase( eDest==SRT_Coroutine ); testcase( eDest==SRT_Output ); if( pSort ){ - pushOntoSorter(pParse, pSort, p, regResult, regResult, nResultCol, + pushOntoSorter(pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg); }else if( eDest==SRT_Coroutine ){ sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm); @@ -1203,14 +1230,13 @@ static void generateSortTail( int iParm = pDest->iSDParm; int regRow; int regRowid; + int iCol; int nKey; int iSortTab; /* Sorter cursor to read from */ int nSortData; /* Trailing values to read from sorter */ int i; int bSeq; /* True if sorter record includes seq. no. */ -#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS struct ExprList_item *aOutEx = p->pEList->a; -#endif assert( addrBreak<0 ); if( pSort->labelBkOut ){ @@ -1248,8 +1274,14 @@ static void generateSortTail( iSortTab = iTab; bSeq = 1; } - for(i=0; i<nSortData; i++){ - sqlite3VdbeAddOp3(v, OP_Column, iSortTab, nKey+bSeq+i, regRow+i); + for(i=0, iCol=nKey+bSeq; i<nSortData; i++){ + int iRead; + if( aOutEx[i].u.x.iOrderByCol ){ + iRead = aOutEx[i].u.x.iOrderByCol-1; + }else{ + iRead = iCol++; + } + sqlite3VdbeAddOp3(v, OP_Column, iSortTab, iRead, regRow+i); VdbeComment((v, "%s", aOutEx[i].zName ? aOutEx[i].zName : aOutEx[i].zSpan)); } switch( eDest ){ |