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").
FossilOrigin-Name: 0af62fdbd8e2aab14718ff8bcb5934f05463c176
diff --git a/src/expr.c b/src/expr.c
index c2b9c8f..165bb30 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4086,8 +4086,13 @@
if( !ConstFactorOk(pParse) ) flags &= ~SQLITE_ECEL_FACTOR;
for(pItem=pList->a, i=0; i<n; i++, pItem++){
Expr *pExpr = pItem->pExpr;
- if( (flags & SQLITE_ECEL_REF)!=0 && (j = pList->a[i].u.x.iOrderByCol)>0 ){
- sqlite3VdbeAddOp2(v, copyOp, j+srcReg-1, target+i);
+ if( (flags & SQLITE_ECEL_REF)!=0 && (j = pItem->u.x.iOrderByCol)>0 ){
+ if( flags & SQLITE_ECEL_OMITREF ){
+ i--;
+ n--;
+ }else{
+ sqlite3VdbeAddOp2(v, copyOp, j+srcReg-1, target+i);
+ }
}else if( (flags & SQLITE_ECEL_FACTOR)!=0 && sqlite3ExprIsConstant(pExpr) ){
sqlite3ExprCodeAtInit(pParse, pExpr, target+i, 0);
}else{
diff --git a/src/select.c b/src/select.c
index 199e13f..003d42e 100644
--- a/src/select.c
+++ b/src/select.c
@@ -533,11 +533,11 @@
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);
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);
@@ -666,7 +666,7 @@
** 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 */
@@ -734,7 +734,25 @@
}else{
ecelFlags = 0;
}
- sqlite3ExprCodeExprList(pParse, pEList, regResult, 0, ecelFlags);
+ if( pSort && hasDistinct==0 && eDest!=SRT_EphemTab && eDest!=SRT_Table ){
+ /* 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;
+ }
+ }
+
+ 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
@@ -900,11 +918,12 @@
** 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);
}else{
+ assert( nResultCol==pDest->nSdst );
assert( regResult==iParm );
/* The LIMIT clause will jump out of the loop for us */
}
@@ -1202,14 +1221,13 @@
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 ){
@@ -1247,8 +1265,14 @@
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 ){
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index c0e5aa0..8866295 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3706,6 +3706,7 @@
#define SQLITE_ECEL_DUP 0x01 /* Deep, not shallow copies */
#define SQLITE_ECEL_FACTOR 0x02 /* Factor out constant terms */
#define SQLITE_ECEL_REF 0x04 /* Use ExprList.u.x.iOrderByCol */
+#define SQLITE_ECEL_OMITREF 0x08 /* Omit if ExprList.u.x.iOrderByCol */
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
void sqlite3ExprIfFalseDup(Parse*, Expr*, int, int);