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Changes In Branch sorter-limit-opt Excluding Merge-Ins
This is equivalent to a diff from 7bb23c2a to 71bf91c2
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2018-04-26
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| 17:43 | When processing an "ORDER BY ... LIMIT" that does not use an index, check whether or not a record may appear in the final result set before adding it to the temp b-tree used for sorting. (check-in: 0fcfc36c user: dan tags: trunk) | |
| 16:13 | When processing an "ORDER BY ... LIMIT" that does not use an index, check whether or not a record may appear in the final result set before adding it to the sorter. (Closed-Leaf check-in: 71bf91c2 user: dan tags: sorter-limit-opt) | |
| 15:50 | Ensure that new.* values of an UPDATE do not get clobbered after the BEFORE triggers run when unmodified columns of the row being updated are reloaded. Fix for ticket [d85fffd6ffe856092ed8da] (check-in: 0a514e62 user: drh tags: trunk) | |
| 15:04 | Clarification of the behavior of a BEFORE UPDATE trigger when the trigger changes the values of some of the columns used to compute new columns in the UPDATE. (check-in: 7bb23c2a user: drh tags: trunk) | |
| 12:27 | Improved VDBE comment on the OP_Param opcode. No substantial changes. (check-in: 368c14da user: drh tags: trunk) | |
Changes to src/select.c.
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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);
}
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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);
}
if( nOBSat>0 ){
int regPrevKey; /* The first nOBSat columns of the previous row */
int addrFirst; /* Address of the OP_IfNot opcode */
int addrJmp; /* Address of the OP_Jump opcode */
VdbeOp *pOp; /* Opcode that opens the sorter */
int nKey; /* Number of sorting key columns, including OP_Sequence */
KeyInfo *pKI; /* Original KeyInfo on the sorter table */
sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nBase-nOBSat,regRecord);
regPrevKey = pParse->nMem+1;
pParse->nMem += pSort->nOBSat;
nKey = nExpr - pSort->nOBSat + bSeq;
if( bSeq ){
addrFirst = sqlite3VdbeAddOp1(v, OP_IfNot, regBase+nExpr);
}else{
addrFirst = sqlite3VdbeAddOp1(v, OP_SequenceTest, pSort->iECursor);
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sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, pSort->labelDone);
VdbeCoverage(v);
}
sqlite3VdbeJumpHere(v, addrFirst);
sqlite3ExprCodeMove(pParse, regBase, regPrevKey, pSort->nOBSat);
sqlite3VdbeJumpHere(v, addrJmp);
}
if( pSort->sortFlags & SORTFLAG_UseSorter ){
op = OP_SorterInsert;
}else{
op = OP_IdxInsert;
}
sqlite3VdbeAddOp4Int(v, op, pSort->iECursor, regRecord,
regBase+nOBSat, nBase-nOBSat);
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sqlite3VdbeAddOp2(v, OP_IfNot, iLimit, pSort->labelDone);
VdbeCoverage(v);
}
sqlite3VdbeJumpHere(v, addrFirst);
sqlite3ExprCodeMove(pParse, regBase, regPrevKey, pSort->nOBSat);
sqlite3VdbeJumpHere(v, addrJmp);
}
if( iLimit ){
/* At this point the values for the new sorter entry are stored
** in an array of registers. They need to be composed into a record
** and inserted into the sorter if either (a) there are currently
** less than LIMIT+OFFSET items or (b) the new record is smaller than
** the largest record currently in the sorter. If (b) is true and there
** are already LIMIT+OFFSET items in the sorter, delete the largest
** entry before inserting the new one. This way there are never more
** than LIMIT+OFFSET items in the sorter.
**
** If the new record does not need to be inserted into the sorter,
** jump to the next iteration of the loop. Or, if the
** pSort->bOrderedInnerLoop flag is set to indicate that the inner
** loop delivers items in sorted order, jump to the next iteration
** of the outer loop.
*/
int iCsr = pSort->iECursor;
int iJmp = sqlite3VdbeCurrentAddr(v)+5+(nOBSat<=0)+pSort->bOrderedInnerLoop;
assert( pSort->bOrderedInnerLoop==0 || pSort->bOrderedInnerLoop==1 );
sqlite3VdbeAddOp2(v, OP_IfNotZero, iLimit, sqlite3VdbeCurrentAddr(v)+4);
VdbeCoverage(v);
sqlite3VdbeAddOp2(v, OP_Last, iCsr, 0);
sqlite3VdbeAddOp4Int(v, OP_IdxLE, iCsr, iJmp, regBase+nOBSat, nExpr-nOBSat);
VdbeCoverage(v);
sqlite3VdbeAddOp1(v, OP_Delete, iCsr);
}
if( nOBSat<=0 ){
sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase+nOBSat, nBase-nOBSat,regRecord);
}
if( pSort->sortFlags & SORTFLAG_UseSorter ){
op = OP_SorterInsert;
}else{
op = OP_IdxInsert;
}
sqlite3VdbeAddOp4Int(v, op, pSort->iECursor, regRecord,
regBase+nOBSat, nBase-nOBSat);
}
/*
** Add code to implement the OFFSET
*/
static void codeOffset(
Vdbe *v, /* Generate code into this VM */
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