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Performance improvements:

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Avoid unnecessary seeks when doing a single-row UPDATE on a WITHOUT ROWID
table.

FossilOrigin-Name: 6f187a0fb1b09ebc4732c4afbf3c813f82e069f1
This commit is contained in:
drh
2013-11-08 15:19:46 +00:00
parent 81897bb14e
commit fc8d4f96b4
6 changed files with 91 additions and 33 deletions
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30
src/update.c
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@@ -129,6 +129,7 @@ void sqlite3Update(
int newmask; /* Mask of NEW.* columns accessed by BEFORE triggers */
int iEph = 0; /* Ephemeral table holding all primary key values */
int nKey = 0; /* Number of elements in regKey for WITHOUT ROWID */
int aiCurOnePass[2]; /* The write cursors opened by WHERE_ONEPASS */
/* Register Allocations */
int regRowCount = 0; /* A count of rows changed */
@@ -336,10 +337,10 @@ void sqlite3Update(
if( HasRowid(pTab) ){
sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
pWInfo = sqlite3WhereBegin(
pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED, 0
pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED, iIdxCur
);
if( pWInfo==0 ) goto update_cleanup;
okOnePass = sqlite3WhereOkOnePass(pWInfo);
okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
/* Remember the rowid of every item to be updated.
*/
@@ -366,9 +367,9 @@ void sqlite3Update(
addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
sqlite3VdbeSetP4KeyInfo(pParse, pPk);
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0,
WHERE_ONEPASS_DESIRED, 0);
WHERE_ONEPASS_DESIRED, iIdxCur);
if( pWInfo==0 ) goto update_cleanup;
okOnePass = sqlite3WhereOkOnePass(pWInfo);
okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
for(i=0; i<nPk; i++){
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, pPk->aiColumn[i],
iPk+i);
@@ -392,6 +393,7 @@ void sqlite3Update(
sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
}
labelBreak = sqlite3VdbeMakeLabel(v);
if( !isView ){
/*
** Open every index that needs updating. Note that if any
@@ -415,24 +417,28 @@ void sqlite3Update(
}
}
for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
int iThisCur = iIdxCur+i;
assert( aRegIdx );
if( openAll || aRegIdx[i]>0 ){
sqlite3VdbeAddOp3(v, OP_OpenWrite, iIdxCur+i, pIdx->tnum, iDb);
if( (openAll || aRegIdx[i]>0)
&& iThisCur!=aiCurOnePass[0]
&& iThisCur!=aiCurOnePass[1]
){
sqlite3VdbeAddOp3(v, OP_OpenWrite, iThisCur, pIdx->tnum, iDb);
sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
assert( pParse->nTab>iIdxCur+i );
assert( pParse->nTab>iThisCur );
VdbeComment((v, "%s", pIdx->zName));
if( okOnePass && pPk && iThisCur==iDataCur ){
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak,
regKey, nKey);
}
}
}
}
/* Top of the update loop */
labelBreak = sqlite3VdbeMakeLabel(v);
if( okOnePass ){
labelContinue = labelBreak;
sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
if( pPk ){
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey, nKey);
}
}else if( pPk ){
labelContinue = sqlite3VdbeMakeLabel(v);
sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak);
@@ -624,7 +630,7 @@ void sqlite3Update(
for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
assert( aRegIdx );
if( openAll || aRegIdx[i]>0 ){
sqlite3VdbeAddOp2(v, OP_Close, iIdxCur, 0);
sqlite3VdbeAddOp2(v, OP_Close, iIdxCur+i, 0);
}
}
if( iDataCur<iIdxCur ) sqlite3VdbeAddOp2(v, OP_Close, iDataCur, 0);