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Enhance the automatic index logic so that it creates a partial index when

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doing so gives the same answer for less work.

FossilOrigin-Name: d95d0313c447f5baeabdb17284d8606331ab7d49
This commit is contained in:
drh
2014-10-24 19:28:09 +00:00
parent 4dd96a8315
commit 059b2d50e1
7 changed files with 143 additions and 47 deletions
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23
src/where.c
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@@ -1594,6 +1594,8 @@ static void constructAutomaticIndex(
Bitmask idxCols; /* Bitmap of columns used for indexing */
Bitmask extraCols; /* Bitmap of additional columns */
u8 sentWarning = 0; /* True if a warnning has been issued */
Expr *pPartial = 0; /* Partial Index Expression */
int iContinue = 0; /* Jump here to skip excluded rows */
/* Generate code to skip over the creation and initialization of the
** transient index on 2nd and subsequent iterations of the loop. */
@@ -1609,6 +1611,11 @@ static void constructAutomaticIndex(
pLoop = pLevel->pWLoop;
idxCols = 0;
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
if( pLoop->prereq==0
&& sqlite3ExprIsTableConstant(pTerm->pExpr, pSrc->iCursor) ){
pPartial = sqlite3ExprAnd(pParse->db, pPartial,
sqlite3ExprDup(pParse->db, pTerm->pExpr, 0));
}
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
int iCol = pTerm->u.leftColumn;
Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
@@ -1621,7 +1628,9 @@ static void constructAutomaticIndex(
sentWarning = 1;
}
if( (idxCols & cMask)==0 ){
if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ) return;
if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ){
goto end_auto_index_create;
}
pLoop->aLTerm[nKeyCol++] = pTerm;
idxCols |= cMask;
}
@@ -1654,7 +1663,7 @@ static void constructAutomaticIndex(
/* Construct the Index object to describe this index */
pIdx = sqlite3AllocateIndexObject(pParse->db, nKeyCol+1, 0, &zNotUsed);
if( pIdx==0 ) return;
if( pIdx==0 ) goto end_auto_index_create;
pLoop->u.btree.pIndex = pIdx;
pIdx->zName = "auto-index";
pIdx->pTable = pTable;
@@ -1706,18 +1715,28 @@ static void constructAutomaticIndex(
VdbeComment((v, "for %s", pTable->zName));
/* Fill the automatic index with content */
sqlite3ExprCachePush(pParse);
addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur); VdbeCoverage(v);
if( pPartial ){
iContinue = sqlite3VdbeMakeLabel(v);
sqlite3ExprIfFalse(pParse, pPartial, iContinue, SQLITE_JUMPIFNULL);
}
regRecord = sqlite3GetTempReg(pParse);
sqlite3GenerateIndexKey(pParse, pIdx, pLevel->iTabCur, regRecord, 0, 0, 0, 0);
sqlite3VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
if( pPartial ) sqlite3VdbeResolveLabel(v, iContinue);
sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1); VdbeCoverage(v);
sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX);
sqlite3VdbeJumpHere(v, addrTop);
sqlite3ReleaseTempReg(pParse, regRecord);
sqlite3ExprCachePop(pParse);
/* Jump here when skipping the initialization */
sqlite3VdbeJumpHere(v, addrInit);
end_auto_index_create:
sqlite3ExprDelete(pParse->db, pPartial);
}
#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */