}
#ifndef SQLITE_OMIT_VIRTUALTABLE
+
+/*
+** Argument pIdxInfo is already populated with all constraints that may
+** be used by the virtual table identified by pBuilder->pNew->iTab. This
+** function marks a subset of those constraints usable, invokes the
+** xBestIndex method and adds the returned plan to pBuilder.
+**
+** A constraint is marked usable if:
+**
+** * Argument mUsable indicates that its prerequisites are available, and
+**
+** * It is not one of the operators specified in the mExclude mask passed
+** as the fourth argument (which in practice is either WO_IN or 0).
+**
+** Argument mExtra is a mask of tables that must be scanned before the
+** virtual table in question. These are added to the plans prerequisites
+** before it is added to pBuilder.
+**
+** Output parameter *pbIn is set to true if the plan added to pBuilder
+** uses one or more WO_IN terms, or false otherwise.
+*/
+static int whereLoopAddVirtualOne(
+ WhereLoopBuilder *pBuilder,
+ Bitmask mExtra, /* Mask of tables that must be used. */
+ Bitmask mUsable, /* Mask of usable prereqs */
+ u16 mExclude, /* Exclude terms for this operator */
+ sqlite3_index_info *pIdxInfo, /* Populated object for xBestIndex */
+ int *pbIn /* OUT: True if plan uses an IN(...) op */
+){
+ WhereClause *pWC = pBuilder->pWC;
+ struct sqlite3_index_constraint *pIdxCons;
+ struct sqlite3_index_constraint_usage *pUsage = pIdxInfo->aConstraintUsage;
+ int i;
+ int mxTerm;
+ int rc = SQLITE_OK;
+ WhereLoop *pNew = pBuilder->pNew;
+ Parse *pParse = pBuilder->pWInfo->pParse;
+ struct SrcList_item *pSrc = &pBuilder->pWInfo->pTabList->a[pNew->iTab];
+ int nConstraint = pIdxInfo->nConstraint;
+
+ assert( (mUsable & mExtra)==mExtra );
+ *pbIn = 0;
+ pNew->prereq = mExtra;
+
+ /* Set the usable flag on the subset of constraints identified by
+ ** arguments mUsable and mExclude. */
+ pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
+ for(i=0; i<nConstraint; i++, pIdxCons++){
+ WhereTerm *pTerm = &pWC->a[pIdxCons->iTermOffset];
+ pIdxCons->usable = 0;
+ if( (pTerm->prereqRight & mUsable)==pTerm->prereqRight
+ && (pTerm->eOperator & mExclude)==0
+ ){
+ pIdxCons->usable = 1;
+ }
+ }
+
+ /* Initialize the output fields of the sqlite3_index_info structure */
+ memset(pUsage, 0, sizeof(pUsage[0])*nConstraint);
+ if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr);
+ pIdxInfo->idxStr = 0;
+ pIdxInfo->idxNum = 0;
+ pIdxInfo->needToFreeIdxStr = 0;
+ pIdxInfo->orderByConsumed = 0;
+ pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2;
+ pIdxInfo->estimatedRows = 25;
+ pIdxInfo->idxFlags = 0;
+ pIdxInfo->colUsed = (sqlite3_int64)pSrc->colUsed;
+
+ /* Invoke the virtual table xBestIndex() method */
+ rc = vtabBestIndex(pParse, pSrc->pTab, pIdxInfo);
+ if( rc ) return rc;
+
+ mxTerm = -1;
+ assert( pNew->nLSlot>=nConstraint );
+ for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 0;
+ pNew->u.vtab.omitMask = 0;
+ pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
+ for(i=0; i<nConstraint; i++, pIdxCons++){
+ int iTerm;
+ if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
+ WhereTerm *pTerm;
+ int j = pIdxCons->iTermOffset;
+ if( iTerm>=nConstraint
+ || j<0
+ || j>=pWC->nTerm
+ || pNew->aLTerm[iTerm]!=0
+ ){
+ rc = SQLITE_ERROR;
+ sqlite3ErrorMsg(pParse,"%s.xBestIndex() malfunction",pSrc->pTab->zName);
+ return rc;
+ }
+ testcase( iTerm==nConstraint-1 );
+ testcase( j==0 );
+ testcase( j==pWC->nTerm-1 );
+ pTerm = &pWC->a[j];
+ pNew->prereq |= pTerm->prereqRight;
+ assert( iTerm<pNew->nLSlot );
+ pNew->aLTerm[iTerm] = pTerm;
+ if( iTerm>mxTerm ) mxTerm = iTerm;
+ testcase( iTerm==15 );
+ testcase( iTerm==16 );
+ if( iTerm<16 && pUsage[i].omit ) pNew->u.vtab.omitMask |= 1<<iTerm;
+ if( (pTerm->eOperator & WO_IN)!=0 ){
+ /* A virtual table that is constrained by an IN clause may not
+ ** consume the ORDER BY clause because (1) the order of IN terms
+ ** is not necessarily related to the order of output terms and
+ ** (2) Multiple outputs from a single IN value will not merge
+ ** together. */
+ pIdxInfo->orderByConsumed = 0;
+ pIdxInfo->idxFlags &= ~SQLITE_INDEX_SCAN_UNIQUE;
+ *pbIn = 1;
+ }
+ }
+ }
+
+ pNew->nLTerm = mxTerm+1;
+ assert( pNew->nLTerm<=pNew->nLSlot );
+ pNew->u.vtab.idxNum = pIdxInfo->idxNum;
+ pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
+ pIdxInfo->needToFreeIdxStr = 0;
+ pNew->u.vtab.idxStr = pIdxInfo->idxStr;
+ pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ?
+ pIdxInfo->nOrderBy : 0);
+ pNew->rSetup = 0;
+ pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
+ pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
+
+ /* Set the WHERE_ONEROW flag if the xBestIndex() method indicated
+ ** that the scan will visit at most one row. Clear it otherwise. */
+ if( pIdxInfo->idxFlags & SQLITE_INDEX_SCAN_UNIQUE ){
+ pNew->wsFlags |= WHERE_ONEROW;
+ }else{
+ pNew->wsFlags &= ~WHERE_ONEROW;
+ }
+ whereLoopInsert(pBuilder, pNew);
+ if( pNew->u.vtab.needFree ){
+ sqlite3_free(pNew->u.vtab.idxStr);
+ pNew->u.vtab.needFree = 0;
+ }
+
+ return SQLITE_OK;
+}
+
+
/*
** Add all WhereLoop objects for a table of the join identified by
** pBuilder->pNew->iTab. That table is guaranteed to be a virtual table.
Bitmask mExtra, /* Tables that must be scanned before this one */
Bitmask mUnusable /* Tables that must be scanned after this one */
){
+ int rc = SQLITE_OK; /* Return code */
WhereInfo *pWInfo; /* WHERE analysis context */
Parse *pParse; /* The parsing context */
WhereClause *pWC; /* The WHERE clause */
struct SrcList_item *pSrc; /* The FROM clause term to search */
- Table *pTab;
- sqlite3 *db;
- sqlite3_index_info *pIdxInfo;
- struct sqlite3_index_constraint *pIdxCons;
- struct sqlite3_index_constraint_usage *pUsage;
- WhereTerm *pTerm;
- int i, j;
- int iTerm, mxTerm;
- int nConstraint;
- int seenIn = 0; /* True if an IN operator is seen */
- int seenVar = 0; /* True if a non-constant constraint is seen */
- int iPhase; /* 0: const w/o IN, 1: const, 2: no IN, 2: IN */
+ sqlite3_index_info *p; /* Object to pass to xBestIndex() */
+ int nConstraint; /* Number of constraints in p */
+ int bIn; /* True if plan uses IN(...) operator */
WhereLoop *pNew;
- int rc = SQLITE_OK;
+ Bitmask mBest; /* Tables used by best possible plan */
assert( (mExtra & mUnusable)==0 );
pWInfo = pBuilder->pWInfo;
pParse = pWInfo->pParse;
- db = pParse->db;
pWC = pBuilder->pWC;
pNew = pBuilder->pNew;
pSrc = &pWInfo->pTabList->a[pNew->iTab];
- pTab = pSrc->pTab;
- assert( IsVirtual(pTab) );
- pIdxInfo = allocateIndexInfo(pParse, pWC, mUnusable, pSrc,pBuilder->pOrderBy);
- if( pIdxInfo==0 ) return SQLITE_NOMEM_BKPT;
- pNew->prereq = 0;
+ assert( IsVirtual(pSrc->pTab) );
+ p = allocateIndexInfo(pParse, pWC, mUnusable, pSrc,pBuilder->pOrderBy);
+ if( p==0 ) return SQLITE_NOMEM_BKPT;
pNew->rSetup = 0;
pNew->wsFlags = WHERE_VIRTUALTABLE;
pNew->nLTerm = 0;
pNew->u.vtab.needFree = 0;
- pUsage = pIdxInfo->aConstraintUsage;
- nConstraint = pIdxInfo->nConstraint;
- if( whereLoopResize(db, pNew, nConstraint) ){
- sqlite3DbFree(db, pIdxInfo);
+ nConstraint = p->nConstraint;
+ if( whereLoopResize(pParse->db, pNew, nConstraint) ){
+ sqlite3DbFree(pParse->db, p);
return SQLITE_NOMEM_BKPT;
}
- for(iPhase=0; iPhase<=3; iPhase++){
- if( !seenIn && (iPhase&1)!=0 ){
- iPhase++;
- if( iPhase>3 ) break;
- }
- if( !seenVar && iPhase>1 ) break;
- pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
- for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
- j = pIdxCons->iTermOffset;
- pTerm = &pWC->a[j];
- switch( iPhase ){
- case 0: /* Constants without IN operator */
- pIdxCons->usable = 0;
- if( (pTerm->eOperator & WO_IN)!=0 ){
- seenIn = 1;
- }
- if( (pTerm->prereqRight & ~mExtra)!=0 ){
- seenVar = 1;
- }else if( (pTerm->eOperator & WO_IN)==0 ){
- pIdxCons->usable = 1;
- }
- break;
- case 1: /* Constants with IN operators */
- assert( seenIn );
- pIdxCons->usable = (pTerm->prereqRight & ~mExtra)==0;
- break;
- case 2: /* Variables without IN */
- assert( seenVar );
- pIdxCons->usable = (pTerm->eOperator & WO_IN)==0;
- break;
- default: /* Variables with IN */
- assert( seenVar && seenIn );
- pIdxCons->usable = 1;
- break;
- }
- }
- memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
- if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr);
- pIdxInfo->idxStr = 0;
- pIdxInfo->idxNum = 0;
- pIdxInfo->needToFreeIdxStr = 0;
- pIdxInfo->orderByConsumed = 0;
- pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2;
- pIdxInfo->estimatedRows = 25;
- pIdxInfo->idxFlags = 0;
- pIdxInfo->colUsed = (sqlite3_int64)pSrc->colUsed;
- rc = vtabBestIndex(pParse, pTab, pIdxInfo);
- if( rc ) goto whereLoopAddVtab_exit;
- pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
- pNew->prereq = mExtra;
- mxTerm = -1;
- assert( pNew->nLSlot>=nConstraint );
- for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 0;
- pNew->u.vtab.omitMask = 0;
- for(i=0; i<nConstraint; i++, pIdxCons++){
- if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
- j = pIdxCons->iTermOffset;
- if( iTerm>=nConstraint
- || j<0
- || j>=pWC->nTerm
- || pNew->aLTerm[iTerm]!=0
- ){
- rc = SQLITE_ERROR;
- sqlite3ErrorMsg(pParse, "%s.xBestIndex() malfunction", pTab->zName);
- goto whereLoopAddVtab_exit;
- }
- testcase( iTerm==nConstraint-1 );
- testcase( j==0 );
- testcase( j==pWC->nTerm-1 );
- pTerm = &pWC->a[j];
- pNew->prereq |= pTerm->prereqRight;
- assert( iTerm<pNew->nLSlot );
- pNew->aLTerm[iTerm] = pTerm;
- if( iTerm>mxTerm ) mxTerm = iTerm;
- testcase( iTerm==15 );
- testcase( iTerm==16 );
- if( iTerm<16 && pUsage[i].omit ) pNew->u.vtab.omitMask |= 1<<iTerm;
- if( (pTerm->eOperator & WO_IN)!=0 ){
- /* A virtual table that is constrained by an IN clause may not
- ** consume the ORDER BY clause because (1) the order of IN terms
- ** is not necessarily related to the order of output terms and
- ** (2) Multiple outputs from a single IN value will not merge
- ** together. */
- pIdxInfo->orderByConsumed = 0;
- pIdxInfo->idxFlags &= ~SQLITE_INDEX_SCAN_UNIQUE;
- }
+ /* First call xBestIndex() with all constraints usable. */
+ rc = whereLoopAddVirtualOne(pBuilder, mExtra, (Bitmask)(-1), 0, p, &bIn);
+ mBest = pNew->prereq & ~mExtra;
+
+ /* If the call to xBestIndex() with all terms enabled produced a plan
+ ** that does not require any source tables, there is no point in making
+ ** any further calls - if the xBestIndex() method is sane they will all
+ ** return the same plan anyway.
+ */
+ if( mBest ){
+ int seenZero = 0; /* True if a plan with no prereqs seen */
+ int seenZeroNoIN = 0; /* Plan with no prereqs and no IN(...) seen */
+ Bitmask mPrev = 0;
+ Bitmask mBestNoIn = 0;
+
+ /* If the plan produced by the earlier call uses an IN(...) term, call
+ ** xBestIndex again, this time with IN(...) terms disabled. */
+ if( rc==SQLITE_OK && bIn ){
+ rc = whereLoopAddVirtualOne(pBuilder, mExtra, (Bitmask)-1, WO_IN, p,&bIn);
+ mBestNoIn = pNew->prereq & ~mExtra;
+ if( mBestNoIn==0 ){
+ seenZero = 1;
+ if( bIn==0 ) seenZeroNoIN = 1;
}
}
- if( i>=nConstraint ){
- pNew->nLTerm = mxTerm+1;
- assert( pNew->nLTerm<=pNew->nLSlot );
- pNew->u.vtab.idxNum = pIdxInfo->idxNum;
- pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
- pIdxInfo->needToFreeIdxStr = 0;
- pNew->u.vtab.idxStr = pIdxInfo->idxStr;
- pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ?
- pIdxInfo->nOrderBy : 0);
- pNew->rSetup = 0;
- pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
- pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);
- /* Set the WHERE_ONEROW flag if the xBestIndex() method indicated
- ** that the scan will visit at most one row. Clear it otherwise. */
- if( pIdxInfo->idxFlags & SQLITE_INDEX_SCAN_UNIQUE ){
- pNew->wsFlags |= WHERE_ONEROW;
- }else{
- pNew->wsFlags &= ~WHERE_ONEROW;
+ /* Call xBestIndex once for each distinct value of (prereqRight & ~mExtra)
+ ** in the set of terms that apply to the current virtual table. */
+ while( rc==SQLITE_OK ){
+ int i;
+ Bitmask mNext = (Bitmask)(-1);
+ assert( mNext>0 );
+ for(i=0; i<nConstraint; i++){
+ Bitmask mThis = (
+ pWC->a[p->aConstraint[i].iTermOffset].prereqRight & ~mExtra
+ );
+ if( mThis>mPrev && mThis<mNext ) mNext = mThis;
}
- whereLoopInsert(pBuilder, pNew);
- if( pNew->u.vtab.needFree ){
- sqlite3_free(pNew->u.vtab.idxStr);
- pNew->u.vtab.needFree = 0;
+ mPrev = mNext;
+ if( mNext==(Bitmask)(-1) ) break;
+ if( mNext==mBest || mNext==mBestNoIn ) continue;
+ rc = whereLoopAddVirtualOne(pBuilder, mExtra, mNext, 0, p, &bIn);
+ if( pNew->prereq==mExtra ){
+ seenZero = 1;
+ if( bIn==0 ) seenZeroNoIN = 1;
}
}
- }
-whereLoopAddVtab_exit:
- if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr);
- sqlite3DbFree(db, pIdxInfo);
+ /* If the calls to xBestIndex() in the above loop did not find a plan
+ ** that requires no source tables at all (i.e. one guaranteed to be
+ ** usable), make a call here with all source tables disabled */
+ if( rc==SQLITE_OK && seenZero==0 ){
+ rc = whereLoopAddVirtualOne(pBuilder, mExtra, mExtra, 0, p, &bIn);
+ if( bIn==0 ) seenZeroNoIN = 1;
+ }
+
+ /* If the calls to xBestIndex() have so far failed to find a plan
+ ** that requires no source tables at all and does not use an IN(...)
+ ** operator, make a final call to obtain one here. */
+ if( rc==SQLITE_OK && seenZeroNoIN==0 ){
+ rc = whereLoopAddVirtualOne(pBuilder, mExtra, mExtra, WO_IN, p, &bIn);
+ }
+ }
+
+ if( p->needToFreeIdxStr ) sqlite3_free(p->idxStr);
+ sqlite3DbFree(pParse->db, p);
return rc;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */
--- /dev/null
+# 2016 March 3
+#
+# The author disclaims copyright to this source code. In place of
+# a legal notice, here is a blessing:
+#
+# May you do good and not evil.
+# May you find forgiveness for yourself and forgive others.
+# May you share freely, never taking more than you give.
+#
+#***********************************************************************
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix bestindex2
+
+
+#-------------------------------------------------------------------------
+# Virtual table callback for table named $tbl, with the columns specified
+# by list argument $cols. e.g. if the function is invoked as:
+#
+# vtab_cmd t1 {a b c} ...
+#
+# The table created is:
+#
+# "CREATE TABLE t1 (a, b, c)"
+#
+# The tables xBestIndex method behaves as if all possible combinations of
+# "=" constraints (but no others) may be optimized. The cost of a full table
+# scan is:
+#
+# "WHERE 1" "cost 1000000 rows 1000000"
+#
+# If one or more "=" constraints are in use, the cost and estimated number
+# of rows returned are both is (11 - nCons)*1000, where nCons is the number
+# of constraints used. e.g.
+#
+# "WHERE a=? AND b=?" -> "cost 900 rows 900"
+# "WHERE c=? AND b<?" -> "cost 1000 rows 1000"
+#
+proc vtab_cmd {tbl cols method args} {
+ switch -- $method {
+ xConnect {
+ return "CREATE TABLE $tbl ([join $cols ,])"
+ }
+ xBestIndex {
+ foreach {clist orderby mask} $args {}
+
+ set cons [list]
+ set used [list]
+
+ for {set i 0} {$i < [llength $clist]} {incr i} {
+ array unset C
+ array set C [lindex $clist $i]
+ if {$C(op)=="eq" && $C(usable) && [lsearch $cons $C(column)]<0} {
+ lappend used use $i
+ lappend cons $C(column)
+ }
+ }
+
+ set nCons [llength $cons]
+ if {$nCons==0} {
+ return "cost 1000000 rows 1000000"
+ } else {
+ set cost [expr (11-$nCons) * 1000]
+ set ret [concat $used "cost $cost rows $cost"]
+
+ set txt [list]
+ foreach c $cons { lappend txt "[lindex $cols $c]=?" }
+ lappend ret idxstr "indexed([join $txt { AND }])"
+
+ return $ret
+ }
+ }
+ }
+ return ""
+}
+
+register_tcl_module db
+
+do_execsql_test 1.0 {
+ CREATE VIRTUAL TABLE t1 USING tcl("vtab_cmd t1 {a b}");
+ CREATE VIRTUAL TABLE t2 USING tcl("vtab_cmd t2 {c d}");
+ CREATE VIRTUAL TABLE t3 USING tcl("vtab_cmd t3 {e f}");
+}
+
+do_eqp_test 1.1 {
+ SELECT * FROM t1 WHERE a='abc'
+} {
+ 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:indexed(a=?)}
+}
+do_eqp_test 1.2 {
+ SELECT * FROM t1 WHERE a='abc' AND b='def'
+} {
+ 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:indexed(a=? AND b=?)}
+}
+do_eqp_test 1.3 {
+ SELECT * FROM t1 WHERE a='abc' AND a='def'
+} {
+ 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:indexed(a=?)}
+}
+do_eqp_test 1.4 {
+ SELECT * FROM t1,t2 WHERE c=a
+} {
+ 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:}
+ 0 1 1 {SCAN TABLE t2 VIRTUAL TABLE INDEX 0:indexed(c=?)}
+}
+
+do_eqp_test 1.5 {
+ SELECT * FROM t1, t2 CROSS JOIN t3 WHERE t2.c = +t1.b AND t3.e=t2.d
+} {
+ 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:}
+ 0 1 1 {SCAN TABLE t2 VIRTUAL TABLE INDEX 0:indexed(c=?)}
+ 0 2 2 {SCAN TABLE t3 VIRTUAL TABLE INDEX 0:indexed(e=?)}
+}
+
+# This is the one that fails (as of 2016/3/3).
+#
+do_eqp_test 1.6 {
+ SELECT * FROM t1, t2, t3 WHERE t2.c = +t1.b AND t3.e = t2.d
+} {
+ 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:}
+ 0 1 1 {SCAN TABLE t2 VIRTUAL TABLE INDEX 0:indexed(c=?)}
+ 0 2 2 {SCAN TABLE t3 VIRTUAL TABLE INDEX 0:indexed(e=?)}
+}
+
+finish_test
+
projects / thirdparty / sqlite.git / commitdiff
