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Fix issues in [/info/1e227ad9f413227f|LIMIT/OFFSET support for virtual tables].

Browse Source 
The first problem was reported by
[forum:/forumpost/c243b8f856|forum post c243b8f856].  That report prompted
an enhancement to the generate_series() (also included in this merge) which
in turn identified other similar issues.

FossilOrigin-Name: 5f6c079d847e3664ec5acaf1b3e989efe0d548c211ae4a18936162b36df89065
This commit is contained in:
drh
2024-04-26 19:10:15 +00:00
parent b95c1d0ac9 4c3ab545a9
commit b11daa50f9
8 changed files with 328 additions and 45 deletions
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30
src/where.c
View File

@ -4057,6 +4057,21 @@ static int isLimitTerm(WhereTerm *pTerm){
&& pTerm->eMatchOp<=SQLITE_INDEX_CONSTRAINT_OFFSET;
}
/*
** Return true if the first nCons constraints in the pUsage array are
** marked as in-use (have argvIndex>0). False otherwise.
*/
static int allConstraintsUsed(
struct sqlite3_index_constraint_usage *aUsage,
int nCons
){
int ii;
for(ii=0; ii<nCons; ii++){
if( aUsage[ii].argvIndex<=0 ) return 0;
}
return 1;
}
/*
** Argument pIdxInfo is already populated with all constraints that may
** be used by the virtual table identified by pBuilder->pNew->iTab. This
@ -4197,13 +4212,20 @@ static int whereLoopAddVirtualOne(
*pbIn = 1; assert( (mExclude & WO_IN)==0 );
}
/* Unless pbRetryLimit is non-NULL, there should be no LIMIT/OFFSET
** terms. And if there are any, they should follow all other terms. */
assert( pbRetryLimit || !isLimitTerm(pTerm) );
if( isLimitTerm(pTerm) && *pbIn ){
assert( !isLimitTerm(pTerm) || i>=nConstraint-2 );
assert( !isLimitTerm(pTerm) || i==nConstraint-1 || isLimitTerm(pTerm+1) );
if( isLimitTerm(pTerm) && (*pbIn || !allConstraintsUsed(pUsage, i)) ){
/* If there is an IN(...) term handled as an == (separate call to
** xFilter for each value on the RHS of the IN) and a LIMIT or
** OFFSET term handled as well, the plan is unusable. Set output
** variable *pbRetryLimit to true to tell the caller to retry with
** LIMIT and OFFSET disabled. */
** OFFSET term handled as well, the plan is unusable. Similarly,
** if there is a LIMIT/OFFSET and there are other unused terms,
** the plan cannot be used. In these cases set variable *pbRetryLimit
** to true to tell the caller to retry with LIMIT and OFFSET
** disabled. */
if( pIdxInfo->needToFreeIdxStr ){
sqlite3_free(pIdxInfo->idxStr);
pIdxInfo->idxStr = 0;

9
src/whereexpr.c
View File

@ -1638,6 +1638,7 @@ void SQLITE_NOINLINE sqlite3WhereAddLimit(WhereClause *pWC, Select *p){
continue;
}
if( pWC->a[ii].leftCursor!=iCsr ) return;
if( pWC->a[ii].prereqRight!=0 ) return;
}
/* Check condition (5). Return early if it is not met. */
@ -1652,12 +1653,14 @@ void SQLITE_NOINLINE sqlite3WhereAddLimit(WhereClause *pWC, Select *p){
/* All conditions are met. Add the terms to the where-clause object. */
assert( p->pLimit->op==TK_LIMIT );
whereAddLimitExpr(pWC, p->iLimit, p->pLimit->pLeft,
iCsr, SQLITE_INDEX_CONSTRAINT_LIMIT);
if( p->iOffset>0 ){
if( p->iOffset!=0 && (p->selFlags & SF_Compound)==0 ){
whereAddLimitExpr(pWC, p->iOffset, p->pLimit->pRight,
iCsr, SQLITE_INDEX_CONSTRAINT_OFFSET);
}
if( p->iOffset==0 || (p->selFlags & SF_Compound)==0 ){
whereAddLimitExpr(pWC, p->iLimit, p->pLimit->pLeft,
iCsr, SQLITE_INDEX_CONSTRAINT_LIMIT);
}
}
}