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Overview
| Comment: | Disable the [d1ba200234f40b84|count-of-view optimization] if any subquery is DISTINCT, as the optimization does not work in that case. Bug reported by forum post a860f5fb2e. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
d7013b63932b2f5750572ae6bdd259a2 |
| User & Date: | drh 2025-03-10 10:32:31 |
| Original Comment: | Disable the [d1ba200234f40b84|count-of-view optimization] if any subquery is DISTINCT, as the optimization does not work in that case. Bug reported by [forum/forumpost/a860f5fb2e|forum post a860f5fb2e]. |
Context
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2025-03-10
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| 17:28 | Add an explicit db close to test/walsetlk.test to work around an unjustified test failure on Windows when the walsetlk tests are run in the same invocation of testfixture.exe in Windows. (check-in: f418de10 user: stephan tags: trunk) | |
| 10:39 | Disable the [d1ba200234f40b84|count-of-view optimization] if any subquery is DISTINCT, as the optimization does not work in that case. (Leaf check-in: bae270b9 user: drh tags: branch-3.49) | |
| 10:32 | Disable the [d1ba200234f40b84|count-of-view optimization] if any subquery is DISTINCT, as the optimization does not work in that case. Bug reported by forum post a860f5fb2e. (check-in: d7013b63 user: drh tags: trunk) | |
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2025-03-06
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| 09:29 | Back out the most significant part of [5c28a17253e2f], as Cygwin is a hybrid. With SQLITE_OS_UNIX it will use POSIX locking, which will misinteract with apps using Windows-style locking. (check-in: 44adf8f3 user: stephan tags: trunk) | |
Changes
Changes to src/select.c.
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7197 7198 7199 7200 7201 7202 7203 7204 7205 7206 7207 7208 7209 7210 |
** The transformation only works if all of the following are true:
**
** * The subquery is a UNION ALL of two or more terms
** * The subquery does not have a LIMIT clause
** * There is no WHERE or GROUP BY or HAVING clauses on the subqueries
** * The outer query is a simple count(*) with no WHERE clause or other
** extraneous syntax.
**
** Return TRUE if the optimization is undertaken.
*/
static int countOfViewOptimization(Parse *pParse, Select *p){
Select *pSub, *pPrior;
Expr *pExpr;
Expr *pCount;
| > | 7197 7198 7199 7200 7201 7202 7203 7204 7205 7206 7207 7208 7209 7210 7211 |
** The transformation only works if all of the following are true:
**
** * The subquery is a UNION ALL of two or more terms
** * The subquery does not have a LIMIT clause
** * There is no WHERE or GROUP BY or HAVING clauses on the subqueries
** * The outer query is a simple count(*) with no WHERE clause or other
** extraneous syntax.
** * None of the subqueries are DISTINCT (forumpost/a860f5fb2e 2025-03-10)
**
** Return TRUE if the optimization is undertaken.
*/
static int countOfViewOptimization(Parse *pParse, Select *p){
Select *pSub, *pPrior;
Expr *pExpr;
Expr *pCount;
|
| ︙ | ︙ | |||
7229 7230 7231 7232 7233 7234 7235 |
pSub = pFrom->u4.pSubq->pSelect;
if( pSub->pPrior==0 ) return 0; /* Must be a compound */
if( pSub->selFlags & SF_CopyCte ) return 0; /* Not a CTE */
do{
if( pSub->op!=TK_ALL && pSub->pPrior ) return 0; /* Must be UNION ALL */
if( pSub->pWhere ) return 0; /* No WHERE clause */
if( pSub->pLimit ) return 0; /* No LIMIT clause */
| > | > > > | 7230 7231 7232 7233 7234 7235 7236 7237 7238 7239 7240 7241 7242 7243 7244 7245 7246 7247 7248 |
pSub = pFrom->u4.pSubq->pSelect;
if( pSub->pPrior==0 ) return 0; /* Must be a compound */
if( pSub->selFlags & SF_CopyCte ) return 0; /* Not a CTE */
do{
if( pSub->op!=TK_ALL && pSub->pPrior ) return 0; /* Must be UNION ALL */
if( pSub->pWhere ) return 0; /* No WHERE clause */
if( pSub->pLimit ) return 0; /* No LIMIT clause */
if( pSub->selFlags & (SF_Aggregate|SF_Distinct) ){
testcase( pSub->selFlags & SF_Aggregate );
testcase( pSub->selFlags & SF_Distinct );
return 0; /* Not an aggregate nor DISTINCT */
}
assert( pSub->pHaving==0 ); /* Due to the previous */
pSub = pSub->pPrior; /* Repeat over compound */
}while( pSub );
/* If we reach this point then it is OK to perform the transformation */
db = pParse->db;
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