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Overview
| Comment: | Use compile-time options SQLITE_QUERY_PLANNER_LIMIT and SQLITE_QUERY_PLANNER_LIMIT_INCR to control the value for WhereLoopBuilder.iPlanLimit, rather than embedding magic numbers in the code. |
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| Files: | files | file ages | folders |
| SHA3-256: |
903e501894b2a5dd7055b5154d74d4a4 |
| User & Date: | drh 2018-09-24 12:37:01.477 |
Context
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2018-09-24
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| 14:10 | Allow a writable virtual table to have a schema with an INTEGER PRIMARY KEY and WITHOUT ROWID. This fixes ticket [f25d5ceebe1d710ff61a571e395356869d8272ef]. Test case in TH3. (check-in: 5a38d9281b user: drh tags: trunk) | |
| 12:37 | Use compile-time options SQLITE_QUERY_PLANNER_LIMIT and SQLITE_QUERY_PLANNER_LIMIT_INCR to control the value for WhereLoopBuilder.iPlanLimit, rather than embedding magic numbers in the code. (check-in: 903e501894 user: drh tags: trunk) | |
| 10:47 | Increase the initial value of WhereLoopBuilder.iPlanLimit to 20K. Issue a warning if the iPlanLimit reaches zero. (check-in: 3dd35f5118 user: drh tags: trunk) | |
Changes
Changes to src/where.c.
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3536 3537 3538 3539 3540 3541 3542 | int rc = SQLITE_OK; WhereLoop *pNew; u8 priorJointype = 0; /* Loop over the tables in the join, from left to right */ pNew = pBuilder->pNew; whereLoopInit(pNew); | < < < < < < | | | 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 |
int rc = SQLITE_OK;
WhereLoop *pNew;
u8 priorJointype = 0;
/* Loop over the tables in the join, from left to right */
pNew = pBuilder->pNew;
whereLoopInit(pNew);
pBuilder->iPlanLimit = SQLITE_QUERY_PLANNER_LIMIT;
for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){
Bitmask mUnusable = 0;
pNew->iTab = iTab;
pBuilder->iPlanLimit += SQLITE_QUERY_PLANNER_LIMIT_INCR;
pNew->maskSelf = sqlite3WhereGetMask(&pWInfo->sMaskSet, pItem->iCursor);
if( ((pItem->fg.jointype|priorJointype) & (JT_LEFT|JT_CROSS))!=0 ){
/* This condition is true when pItem is the FROM clause term on the
** right-hand-side of a LEFT or CROSS JOIN. */
mPrereq = mPrior;
}
priorJointype = pItem->fg.jointype;
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Changes to src/whereInt.h.
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404 405 406 407 408 409 410 411 412 413 414 415 416 417 | unsigned int bldFlags; /* SQLITE_BLDF_* flags */ unsigned int iPlanLimit; /* Search limiter */ }; /* Allowed values for WhereLoopBuider.bldFlags */ #define SQLITE_BLDF_INDEXED 0x0001 /* An index is used */ #define SQLITE_BLDF_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ /* ** The WHERE clause processing routine has two halves. The ** first part does the start of the WHERE loop and the second ** half does the tail of the WHERE loop. An instance of ** this structure is returned by the first half and passed ** into the second half to give some continuity. | > > > > > > > > > > > > > > > > > > > > | 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 | unsigned int bldFlags; /* SQLITE_BLDF_* flags */ unsigned int iPlanLimit; /* Search limiter */ }; /* Allowed values for WhereLoopBuider.bldFlags */ #define SQLITE_BLDF_INDEXED 0x0001 /* An index is used */ #define SQLITE_BLDF_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ /* The WhereLoopBuilder.iPlanLimit is used to limit the number of ** index+constraint combinations the query planner will consider for a ** particular query. If this parameter is unlimited, then certain ** pathological queries can spend excess time in the sqlite3WhereBegin() ** routine. The limit is high enough that is should not impact real-world ** queries. ** ** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is ** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM ** clause is processed, so that every table in a join is guaranteed to be ** able to propose a some index+constraint combinations even if the initial ** baseline limit was exhausted by prior tables of the join. */ #ifndef SQLITE_QUERY_PLANNER_LIMIT # define SQLITE_QUERY_PLANNER_LIMIT 20000 #endif #ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR # define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000 #endif /* ** The WHERE clause processing routine has two halves. The ** first part does the start of the WHERE loop and the second ** half does the tail of the WHERE loop. An instance of ** this structure is returned by the first half and passed ** into the second half to give some continuity. |
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