SQLite: Check-in [3dd35f51]

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Overview

Comment:	Increase the initial value of WhereLoopBuilder.iPlanLimit to 20K. Issue a warning if the iPlanLimit reaches zero.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| trunk
Files:	files \| file ages \| folders
SHA3-256:	3dd35f51187574f47f860405309877cdbf9dc5710703dfd98cf98073b771140c
User & Date:	drh 2018-09-24 10:47:33

Context

2018-09-24
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: 903e5018 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: 3dd35f51 user: drh tags: trunk
2018-09-23
02:01		Fix a faulty assert() in the validation logic for the LEFT JOIN strength reduction optimization. Problem found by OSSFuzz. check-in: 2fd62fcc user: drh tags: trunk

Changes

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Changes to src/where.c.


  /* Loop over the tables in the join, from left to right */
  pNew = pBuilder->pNew;
  whereLoopInit(pNew);
  /* Some pathological queries provide an unreasonable number of indexing
  ** options. The iPlanLimit value prevents these queries from taking up
  ** too much time in the planner. When iPlanLimit reaches zero, no further
  ** index+constraint options are considered. Seed iPlanLimit to 10K but
  ** also add an extra 1K to each table of the join, to ensure that each
  ** table at least gets 1K opportunities. */
  pBuilder->iPlanLimit = 10000;
  for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){
    Bitmask mUnusable = 0;
    pNew->iTab = iTab;
    pBuilder->iPlanLimit += 1000;  /* 1000 bonus for each table in the join */
    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
................................................................................
    if( rc==SQLITE_OK && pBuilder->pWC->hasOr ){
      rc = whereLoopAddOr(pBuilder, mPrereq, mUnusable);
    }
    mPrior |= pNew->maskSelf;
    if( rc || db->mallocFailed ){
      if( rc==SQLITE_DONE ){
        /* We hit the query planner search limit set by iPlanLimit */

        rc = SQLITE_OK;
      }else{
        break;
      }
    }
  }


  /* Loop over the tables in the join, from left to right */
  pNew = pBuilder->pNew;
  whereLoopInit(pNew);
  /* Some pathological queries provide an unreasonable number of indexing
  ** options. The iPlanLimit value prevents these queries from taking up
  ** too much time in the planner. When iPlanLimit reaches zero, no further
  ** index+constraint options are considered. Seed iPlanLimit to 20K but
  ** also add an extra 1K to each table of the join, to ensure that each
  ** table at least gets 1K opportunities. */
  pBuilder->iPlanLimit = 20000;
  for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){
    Bitmask mUnusable = 0;
    pNew->iTab = iTab;
    pBuilder->iPlanLimit += 1000;  /* 1000 bonus for each table in the join */
    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
................................................................................
    if( rc==SQLITE_OK && pBuilder->pWC->hasOr ){
      rc = whereLoopAddOr(pBuilder, mPrereq, mUnusable);
    }
    mPrior |= pNew->maskSelf;
    if( rc || db->mallocFailed ){
      if( rc==SQLITE_DONE ){
        /* We hit the query planner search limit set by iPlanLimit */
        sqlite3_log(SQLITE_WARNING, "abbreviated query algorithm search");
        rc = SQLITE_OK;
      }else{
        break;
      }
    }
  }