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Overview
Comment:Avoid O(N*N) behavior with very long lists of VALUES.
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SHA1: ee30fb35217f3429ee89aaad7c19f29710420e4c
User & Date: drh 2015-01-05 20:04:51.191
Context
2015-01-05
20:13
Enhance "INSERT INTO ... VALUES" so that the number of rows in the VALUES clause is not limited by SQLITE_LIMIT_COMPOUND_SELECT, and so that the stack depth is constant regardless of the number of rows in VALUES. (check-in: e1c4a359aa user: drh tags: trunk)
20:04
Avoid O(N*N) behavior with very long lists of VALUES. (Closed-Leaf check-in: ee30fb3521 user: drh tags: many-VALUEs)
19:16
Handle compound-select statements originating from VALUES clauses as a special case that does not use recursion. (check-in: 9ce9e43af3 user: drh tags: many-VALUEs)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/select.c.
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    return WRC_Abort;
  }
  if( NEVER(p->pSrc==0) || (selFlags & SF_Expanded)!=0 ){
    return WRC_Prune;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;
  if( pWalker->xSelectCallback2==selectPopWith ){
  sqlite3WithPush(pParse, findRightmost(p)->pWith, 0);
    sqlite3WithPush(pParse, findRightmost(p)->pWith, 0);
  }

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, pTabList);

  /* Look up every table named in the FROM clause of the select.  If
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  w.xExprCallback = exprWalkNoop;
  w.pParse = pParse;
  if( pParse->hasCompound ){
    w.xSelectCallback = convertCompoundSelectToSubquery;
    sqlite3WalkSelect(&w, pSelect);
  }
  w.xSelectCallback = selectExpander;
  if( (pSelect->selFlags & SF_AllValues)==0 ){
  w.xSelectCallback2 = selectPopWith;
    w.xSelectCallback2 = selectPopWith;
  }
  sqlite3WalkSelect(&w, pSelect);
}


#ifndef SQLITE_OMIT_SUBQUERY
/*
** This is a Walker.xSelectCallback callback for the sqlite3SelectTypeInfo()
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