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Overview
Comment:When generating individual loops for each ORed term of an OR scan, move any constant WHERE expressions outside of the loop, as is done for top-level loops.
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SHA3-256:e4a022be4b069b08cfdfda5295461676b99d28e17bbbedfbcb362dec69de59bd
User & Date: dan 2017-06-22 16:51:16
Context
2017-06-23
15:47
When generating individual loops for each ORed term of an OR scan, move any constant WHERE expressions outside of the loop, as is done for top-level loops. check-in: 712267c9 user: dan tags: trunk
2017-06-22
16:51
When generating individual loops for each ORed term of an OR scan, move any constant WHERE expressions outside of the loop, as is done for top-level loops. Closed-Leaf check-in: e4a022be user: dan tags: or-optimization
2017-06-21
01:36
Enable pragma virtual tables for the integrity_check, quick_check, and foreign_key_check pragmas. check-in: 118f7bb3 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/fkey.c.

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  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite3ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment either the deferred or immediate
  ** foreign key constraint counter. */

  pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
  sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite3WhereEnd(pWInfo);

  }

  /* Clean up the WHERE clause constructed above. */
  sqlite3ExprDelete(db, pWhere);
  if( iFkIfZero ){
    sqlite3VdbeJumpHere(v, iFkIfZero);
  }







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  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite3ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment either the deferred or immediate
  ** foreign key constraint counter. */
  if( pParse->nErr==0 ){
    pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
    if( pWInfo ){
      sqlite3WhereEnd(pWInfo);
    }
  }

  /* Clean up the WHERE clause constructed above. */
  sqlite3ExprDelete(db, pWhere);
  if( iFkIfZero ){
    sqlite3VdbeJumpHere(v, iFkIfZero);
  }

Changes to src/tclsqlite.c.

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  Tcl_Obj *pCollateNeeded;   /* Collation needed script */
  SqlPreparedStmt *stmtList; /* List of prepared statements*/
  SqlPreparedStmt *stmtLast; /* Last statement in the list */
  int maxStmt;               /* The next maximum number of stmtList */
  int nStmt;                 /* Number of statements in stmtList */
  IncrblobChannel *pIncrblob;/* Linked list of open incrblob channels */
  int nStep, nSort, nIndex;  /* Statistics for most recent operation */

  int nTransaction;          /* Number of nested [transaction] methods */
  int openFlags;             /* Flags used to open.  (SQLITE_OPEN_URI) */
#ifdef SQLITE_TEST
  int bLegacyPrepare;        /* True to use sqlite3_prepare() */
#endif
};

................................................................................
        dbEvalRowInfo(p, 0, 0);
      }
      rcs = sqlite3_reset(pStmt);

      pDb->nStep = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_FULLSCAN_STEP,1);
      pDb->nSort = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_SORT,1);
      pDb->nIndex = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_AUTOINDEX,1);

      dbReleaseColumnNames(p);
      p->pPreStmt = 0;

      if( rcs!=SQLITE_OK ){
        /* If a run-time error occurs, report the error and stop reading
        ** the SQL.  */
        dbReleaseStmt(pDb, pPreStmt, 1);
................................................................................
      rc = TCL_ERROR;
    }
    sqlite3_close(pSrc);
    break;
  }

  /*
  **     $db status (step|sort|autoindex)
  **
  ** Display SQLITE_STMTSTATUS_FULLSCAN_STEP or
  ** SQLITE_STMTSTATUS_SORT for the most recent eval.
  */
  case DB_STATUS: {
    int v;
    const char *zOp;
................................................................................
    zOp = Tcl_GetString(objv[2]);
    if( strcmp(zOp, "step")==0 ){
      v = pDb->nStep;
    }else if( strcmp(zOp, "sort")==0 ){
      v = pDb->nSort;
    }else if( strcmp(zOp, "autoindex")==0 ){
      v = pDb->nIndex;


    }else{
      Tcl_AppendResult(interp,
            "bad argument: should be autoindex, step, or sort",
            (char*)0);
      return TCL_ERROR;
    }
    Tcl_SetObjResult(interp, Tcl_NewIntObj(v));
    break;
  }








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  Tcl_Obj *pCollateNeeded;   /* Collation needed script */
  SqlPreparedStmt *stmtList; /* List of prepared statements*/
  SqlPreparedStmt *stmtLast; /* Last statement in the list */
  int maxStmt;               /* The next maximum number of stmtList */
  int nStmt;                 /* Number of statements in stmtList */
  IncrblobChannel *pIncrblob;/* Linked list of open incrblob channels */
  int nStep, nSort, nIndex;  /* Statistics for most recent operation */
  int nVMStep;               /* Another statistic for most recent operation */
  int nTransaction;          /* Number of nested [transaction] methods */
  int openFlags;             /* Flags used to open.  (SQLITE_OPEN_URI) */
#ifdef SQLITE_TEST
  int bLegacyPrepare;        /* True to use sqlite3_prepare() */
#endif
};

................................................................................
        dbEvalRowInfo(p, 0, 0);
      }
      rcs = sqlite3_reset(pStmt);

      pDb->nStep = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_FULLSCAN_STEP,1);
      pDb->nSort = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_SORT,1);
      pDb->nIndex = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_AUTOINDEX,1);
      pDb->nVMStep = sqlite3_stmt_status(pStmt,SQLITE_STMTSTATUS_VM_STEP,1);
      dbReleaseColumnNames(p);
      p->pPreStmt = 0;

      if( rcs!=SQLITE_OK ){
        /* If a run-time error occurs, report the error and stop reading
        ** the SQL.  */
        dbReleaseStmt(pDb, pPreStmt, 1);
................................................................................
      rc = TCL_ERROR;
    }
    sqlite3_close(pSrc);
    break;
  }

  /*
  **     $db status (step|sort|autoindex|vmstep)
  **
  ** Display SQLITE_STMTSTATUS_FULLSCAN_STEP or
  ** SQLITE_STMTSTATUS_SORT for the most recent eval.
  */
  case DB_STATUS: {
    int v;
    const char *zOp;
................................................................................
    zOp = Tcl_GetString(objv[2]);
    if( strcmp(zOp, "step")==0 ){
      v = pDb->nStep;
    }else if( strcmp(zOp, "sort")==0 ){
      v = pDb->nSort;
    }else if( strcmp(zOp, "autoindex")==0 ){
      v = pDb->nIndex;
    }else if( strcmp(zOp, "vmstep")==0 ){
      v = pDb->nVMStep;
    }else{
      Tcl_AppendResult(interp,
            "bad argument: should be autoindex, step, sort or vmstep",
            (char*)0);
      return TCL_ERROR;
    }
    Tcl_SetObjResult(interp, Tcl_NewIntObj(v));
    break;
  }

Changes to src/where.c.

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#ifdef SQLITE_DEBUG
    pLoop->cId = '0';
#endif
    return 1;
  }
  return 0;
}


























/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite3WhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
................................................................................
  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  sqlite3WhereClauseInit(&pWInfo->sWC, pWInfo);
  sqlite3WhereSplit(&pWInfo->sWC, pWhere, TK_AND);
    
  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  for(ii=0; ii<sWLB.pWC->nTerm; ii++){
    if( nTabList==0 || sqlite3ExprIsConstantNotJoin(sWLB.pWC->a[ii].pExpr) ){
      sqlite3ExprIfFalse(pParse, sWLB.pWC->a[ii].pExpr, pWInfo->iBreak,
                         SQLITE_JUMPIFNULL);
      sWLB.pWC->a[ii].wtFlags |= TERM_CODED;
    }
  }

  /* Special case: No FROM clause
  */
  if( nTabList==0 ){
    if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
    if( wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
................................................................................
    assert( m==MASKBIT(ii) );
  }
#endif

  /* Analyze all of the subexpressions. */
  sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
  if( db->mallocFailed ) goto whereBeginError;




















  if( wctrlFlags & WHERE_WANT_DISTINCT ){
    if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
      /* The DISTINCT marking is pointless.  Ignore it. */
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }else if( pOrderBy==0 ){
      /* Try to ORDER BY the result set to make distinct processing easier */







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#ifdef SQLITE_DEBUG
    pLoop->cId = '0';
#endif
    return 1;
  }
  return 0;
}

/*
** Helper function for exprIsDeterministic().
*/
static int exprNodeIsDeterministic(Walker *pWalker, Expr *pExpr){
  if( pExpr->op==TK_FUNCTION && ExprHasProperty(pExpr, EP_ConstFunc)==0 ){
    pWalker->eCode = 0;
    return WRC_Abort;
  }
  return WRC_Continue;
}

/*
** Return true if the expression contains no non-deterministic SQL 
** functions. Do not consider non-deterministic SQL functions that are 
** part of sub-select statements.
*/
static int exprIsDeterministic(Expr *p){
  Walker w;
  memset(&w, 0, sizeof(w));
  w.eCode = 1;
  w.xExprCallback = exprNodeIsDeterministic;
  sqlite3WalkExpr(&w, p);
  return w.eCode;
}

/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite3WhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
................................................................................
  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  sqlite3WhereClauseInit(&pWInfo->sWC, pWInfo);
  sqlite3WhereSplit(&pWInfo->sWC, pWhere, TK_AND);
    











  /* Special case: No FROM clause
  */
  if( nTabList==0 ){
    if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
    if( wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
................................................................................
    assert( m==MASKBIT(ii) );
  }
#endif

  /* Analyze all of the subexpressions. */
  sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
  if( db->mallocFailed ) goto whereBeginError;

  /* Special case: WHERE terms that do not refer to any tables in the join
  ** (constant expressions). Evaluate each such term, and jump over all the
  ** generated code if the result is not true.  
  **
  ** Do not do this if the expression contains non-deterministic functions
  ** that are not within a sub-select. This is not strictly required, but
  ** preserves SQLite's legacy behaviour in the following two cases:
  **
  **   FROM ... WHERE random()>0;           -- eval random() once per row
  **   FROM ... WHERE (SELECT random())>0;  -- eval random() once overall
  */
  for(ii=0; ii<sWLB.pWC->nTerm; ii++){
    WhereTerm *pT = &sWLB.pWC->a[ii];
    if( pT->prereqAll==0 && (nTabList==0 || exprIsDeterministic(pT->pExpr)) ){
      sqlite3ExprIfFalse(pParse, pT->pExpr, pWInfo->iBreak, SQLITE_JUMPIFNULL);
      pT->wtFlags |= TERM_CODED;
    }
  }

  if( wctrlFlags & WHERE_WANT_DISTINCT ){
    if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
      /* The DISTINCT marking is pointless.  Ignore it. */
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }else if( pOrderBy==0 ){
      /* Try to ORDER BY the result set to make distinct processing easier */

Changes to test/eqp.test.

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  0 0 0 {SCAN TABLE t1}
  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t1 AS sub}
}
do_eqp_test 3.1.2 {
  SELECT * FROM t1 WHERE (SELECT x FROM t1 AS sub);
} {
  0 0 0 {SCAN TABLE t1}
  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t1 AS sub}

}
do_eqp_test 3.1.3 {
  SELECT * FROM t1 WHERE (SELECT x FROM t1 AS sub ORDER BY y);
} {
  0 0 0 {SCAN TABLE t1}
  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t1 AS sub}
  1 0 0 {USE TEMP B-TREE FOR ORDER BY}

}
do_eqp_test 3.1.4 {
  SELECT * FROM t1 WHERE (SELECT x FROM t2 ORDER BY x);
} {
  0 0 0 {SCAN TABLE t1}
  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t2 USING COVERING INDEX t2i1}

}

det 3.2.1 {
  SELECT * FROM (SELECT * FROM t1 ORDER BY x LIMIT 10) ORDER BY y LIMIT 5
} {
  1 0 0 {SCAN TABLE t1} 
  1 0 0 {USE TEMP B-TREE FOR ORDER BY} 







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  0 0 0 {SCAN TABLE t1}
  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t1 AS sub}
}
do_eqp_test 3.1.2 {
  SELECT * FROM t1 WHERE (SELECT x FROM t1 AS sub);
} {

  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t1 AS sub}
  0 0 0 {SCAN TABLE t1}
}
do_eqp_test 3.1.3 {
  SELECT * FROM t1 WHERE (SELECT x FROM t1 AS sub ORDER BY y);
} {

  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t1 AS sub}
  1 0 0 {USE TEMP B-TREE FOR ORDER BY}
  0 0 0 {SCAN TABLE t1}
}
do_eqp_test 3.1.4 {
  SELECT * FROM t1 WHERE (SELECT x FROM t2 ORDER BY x);
} {

  0 0 0 {EXECUTE SCALAR SUBQUERY 1}
  1 0 0 {SCAN TABLE t2 USING COVERING INDEX t2i1}
  0 0 0 {SCAN TABLE t1}
}

det 3.2.1 {
  SELECT * FROM (SELECT * FROM t1 ORDER BY x LIMIT 10) ORDER BY y LIMIT 5
} {
  1 0 0 {SCAN TABLE t1} 
  1 0 0 {USE TEMP B-TREE FOR ORDER BY} 

Changes to test/whereF.test.

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do_execsql_test 4.0 {
  CREATE TABLE t4(a,b,c,d,e, PRIMARY KEY(a,b,c));
  CREATE INDEX t4adc ON t4(a,d,c);
  CREATE UNIQUE INDEX t4aebc ON t4(a,e,b,c);
  EXPLAIN QUERY PLAN SELECT rowid FROM t4 WHERE a=? AND b=?;
} {/a=. AND b=./}


























































finish_test








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do_execsql_test 4.0 {
  CREATE TABLE t4(a,b,c,d,e, PRIMARY KEY(a,b,c));
  CREATE INDEX t4adc ON t4(a,d,c);
  CREATE UNIQUE INDEX t4aebc ON t4(a,e,b,c);
  EXPLAIN QUERY PLAN SELECT rowid FROM t4 WHERE a=? AND b=?;
} {/a=. AND b=./}

#-------------------------------------------------------------------------
# Test the following case:
#
#   ... FROM t1, t2 WHERE (
#     t2.rowid = +t1.rowid OR (t2.f2 = t1.f1 AND t1.f1!=-1)
#   )
#
# where there is an index on t2(f2). The planner should use "t1" as the
# outer loop. The inner loop, on "t2", is an OR optimization. One pass
# for:
#
#     t2.rowid = $1
#
# and another for:
#
#     t2.f2=$1 AND $1!=-1
#
# the test is to ensure that on the second pass, the ($1!=-1) condition
# is tested before any seek operations are performed - i.e. outside of
# the loop through the f2=$1 range of the t2(f2) index.
#
reset_db
do_execsql_test 5.0 {
  CREATE TABLE t1(f1);
  CREATE TABLE t2(f2);
  CREATE INDEX t2f ON t2(f2);

  INSERT INTO t1 VALUES(-1);
  INSERT INTO t1 VALUES(-1);
  INSERT INTO t1 VALUES(-1);
  INSERT INTO t1 VALUES(-1);

  WITH w(i) AS (
    SELECT 1 UNION ALL SELECT i+1 FROM w WHERE i<1000
  )
  INSERT INTO t2 SELECT -1 FROM w;
}

do_execsql_test 5.1 {
  SELECT count(*) FROM t1, t2 WHERE t2.rowid = +t1.rowid
} {4}
do_test 5.2 { expr [db status vmstep]<200 } 1

do_execsql_test 5.3 {
  SELECT count(*) FROM t1, t2 WHERE (
    t2.rowid = +t1.rowid OR t2.f2 = t1.f1
  )
} {4000}
do_test 5.4 { expr [db status vmstep]>1000 } 1

do_execsql_test 5.5 {
  SELECT count(*) FROM t1, t2 WHERE (
    t2.rowid = +t1.rowid OR (t2.f2 = t1.f1 AND t1.f1!=-1)
  )
} {4}
do_test 5.6 { expr [db status vmstep]<200 } 1

finish_test