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authorMarc G. Fournier1998-09-04 12:52:23 +0000
committerMarc G. Fournier1998-09-04 12:52:23 +0000
commit370d6cdb64dfd571b9614263035f82eeb7a0aa1e (patch)
treec804567d4b16b9bc1eccf938b53d953014df4e50
parente9d0fa3762fd3731117c5ba0fee719771aacfd98 (diff)
From: David Hartwig <[email protected]>
I put some extra checks to make sure a query was a good candidate for rewrite into a UNION. Besides the existing checks: 1. Make sure the AND/OR tree was rectangular. ( i.e. 3 X 4 or 10 X 3) 2. Only one table. 3. Must have an AND dimension. 4. At least 9 OP expressions total Also cleaned up and commented.
-rw-r--r--src/backend/optimizer/prep/prepkeyset.c110
1 files changed, 55 insertions, 55 deletions
diff --git a/src/backend/optimizer/prep/prepkeyset.c b/src/backend/optimizer/prep/prepkeyset.c
index a8301a8f945..406c6929d0e 100644
--- a/src/backend/optimizer/prep/prepkeyset.c
+++ b/src/backend/optimizer/prep/prepkeyset.c
@@ -11,35 +11,20 @@
#include <string.h>
#include "postgres.h"
-#include "nodes/pg_list.h"
-#include "nodes/parsenodes.h"
-#include "utils/elog.h"
-
-#include "nodes/nodes.h"
-#include "nodes/execnodes.h"
-#include "nodes/plannodes.h"
-#include "nodes/primnodes.h"
-#include "nodes/relation.h"
-
-#include "catalog/pg_type.h"
-#include "lib/stringinfo.h"
#include "optimizer/planmain.h"
+
/*
* Node_Copy--
* a macro to simplify calling of copyObject on the specified field
*/
#define Node_Copy(from, newnode, field) newnode->field = copyObject(from->field)
-/***** DEBUG stuff
-#define TABS {int i; printf("\n"); for (i = 0; i<level; i++) printf("\t"); }
-static int level = 0;
-******/
-
bool _use_keyset_query_optimizer = FALSE;
static int inspectOpNode(Expr *expr);
static int inspectAndNode(Expr *expr);
static int inspectOrNode(Expr *expr);
+static int TotalExpr;
/**********************************************************************
* This routine transforms query trees with the following form:
@@ -73,8 +58,7 @@ static int inspectOrNode(Expr *expr);
*
* [email protected] 1998-08-31
*
- * Needs to better identify the signeture WHERE clause.
- * May want to also prune out duplicate where clauses.
+ * May want to also prune out duplicate terms.
**********************************************************************/
void
transformKeySetQuery(Query *origNode)
@@ -92,18 +76,20 @@ transformKeySetQuery(Query *origNode)
return;
/* Qualify single table query */
-
+ if (length(origNode->rtable) != 1)
+ return;
+
+ /* Sorry about the global, not worth passing around */
+ /* 9 expressions seems like a good number. More than 9 */
+ /* and it starts to slow down quite a bit */
+ TotalExpr = 0;
+ /*************************/
/* Qualify where clause */
- if ( ! inspectOrNode((Expr*)origNode->qual)) {
+ /*************************/
+ if ( ! inspectOrNode((Expr*)origNode->qual) || TotalExpr < 9)
return;
- }
/* Copy essential elements into a union node */
- /*
- elog(NOTICE, "OR_EXPR=%d, OP_EXPR=%d, AND_EXPR=%d", OR_EXPR, OP_EXPR, AND_EXPR);
- elog(NOTICE, "T_List=%d, T_Expr=%d, T_Var=%d, T_Const=%d", T_List, T_Expr, T_Var, T_Const);
- elog(NOTICE, "opType=%d", ((Expr*)origNode->qual)->opType);
- */
while (((Expr*)origNode->qual)->opType == OR_EXPR) {
Query *unionNode = makeNode(Query);
@@ -113,11 +99,6 @@ transformKeySetQuery(Query *origNode)
/* Pull up balance of tree */
origNode->qual = lfirst(((Expr*)origNode->qual)->args);
- /*
- elog(NOTICE, "origNode: opType=%d, nodeTag=%d", ((Expr*)origNode->qual)->opType, nodeTag(origNode->qual));
- elog(NOTICE, "unionNode: opType=%d, nodeTag=%d", ((Expr*)unionNode->qual)->opType, nodeTag(unionNode->qual));
- */
-
unionNode->commandType = origNode->commandType;
unionNode->resultRelation = origNode->resultRelation;
unionNode->isPortal = origNode->isPortal;
@@ -139,9 +120,14 @@ transformKeySetQuery(Query *origNode)
static int
+/**********************************************************************
+ * Checks for 1 or more OR terms w/ 1 or more AND terms.
+ * AND terms must be equal in size.
+ * Returns the number of each AND term.
+ **********************************************************************/
inspectOrNode(Expr *expr)
{
- int fr = 0, sr = 0;
+ int rc;
Expr *firstExpr, *secondExpr;
if ( ! (expr && nodeTag(expr) == T_Expr && expr->opType == OR_EXPR))
@@ -152,27 +138,35 @@ inspectOrNode(Expr *expr)
if (nodeTag(firstExpr) != T_Expr || nodeTag(secondExpr) != T_Expr)
return 0;
- if (firstExpr->opType == OR_EXPR)
- fr = inspectOrNode(firstExpr);
- else if (firstExpr->opType == OP_EXPR) /* Need to make sure it is last */
- fr = inspectOpNode(firstExpr);
- else if (firstExpr->opType == AND_EXPR) /* Need to make sure it is last */
- fr = inspectAndNode(firstExpr);
-
+ if (firstExpr->opType == OR_EXPR && secondExpr->opType == AND_EXPR)
+ {
+ if ((rc = inspectOrNode(firstExpr)) == 0)
+ return 0;
- if (secondExpr->opType == AND_EXPR)
- sr = inspectAndNode(secondExpr);
- else if (secondExpr->opType == OP_EXPR)
- sr = inspectOpNode(secondExpr);
+ return (rc == inspectAndNode(secondExpr)) ? rc : 0;
+ }
+ else if (firstExpr->opType == AND_EXPR && secondExpr->opType == AND_EXPR)
+ {
+ if ((rc = inspectAndNode(firstExpr)) == 0)
+ return 0;
+
+ return (rc == inspectAndNode(secondExpr)) ? rc : 0;
- return (fr && sr);
+ }
+
+ return 0;
}
static int
+/**********************************************************************
+ * Check for one or more AND terms. Each sub-term must be a T_Const
+ * T_Var expression.
+ * Returns the number of AND terms.
+ **********************************************************************/
inspectAndNode(Expr *expr)
{
- int fr = 0, sr = 0;
+ int rc;
Expr *firstExpr, *secondExpr;
if ( ! (expr && nodeTag(expr) == T_Expr && expr->opType == AND_EXPR))
@@ -183,15 +177,19 @@ inspectAndNode(Expr *expr)
if (nodeTag(firstExpr) != T_Expr || nodeTag(secondExpr) != T_Expr)
return 0;
- if (firstExpr->opType == AND_EXPR)
- fr = inspectAndNode(firstExpr);
- else if (firstExpr->opType == OP_EXPR)
- fr = inspectOpNode(firstExpr);
+ if (firstExpr->opType == AND_EXPR &&
+ secondExpr->opType == OP_EXPR && inspectOpNode(secondExpr))
+ {
+ rc = inspectAndNode(firstExpr);
+ return ((rc) ? (rc + 1) : 0); /* Add up the AND nodes */
+ }
+ else if (firstExpr->opType == OP_EXPR && inspectOpNode(firstExpr) &&
+ secondExpr->opType == OP_EXPR && inspectOpNode(secondExpr))
+ {
+ return 1;
+ }
- if (secondExpr->opType == OP_EXPR)
- sr = inspectOpNode(secondExpr);
-
- return (fr && sr);
+ return 0;
}
@@ -205,7 +203,9 @@ inspectOpNode(Expr *expr)
Expr *firstExpr, *secondExpr;
if (nodeTag(expr) != T_Expr || expr->opType != OP_EXPR)
- return 0;
+ return FALSE;
+
+ TotalExpr++;
firstExpr = lfirst(expr->args);
secondExpr = lsecond(expr->args);