Oops missing file.
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Bruce Momjian
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9d8d647146
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/*-------------------------------------------------------------------------
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*
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* prepkeyset.c--
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* Special preperation for keyset queries.
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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*-------------------------------------------------------------------------
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*/
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#include <stdio.h>
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#include <string.h>
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#include "postgres.h"
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#include "nodes/pg_list.h"
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#include "nodes/parsenodes.h"
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#include "utils/elog.h"
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#include "nodes/nodes.h"
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#include "nodes/execnodes.h"
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#include "nodes/plannodes.h"
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#include "nodes/primnodes.h"
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#include "nodes/relation.h"
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#include "catalog/pg_type.h"
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#include "lib/stringinfo.h"
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#include "optimizer/planmain.h"
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/*
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* Node_Copy--
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* a macro to simplify calling of copyObject on the specified field
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*/
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#define Node_Copy(from, newnode, field) newnode->field = copyObject(from->field)
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/***** DEBUG stuff
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#define TABS {int i; printf("\n"); for (i = 0; i<level; i++) printf("\t"); }
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static int level = 0;
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******/
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bool _use_keyset_query_optimizer = FALSE;
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static int inspectOpNode(Expr *expr);
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static int inspectAndNode(Expr *expr);
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static int inspectOrNode(Expr *expr);
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/**********************************************************************
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* This routine transforms query trees with the following form:
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* SELECT a,b, ... FROM one_table WHERE
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* (v1 = const1 AND v2 = const2 [ vn = constn ]) OR
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* (v1 = const3 AND v2 = const4 [ vn = constn ]) OR
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* (v1 = const5 AND v2 = const6 [ vn = constn ]) OR
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* ...
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* [(v1 = constn AND v2 = constn [ vn = constn ])]
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*
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* into
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*
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* SELECT a,b, ... FROM one_table WHERE
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* (v1 = const1 AND v2 = const2 [ vn = constn ]) UNION
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* SELECT a,b, ... FROM one_table WHERE
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* (v1 = const3 AND v2 = const4 [ vn = constn ]) UNION
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* SELECT a,b, ... FROM one_table WHERE
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* (v1 = const5 AND v2 = const6 [ vn = constn ]) UNION
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* ...
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* SELECT a,b, ... FROM one_table WHERE
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* [(v1 = constn AND v2 = constn [ vn = constn ])]
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*
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*
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* To qualify for transformation the query must not be a sub select,
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* a HAVING, or a GROUP BY. It must be a single table and have KSQO
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* set to 'on'.
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*
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* The primary use of this transformation is to avoid the exponrntial
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* memory consumption of cnfify() and to make use of index access
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* methods.
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*
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* daveh@insightdist.com 1998-08-31
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*
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* Needs to better identify the signeture WHERE clause.
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* May want to also prune out duplicate where clauses.
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**********************************************************************/
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void
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transformKeySetQuery(Query *origNode)
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{
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/* Qualify as a key set query candidate */
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if (_use_keyset_query_optimizer == FALSE ||
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origNode->groupClause ||
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origNode->havingQual ||
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origNode->hasAggs ||
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origNode->utilityStmt ||
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origNode->unionClause ||
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origNode->unionall ||
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origNode->hasSubLinks ||
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origNode->commandType != CMD_SELECT)
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return;
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/* Qualify single table query */
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/* Qualify where clause */
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if ( ! inspectOrNode((Expr*)origNode->qual)) {
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return;
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}
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/* Copy essential elements into a union node */
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/*
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elog(NOTICE, "OR_EXPR=%d, OP_EXPR=%d, AND_EXPR=%d", OR_EXPR, OP_EXPR, AND_EXPR);
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elog(NOTICE, "T_List=%d, T_Expr=%d, T_Var=%d, T_Const=%d", T_List, T_Expr, T_Var, T_Const);
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elog(NOTICE, "opType=%d", ((Expr*)origNode->qual)->opType);
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*/
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while (((Expr*)origNode->qual)->opType == OR_EXPR) {
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Query *unionNode = makeNode(Query);
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/* Pull up Expr = */
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unionNode->qual = lsecond(((Expr*)origNode->qual)->args);
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/* Pull up balance of tree */
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origNode->qual = lfirst(((Expr*)origNode->qual)->args);
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/*
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elog(NOTICE, "origNode: opType=%d, nodeTag=%d", ((Expr*)origNode->qual)->opType, nodeTag(origNode->qual));
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elog(NOTICE, "unionNode: opType=%d, nodeTag=%d", ((Expr*)unionNode->qual)->opType, nodeTag(unionNode->qual));
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*/
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unionNode->commandType = origNode->commandType;
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unionNode->resultRelation = origNode->resultRelation;
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unionNode->isPortal = origNode->isPortal;
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unionNode->isBinary = origNode->isBinary;
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if (origNode->uniqueFlag)
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unionNode->uniqueFlag = pstrdup(origNode->uniqueFlag);
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Node_Copy(origNode, unionNode, sortClause);
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Node_Copy(origNode, unionNode, rtable);
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Node_Copy(origNode, unionNode, targetList);
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origNode->unionClause = lappend(origNode->unionClause, unionNode);
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}
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return;
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}
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static int
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inspectOrNode(Expr *expr)
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{
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int fr = 0, sr = 0;
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Expr *firstExpr, *secondExpr;
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if ( ! (expr && nodeTag(expr) == T_Expr && expr->opType == OR_EXPR))
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return 0;
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firstExpr = lfirst(expr->args);
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secondExpr = lsecond(expr->args);
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if (nodeTag(firstExpr) != T_Expr || nodeTag(secondExpr) != T_Expr)
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return 0;
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if (firstExpr->opType == OR_EXPR)
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fr = inspectOrNode(firstExpr);
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else if (firstExpr->opType == OP_EXPR) /* Need to make sure it is last */
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fr = inspectOpNode(firstExpr);
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else if (firstExpr->opType == AND_EXPR) /* Need to make sure it is last */
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fr = inspectAndNode(firstExpr);
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if (secondExpr->opType == AND_EXPR)
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sr = inspectAndNode(secondExpr);
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else if (secondExpr->opType == OP_EXPR)
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sr = inspectOpNode(secondExpr);
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return (fr && sr);
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}
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static int
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inspectAndNode(Expr *expr)
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{
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int fr = 0, sr = 0;
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Expr *firstExpr, *secondExpr;
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if ( ! (expr && nodeTag(expr) == T_Expr && expr->opType == AND_EXPR))
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return 0;
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firstExpr = lfirst(expr->args);
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secondExpr = lsecond(expr->args);
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if (nodeTag(firstExpr) != T_Expr || nodeTag(secondExpr) != T_Expr)
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return 0;
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if (firstExpr->opType == AND_EXPR)
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fr = inspectAndNode(firstExpr);
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else if (firstExpr->opType == OP_EXPR)
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fr = inspectOpNode(firstExpr);
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if (secondExpr->opType == OP_EXPR)
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sr = inspectOpNode(secondExpr);
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return (fr && sr);
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}
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static int
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/******************************************************************
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* Return TRUE if T_Var = T_Const, else FALSE
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* Actually it does not test for =. Need to do this!
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******************************************************************/
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inspectOpNode(Expr *expr)
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{
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Expr *firstExpr, *secondExpr;
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if (nodeTag(expr) != T_Expr || expr->opType != OP_EXPR)
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return 0;
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firstExpr = lfirst(expr->args);
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secondExpr = lsecond(expr->args);
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return (firstExpr && secondExpr && nodeTag(firstExpr) == T_Var && nodeTag(secondExpr) == T_Const);
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}
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