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Create hooks to let a loadable plugin monitor (or even replace) the planner
and/or create plans for hypothetical situations; in particular, investigate plans that would be generated using hypothetical indexes. This is a heavily-rewritten version of the hooks proposed by Gurjeet Singh for his Index Advisor project. In this formulation, the index advisor can be entirely a loadable module instead of requiring a significant part to be in the core backend, and plans can be generated for hypothetical indexes without requiring the creation and rolling-back of system catalog entries. The index advisor patch as-submitted is not compatible with these hooks, but it needs significant work anyway due to other 8.2-to-8.3 planner changes. With these hooks in the core backend, development of the advisor can proceed as a pgfoundry project.
This commit is contained in:
Tom Lane
parent
ce5b24abed
commit
604ffd280b
@ -7,7 +7,7 @@
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* Portions Copyright (c) 1994-5, Regents of the University of California
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.163 2007/05/04 21:29:52 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.164 2007/05/25 17:54:24 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -33,6 +33,12 @@
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#include "utils/tuplesort.h"
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/* Hook for plugins to get control in ExplainOneQuery() */
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ExplainOneQuery_hook_type ExplainOneQuery_hook = NULL;
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/* Hook for plugins to get control in explain_get_index_name() */
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explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
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typedef struct ExplainState
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{
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/* options */
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@ -61,6 +67,8 @@ static void show_sort_keys(Plan *sortplan, int nkeys, AttrNumber *keycols,
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StringInfo str, int indent, ExplainState *es);
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static void show_sort_info(SortState *sortstate,
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StringInfo str, int indent, ExplainState *es);
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static const char *explain_get_index_name(Oid indexId);
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/*
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* ExplainQuery -
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@ -140,9 +148,6 @@ static void
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ExplainOneQuery(Query *query, ExplainStmt *stmt, const char *queryString,
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ParamListInfo params, TupOutputState *tstate)
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{
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PlannedStmt *plan;
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QueryDesc *queryDesc;
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/* planner will not cope with utility statements */
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if (query->commandType == CMD_UTILITY)
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{
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@ -151,25 +156,19 @@ ExplainOneQuery(Query *query, ExplainStmt *stmt, const char *queryString,
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return;
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}
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/* plan the query */
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plan = planner(query, 0, params);
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/* if an advisor plugin is present, let it manage things */
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if (ExplainOneQuery_hook)
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(*ExplainOneQuery_hook) (query, stmt, queryString, params, tstate);
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else
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{
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PlannedStmt *plan;
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/*
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* Update snapshot command ID to ensure this query sees results of any
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* previously executed queries. (It's a bit cheesy to modify
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* ActiveSnapshot without making a copy, but for the limited ways in which
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* EXPLAIN can be invoked, I think it's OK, because the active snapshot
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* shouldn't be shared with anything else anyway.)
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*/
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ActiveSnapshot->curcid = GetCurrentCommandId();
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/* plan the query */
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plan = planner(query, 0, params);
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/* Create a QueryDesc requesting no output */
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queryDesc = CreateQueryDesc(plan,
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ActiveSnapshot, InvalidSnapshot,
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None_Receiver, params,
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stmt->analyze);
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ExplainOnePlan(queryDesc, stmt, tstate);
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/* run it (if needed) and produce output */
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ExplainOnePlan(plan, params, stmt, tstate);
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}
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}
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/*
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@ -210,20 +209,35 @@ ExplainOneUtility(Node *utilityStmt, ExplainStmt *stmt,
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* not running the query. No cursor will be created, however.
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*
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* This is exported because it's called back from prepare.c in the
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* EXPLAIN EXECUTE case
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*
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* Note: the passed-in QueryDesc is freed when we're done with it
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* EXPLAIN EXECUTE case, and because an index advisor plugin would need
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* to call it.
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*/
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void
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ExplainOnePlan(QueryDesc *queryDesc, ExplainStmt *stmt,
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TupOutputState *tstate)
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ExplainOnePlan(PlannedStmt *plannedstmt, ParamListInfo params,
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ExplainStmt *stmt, TupOutputState *tstate)
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{
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QueryDesc *queryDesc;
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instr_time starttime;
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double totaltime = 0;
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ExplainState *es;
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StringInfoData buf;
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int eflags;
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/*
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* Update snapshot command ID to ensure this query sees results of any
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* previously executed queries. (It's a bit cheesy to modify
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* ActiveSnapshot without making a copy, but for the limited ways in which
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* EXPLAIN can be invoked, I think it's OK, because the active snapshot
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* shouldn't be shared with anything else anyway.)
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*/
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ActiveSnapshot->curcid = GetCurrentCommandId();
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/* Create a QueryDesc requesting no output */
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queryDesc = CreateQueryDesc(plannedstmt,
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ActiveSnapshot, InvalidSnapshot,
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None_Receiver, params,
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stmt->analyze);
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INSTR_TIME_SET_CURRENT(starttime);
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/* If analyzing, we need to cope with queued triggers */
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@ -592,7 +606,7 @@ explain_outNode(StringInfo str,
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if (ScanDirectionIsBackward(((IndexScan *) plan)->indexorderdir))
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appendStringInfoString(str, " Backward");
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appendStringInfo(str, " using %s",
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quote_identifier(get_rel_name(((IndexScan *) plan)->indexid)));
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explain_get_index_name(((IndexScan *) plan)->indexid));
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/* FALL THRU */
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case T_SeqScan:
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case T_BitmapHeapScan:
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@ -618,7 +632,7 @@ explain_outNode(StringInfo str,
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break;
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case T_BitmapIndexScan:
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appendStringInfo(str, " on %s",
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quote_identifier(get_rel_name(((BitmapIndexScan *) plan)->indexid)));
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explain_get_index_name(((BitmapIndexScan *) plan)->indexid));
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break;
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case T_SubqueryScan:
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if (((Scan *) plan)->scanrelid > 0)
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@ -1150,3 +1164,29 @@ show_sort_info(SortState *sortstate,
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pfree(sortinfo);
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}
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}
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/*
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* Fetch the name of an index in an EXPLAIN
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*
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* We allow plugins to get control here so that plans involving hypothetical
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* indexes can be explained.
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*/
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static const char *
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explain_get_index_name(Oid indexId)
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{
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const char *result;
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if (explain_get_index_name_hook)
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result = (*explain_get_index_name_hook) (indexId);
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else
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result = NULL;
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if (result == NULL)
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{
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/* default behavior: look in the catalogs and quote it */
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result = get_rel_name(indexId);
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if (result == NULL)
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elog(ERROR, "cache lookup failed for index %u", indexId);
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result = quote_identifier(result);
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}
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return result;
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}
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@ -10,7 +10,7 @@
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* Copyright (c) 2002-2007, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.75 2007/04/27 22:05:47 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.76 2007/05/25 17:54:25 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -678,8 +678,6 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, ExplainStmt *stmt,
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if (IsA(pstmt, PlannedStmt))
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{
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QueryDesc *qdesc;
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if (execstmt->into)
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{
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if (pstmt->commandType != CMD_SELECT ||
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@ -694,22 +692,7 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, ExplainStmt *stmt,
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pstmt->intoClause = execstmt->into;
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}
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/*
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* Update snapshot command ID to ensure this query sees results of
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* any previously executed queries. (It's a bit cheesy to modify
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* ActiveSnapshot without making a copy, but for the limited ways
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* in which EXPLAIN can be invoked, I think it's OK, because the
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* active snapshot shouldn't be shared with anything else anyway.)
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*/
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ActiveSnapshot->curcid = GetCurrentCommandId();
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/* Create a QueryDesc requesting no output */
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qdesc = CreateQueryDesc(pstmt,
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ActiveSnapshot, InvalidSnapshot,
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None_Receiver,
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paramLI, stmt->analyze);
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ExplainOnePlan(qdesc, stmt, tstate);
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ExplainOnePlan(pstmt, paramLI, stmt, tstate);
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}
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else
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{
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.22 2007/01/05 22:19:28 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.23 2007/05/25 17:54:25 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -198,10 +198,12 @@ ExecEndBitmapIndexScan(BitmapIndexScanState *node)
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#endif
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/*
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* close the index relation
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* close the index relation (no-op if we didn't open it)
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*/
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index_endscan(indexScanDesc);
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index_close(indexRelationDesc, NoLock);
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if (indexScanDesc)
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index_endscan(indexScanDesc);
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if (indexRelationDesc)
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index_close(indexRelationDesc, NoLock);
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}
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/* ----------------------------------------------------------------
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@ -256,6 +258,14 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate, int eflags)
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indexstate->ss.ss_currentRelation = NULL;
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indexstate->ss.ss_currentScanDesc = NULL;
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/*
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* If we are just doing EXPLAIN (ie, aren't going to run the plan),
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* stop here. This allows an index-advisor plugin to EXPLAIN a plan
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* containing references to nonexistent indexes.
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*/
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if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
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return indexstate;
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/*
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* Open the index relation.
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*
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.121 2007/04/06 22:33:42 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/executor/nodeIndexscan.c,v 1.122 2007/05/25 17:54:25 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -415,10 +415,12 @@ ExecEndIndexScan(IndexScanState *node)
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ExecClearTuple(node->ss.ss_ScanTupleSlot);
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/*
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* close the index relation
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* close the index relation (no-op if we didn't open it)
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*/
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index_endscan(indexScanDesc);
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index_close(indexRelationDesc, NoLock);
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if (indexScanDesc)
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index_endscan(indexScanDesc);
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if (indexRelationDesc)
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index_close(indexRelationDesc, NoLock);
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/*
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* close the heap relation.
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@ -520,6 +522,14 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags)
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*/
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ExecAssignScanType(&indexstate->ss, RelationGetDescr(currentRelation));
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/*
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* If we are just doing EXPLAIN (ie, aren't going to run the plan),
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* stop here. This allows an index-advisor plugin to EXPLAIN a plan
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* containing references to nonexistent indexes.
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*/
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if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
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return indexstate;
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/*
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* Open the index relation.
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*
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.219 2007/05/04 01:13:44 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.220 2007/05/25 17:54:25 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -42,6 +42,10 @@
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#include "utils/syscache.h"
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/* Hook for plugins to get control in planner() */
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planner_hook_type planner_hook = NULL;
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/* Expression kind codes for preprocess_expression */
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#define EXPRKIND_QUAL 0
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#define EXPRKIND_TARGET 1
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@ -79,9 +83,29 @@ static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist);
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*
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* Query optimizer entry point
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*
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* To support loadable plugins that monitor or modify planner behavior,
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* we provide a hook variable that lets a plugin get control before and
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* after the standard planning process. The plugin would normally call
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* standard_planner().
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*
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* Note to plugin authors: standard_planner() scribbles on its Query input,
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* so you'd better copy that data structure if you want to plan more than once.
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*
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*****************************************************************************/
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PlannedStmt *
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planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
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{
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PlannedStmt *result;
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if (planner_hook)
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result = (*planner_hook) (parse, cursorOptions, boundParams);
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else
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result = standard_planner(parse, cursorOptions, boundParams);
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return result;
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}
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PlannedStmt *
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standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
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{
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PlannedStmt *result;
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PlannerGlobal *glob;
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@ -9,7 +9,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.134 2007/04/21 21:01:45 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/optimizer/util/plancat.c,v 1.135 2007/05/25 17:54:25 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -40,6 +40,9 @@
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/* GUC parameter */
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bool constraint_exclusion = false;
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/* Hook for plugins to get control in get_relation_info() */
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get_relation_info_hook_type get_relation_info_hook = NULL;
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static void estimate_rel_size(Relation rel, int32 *attr_widths,
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BlockNumber *pages, double *tuples);
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@ -279,6 +282,14 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
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rel->indexlist = indexinfos;
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heap_close(relation, NoLock);
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/*
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* Allow a plugin to editorialize on the info we obtained from the
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* catalogs. Actions might include altering the assumed relation size,
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* removing an index, or adding a hypothetical index to the indexlist.
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*/
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if (get_relation_info_hook)
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(*get_relation_info_hook) (root, relationObjectId, inhparent, rel);
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}
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/*
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@ -6,7 +6,7 @@
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994-5, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/commands/explain.h,v 1.30 2007/03/13 00:33:43 tgl Exp $
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* $PostgreSQL: pgsql/src/include/commands/explain.h,v 1.31 2007/05/25 17:54:25 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -15,6 +15,18 @@
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#include "executor/executor.h"
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/* Hook for plugins to get control in ExplainOneQuery() */
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typedef void (*ExplainOneQuery_hook_type) (Query *query,
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ExplainStmt *stmt,
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const char *queryString,
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ParamListInfo params,
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TupOutputState *tstate);
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extern DLLIMPORT ExplainOneQuery_hook_type ExplainOneQuery_hook;
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/* Hook for plugins to get control in explain_get_index_name() */
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typedef const char * (*explain_get_index_name_hook_type) (Oid indexId);
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extern DLLIMPORT explain_get_index_name_hook_type explain_get_index_name_hook;
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extern void ExplainQuery(ExplainStmt *stmt, const char *queryString,
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ParamListInfo params, DestReceiver *dest);
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@ -26,7 +38,7 @@ extern void ExplainOneUtility(Node *utilityStmt, ExplainStmt *stmt,
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ParamListInfo params,
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TupOutputState *tstate);
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extern void ExplainOnePlan(QueryDesc *queryDesc, ExplainStmt *stmt,
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TupOutputState *tstate);
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extern void ExplainOnePlan(PlannedStmt *plannedstmt, ParamListInfo params,
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ExplainStmt *stmt, TupOutputState *tstate);
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#endif /* EXPLAIN_H */
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/optimizer/plancat.h,v 1.43 2007/01/05 22:19:56 momjian Exp $
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* $PostgreSQL: pgsql/src/include/optimizer/plancat.h,v 1.44 2007/05/25 17:54:25 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -16,6 +16,13 @@
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#include "nodes/relation.h"
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/* Hook for plugins to get control in get_relation_info() */
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typedef void (*get_relation_info_hook_type) (PlannerInfo *root,
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Oid relationObjectId,
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bool inhparent,
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RelOptInfo *rel);
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extern DLLIMPORT get_relation_info_hook_type get_relation_info_hook;
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extern void get_relation_info(PlannerInfo *root, Oid relationObjectId,
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bool inhparent, RelOptInfo *rel);
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/optimizer/planner.h,v 1.39 2007/04/16 01:14:58 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/include/optimizer/planner.h,v 1.40 2007/05/25 17:54:25 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -18,8 +18,17 @@
|
||||
#include "nodes/relation.h"
|
||||
|
||||
|
||||
/* Hook for plugins to get control in planner() */
|
||||
typedef PlannedStmt * (*planner_hook_type) (Query *parse,
|
||||
int cursorOptions,
|
||||
ParamListInfo boundParams);
|
||||
extern DLLIMPORT planner_hook_type planner_hook;
|
||||
|
||||
|
||||
extern PlannedStmt *planner(Query *parse, int cursorOptions,
|
||||
ParamListInfo boundParams);
|
||||
extern PlannedStmt *standard_planner(Query *parse, int cursorOptions,
|
||||
ParamListInfo boundParams);
|
||||
extern Plan *subquery_planner(PlannerGlobal *glob, Query *parse,
|
||||
Index level, double tuple_fraction,
|
||||
PlannerInfo **subroot);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user