1832 lines
57 KiB
C
1832 lines
57 KiB
C
/*-------------------------------------------------------------------------
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*
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* plancache.c
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* Plan cache management.
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*
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* The plan cache manager has two principal responsibilities: deciding when
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* to use a generic plan versus a custom (parameter-value-specific) plan,
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* and tracking whether cached plans need to be invalidated because of schema
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* changes in the objects they depend on.
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*
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* The logic for choosing generic or custom plans is in choose_custom_plan,
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* which see for comments.
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*
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* Cache invalidation is driven off sinval events. Any CachedPlanSource
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* that matches the event is marked invalid, as is its generic CachedPlan
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* if it has one. When (and if) the next demand for a cached plan occurs,
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* parse analysis and rewrite is repeated to build a new valid query tree,
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* and then planning is performed as normal. We also force re-analysis and
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* re-planning if the active search_path is different from the previous time.
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*
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* Note that if the sinval was a result of user DDL actions, parse analysis
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* could throw an error, for example if a column referenced by the query is
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* no longer present. Another possibility is for the query's output tupdesc
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* to change (for instance "SELECT *" might expand differently than before).
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* The creator of a cached plan can specify whether it is allowable for the
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* query to change output tupdesc on replan --- if so, it's up to the
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* caller to notice changes and cope with them.
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*
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* Currently, we track exactly the dependencies of plans on relations and
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* user-defined functions. On relcache invalidation events or pg_proc
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* syscache invalidation events, we invalidate just those plans that depend
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* on the particular object being modified. (Note: this scheme assumes
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* that any table modification that requires replanning will generate a
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* relcache inval event.) We also watch for inval events on certain other
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* system catalogs, such as pg_namespace; but for them, our response is
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* just to invalidate all plans. We expect updates on those catalogs to
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* be infrequent enough that more-detailed tracking is not worth the effort.
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*
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*
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* Portions Copyright (c) 1996-2013, 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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* IDENTIFICATION
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* src/backend/utils/cache/plancache.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <limits.h>
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#include "access/transam.h"
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#include "catalog/namespace.h"
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#include "executor/executor.h"
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#include "executor/spi.h"
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#include "nodes/nodeFuncs.h"
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#include "optimizer/planmain.h"
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#include "optimizer/prep.h"
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#include "parser/analyze.h"
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#include "parser/parsetree.h"
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#include "storage/lmgr.h"
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#include "tcop/pquery.h"
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#include "tcop/utility.h"
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#include "utils/inval.h"
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#include "utils/memutils.h"
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#include "utils/resowner_private.h"
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#include "utils/snapmgr.h"
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#include "utils/syscache.h"
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/*
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* We must skip "overhead" operations that involve database access when the
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* cached plan's subject statement is a transaction control command.
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*/
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#define IsTransactionStmtPlan(plansource) \
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((plansource)->raw_parse_tree && \
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IsA((plansource)->raw_parse_tree, TransactionStmt))
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/*
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* This is the head of the backend's list of "saved" CachedPlanSources (i.e.,
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* those that are in long-lived storage and are examined for sinval events).
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* We thread the structs manually instead of using List cells so that we can
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* guarantee to save a CachedPlanSource without error.
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*/
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static CachedPlanSource *first_saved_plan = NULL;
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static void ReleaseGenericPlan(CachedPlanSource *plansource);
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static List *RevalidateCachedQuery(CachedPlanSource *plansource);
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static bool CheckCachedPlan(CachedPlanSource *plansource);
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static CachedPlan *BuildCachedPlan(CachedPlanSource *plansource, List *qlist,
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ParamListInfo boundParams);
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static bool choose_custom_plan(CachedPlanSource *plansource,
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ParamListInfo boundParams);
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static double cached_plan_cost(CachedPlan *plan);
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static void AcquireExecutorLocks(List *stmt_list, bool acquire);
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static void AcquirePlannerLocks(List *stmt_list, bool acquire);
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static void ScanQueryForLocks(Query *parsetree, bool acquire);
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static bool ScanQueryWalker(Node *node, bool *acquire);
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static bool plan_list_is_transient(List *stmt_list);
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static TupleDesc PlanCacheComputeResultDesc(List *stmt_list);
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static void PlanCacheRelCallback(Datum arg, Oid relid);
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static void PlanCacheFuncCallback(Datum arg, int cacheid, uint32 hashvalue);
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static void PlanCacheSysCallback(Datum arg, int cacheid, uint32 hashvalue);
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/*
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* InitPlanCache: initialize module during InitPostgres.
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*
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* All we need to do is hook into inval.c's callback lists.
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*/
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void
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InitPlanCache(void)
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{
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CacheRegisterRelcacheCallback(PlanCacheRelCallback, (Datum) 0);
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CacheRegisterSyscacheCallback(PROCOID, PlanCacheFuncCallback, (Datum) 0);
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CacheRegisterSyscacheCallback(NAMESPACEOID, PlanCacheSysCallback, (Datum) 0);
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CacheRegisterSyscacheCallback(OPEROID, PlanCacheSysCallback, (Datum) 0);
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CacheRegisterSyscacheCallback(AMOPOPID, PlanCacheSysCallback, (Datum) 0);
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}
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/*
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* CreateCachedPlan: initially create a plan cache entry.
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*
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* Creation of a cached plan is divided into two steps, CreateCachedPlan and
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* CompleteCachedPlan. CreateCachedPlan should be called after running the
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* query through raw_parser, but before doing parse analysis and rewrite;
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* CompleteCachedPlan is called after that. The reason for this arrangement
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* is that it can save one round of copying of the raw parse tree, since
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* the parser will normally scribble on the raw parse tree. Callers would
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* otherwise need to make an extra copy of the parse tree to ensure they
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* still had a clean copy to present at plan cache creation time.
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*
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* All arguments presented to CreateCachedPlan are copied into a memory
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* context created as a child of the call-time CurrentMemoryContext, which
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* should be a reasonably short-lived working context that will go away in
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* event of an error. This ensures that the cached plan data structure will
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* likewise disappear if an error occurs before we have fully constructed it.
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* Once constructed, the cached plan can be made longer-lived, if needed,
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* by calling SaveCachedPlan.
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*
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* raw_parse_tree: output of raw_parser()
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* query_string: original query text
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* commandTag: compile-time-constant tag for query, or NULL if empty query
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*/
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CachedPlanSource *
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CreateCachedPlan(Node *raw_parse_tree,
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const char *query_string,
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const char *commandTag)
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{
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CachedPlanSource *plansource;
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MemoryContext source_context;
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MemoryContext oldcxt;
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Assert(query_string != NULL); /* required as of 8.4 */
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/*
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* Make a dedicated memory context for the CachedPlanSource and its
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* permanent subsidiary data. It's probably not going to be large, but
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* just in case, use the default maxsize parameter. Initially it's a
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* child of the caller's context (which we assume to be transient), so
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* that it will be cleaned up on error.
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*/
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source_context = AllocSetContextCreate(CurrentMemoryContext,
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"CachedPlanSource",
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ALLOCSET_SMALL_MINSIZE,
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ALLOCSET_SMALL_INITSIZE,
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ALLOCSET_DEFAULT_MAXSIZE);
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/*
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* Create and fill the CachedPlanSource struct within the new context.
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* Most fields are just left empty for the moment.
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*/
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oldcxt = MemoryContextSwitchTo(source_context);
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plansource = (CachedPlanSource *) palloc0(sizeof(CachedPlanSource));
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plansource->magic = CACHEDPLANSOURCE_MAGIC;
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plansource->raw_parse_tree = copyObject(raw_parse_tree);
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plansource->query_string = pstrdup(query_string);
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plansource->commandTag = commandTag;
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plansource->param_types = NULL;
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plansource->num_params = 0;
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plansource->parserSetup = NULL;
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plansource->parserSetupArg = NULL;
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plansource->cursor_options = 0;
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plansource->fixed_result = false;
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plansource->resultDesc = NULL;
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plansource->context = source_context;
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plansource->query_list = NIL;
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plansource->relationOids = NIL;
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plansource->invalItems = NIL;
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plansource->search_path = NULL;
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plansource->query_context = NULL;
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plansource->gplan = NULL;
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plansource->is_oneshot = false;
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plansource->is_complete = false;
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plansource->is_saved = false;
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plansource->is_valid = false;
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plansource->generation = 0;
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plansource->next_saved = NULL;
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plansource->generic_cost = -1;
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plansource->total_custom_cost = 0;
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plansource->num_custom_plans = 0;
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MemoryContextSwitchTo(oldcxt);
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return plansource;
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}
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/*
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* CreateOneShotCachedPlan: initially create a one-shot plan cache entry.
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*
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* This variant of CreateCachedPlan creates a plan cache entry that is meant
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* to be used only once. No data copying occurs: all data structures remain
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* in the caller's memory context (which typically should get cleared after
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* completing execution). The CachedPlanSource struct itself is also created
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* in that context.
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*
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* A one-shot plan cannot be saved or copied, since we make no effort to
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* preserve the raw parse tree unmodified. There is also no support for
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* invalidation, so plan use must be completed in the current transaction,
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* and DDL that might invalidate the querytree_list must be avoided as well.
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*
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* raw_parse_tree: output of raw_parser()
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* query_string: original query text
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* commandTag: compile-time-constant tag for query, or NULL if empty query
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*/
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CachedPlanSource *
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CreateOneShotCachedPlan(Node *raw_parse_tree,
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const char *query_string,
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const char *commandTag)
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{
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CachedPlanSource *plansource;
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Assert(query_string != NULL); /* required as of 8.4 */
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/*
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* Create and fill the CachedPlanSource struct within the caller's memory
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* context. Most fields are just left empty for the moment.
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*/
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plansource = (CachedPlanSource *) palloc0(sizeof(CachedPlanSource));
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plansource->magic = CACHEDPLANSOURCE_MAGIC;
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plansource->raw_parse_tree = raw_parse_tree;
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plansource->query_string = query_string;
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plansource->commandTag = commandTag;
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plansource->param_types = NULL;
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plansource->num_params = 0;
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plansource->parserSetup = NULL;
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plansource->parserSetupArg = NULL;
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plansource->cursor_options = 0;
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plansource->fixed_result = false;
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plansource->resultDesc = NULL;
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plansource->context = CurrentMemoryContext;
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plansource->query_list = NIL;
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plansource->relationOids = NIL;
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plansource->invalItems = NIL;
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plansource->search_path = NULL;
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plansource->query_context = NULL;
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plansource->gplan = NULL;
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plansource->is_oneshot = true;
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plansource->is_complete = false;
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plansource->is_saved = false;
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plansource->is_valid = false;
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plansource->generation = 0;
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plansource->next_saved = NULL;
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plansource->generic_cost = -1;
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plansource->total_custom_cost = 0;
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plansource->num_custom_plans = 0;
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return plansource;
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}
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/*
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* CompleteCachedPlan: second step of creating a plan cache entry.
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*
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* Pass in the analyzed-and-rewritten form of the query, as well as the
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* required subsidiary data about parameters and such. All passed values will
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* be copied into the CachedPlanSource's memory, except as specified below.
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* After this is called, GetCachedPlan can be called to obtain a plan, and
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* optionally the CachedPlanSource can be saved using SaveCachedPlan.
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*
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* If querytree_context is not NULL, the querytree_list must be stored in that
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* context (but the other parameters need not be). The querytree_list is not
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* copied, rather the given context is kept as the initial query_context of
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* the CachedPlanSource. (It should have been created as a child of the
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* caller's working memory context, but it will now be reparented to belong
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* to the CachedPlanSource.) The querytree_context is normally the context in
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* which the caller did raw parsing and parse analysis. This approach saves
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* one tree copying step compared to passing NULL, but leaves lots of extra
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* cruft in the query_context, namely whatever extraneous stuff parse analysis
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* created, as well as whatever went unused from the raw parse tree. Using
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* this option is a space-for-time tradeoff that is appropriate if the
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* CachedPlanSource is not expected to survive long.
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*
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* plancache.c cannot know how to copy the data referenced by parserSetupArg,
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* and it would often be inappropriate to do so anyway. When using that
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* option, it is caller's responsibility that the referenced data remains
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* valid for as long as the CachedPlanSource exists.
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*
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* If the CachedPlanSource is a "oneshot" plan, then no querytree copying
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* occurs at all, and querytree_context is ignored; it is caller's
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* responsibility that the passed querytree_list is sufficiently long-lived.
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*
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* plansource: structure returned by CreateCachedPlan
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* querytree_list: analyzed-and-rewritten form of query (list of Query nodes)
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* querytree_context: memory context containing querytree_list,
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* or NULL to copy querytree_list into a fresh context
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* param_types: array of fixed parameter type OIDs, or NULL if none
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* num_params: number of fixed parameters
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* parserSetup: alternate method for handling query parameters
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* parserSetupArg: data to pass to parserSetup
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* cursor_options: options bitmask to pass to planner
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* fixed_result: TRUE to disallow future changes in query's result tupdesc
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*/
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void
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CompleteCachedPlan(CachedPlanSource *plansource,
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List *querytree_list,
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MemoryContext querytree_context,
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Oid *param_types,
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int num_params,
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ParserSetupHook parserSetup,
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void *parserSetupArg,
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int cursor_options,
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bool fixed_result)
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{
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MemoryContext source_context = plansource->context;
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MemoryContext oldcxt = CurrentMemoryContext;
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/* Assert caller is doing things in a sane order */
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Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
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Assert(!plansource->is_complete);
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/*
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* If caller supplied a querytree_context, reparent it underneath the
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* CachedPlanSource's context; otherwise, create a suitable context and
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* copy the querytree_list into it. But no data copying should be done
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* for one-shot plans; for those, assume the passed querytree_list is
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* sufficiently long-lived.
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*/
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if (plansource->is_oneshot)
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{
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querytree_context = CurrentMemoryContext;
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}
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else if (querytree_context != NULL)
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{
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MemoryContextSetParent(querytree_context, source_context);
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MemoryContextSwitchTo(querytree_context);
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}
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else
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{
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/* Again, it's a good bet the querytree_context can be small */
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querytree_context = AllocSetContextCreate(source_context,
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"CachedPlanQuery",
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ALLOCSET_SMALL_MINSIZE,
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ALLOCSET_SMALL_INITSIZE,
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ALLOCSET_DEFAULT_MAXSIZE);
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MemoryContextSwitchTo(querytree_context);
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querytree_list = (List *) copyObject(querytree_list);
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}
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plansource->query_context = querytree_context;
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plansource->query_list = querytree_list;
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if (!plansource->is_oneshot && !IsTransactionStmtPlan(plansource))
|
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{
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/*
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* Use the planner machinery to extract dependencies. Data is saved
|
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* in query_context. (We assume that not a lot of extra cruft is
|
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* created by this call.) We can skip this for one-shot plans, and
|
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* transaction control commands have no such dependencies anyway.
|
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*/
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extract_query_dependencies((Node *) querytree_list,
|
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&plansource->relationOids,
|
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&plansource->invalItems);
|
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|
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/*
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* Also save the current search_path in the query_context. (This
|
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* should not generate much extra cruft either, since almost certainly
|
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* the path is already valid.) Again, we don't really need this for
|
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* one-shot plans; and we *must* skip this for transaction control
|
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* commands, because this could result in catalog accesses.
|
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*/
|
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plansource->search_path = GetOverrideSearchPath(querytree_context);
|
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}
|
|
|
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/*
|
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* Save the final parameter types (or other parameter specification data)
|
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* into the source_context, as well as our other parameters. Also save
|
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* the result tuple descriptor.
|
|
*/
|
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MemoryContextSwitchTo(source_context);
|
|
|
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if (num_params > 0)
|
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{
|
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plansource->param_types = (Oid *) palloc(num_params * sizeof(Oid));
|
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memcpy(plansource->param_types, param_types, num_params * sizeof(Oid));
|
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}
|
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else
|
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plansource->param_types = NULL;
|
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plansource->num_params = num_params;
|
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plansource->parserSetup = parserSetup;
|
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plansource->parserSetupArg = parserSetupArg;
|
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plansource->cursor_options = cursor_options;
|
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plansource->fixed_result = fixed_result;
|
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plansource->resultDesc = PlanCacheComputeResultDesc(querytree_list);
|
|
|
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MemoryContextSwitchTo(oldcxt);
|
|
|
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plansource->is_complete = true;
|
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plansource->is_valid = true;
|
|
}
|
|
|
|
/*
|
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* SaveCachedPlan: save a cached plan permanently
|
|
*
|
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* This function moves the cached plan underneath CacheMemoryContext (making
|
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* it live for the life of the backend, unless explicitly dropped), and adds
|
|
* it to the list of cached plans that are checked for invalidation when an
|
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* sinval event occurs.
|
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*
|
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* This is guaranteed not to throw error, except for the caller-error case
|
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* of trying to save a one-shot plan. Callers typically depend on that
|
|
* since this is called just before or just after adding a pointer to the
|
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* CachedPlanSource to some permanent data structure of their own. Up until
|
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* this is done, a CachedPlanSource is just transient data that will go away
|
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* automatically on transaction abort.
|
|
*/
|
|
void
|
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SaveCachedPlan(CachedPlanSource *plansource)
|
|
{
|
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/* Assert caller is doing things in a sane order */
|
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Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
Assert(plansource->is_complete);
|
|
Assert(!plansource->is_saved);
|
|
|
|
/* This seems worth a real test, though */
|
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if (plansource->is_oneshot)
|
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elog(ERROR, "cannot save one-shot cached plan");
|
|
|
|
/*
|
|
* In typical use, this function would be called before generating any
|
|
* plans from the CachedPlanSource. If there is a generic plan, moving it
|
|
* into CacheMemoryContext would be pretty risky since it's unclear
|
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* whether the caller has taken suitable care with making references
|
|
* long-lived. Best thing to do seems to be to discard the plan.
|
|
*/
|
|
ReleaseGenericPlan(plansource);
|
|
|
|
/*
|
|
* Reparent the source memory context under CacheMemoryContext so that it
|
|
* will live indefinitely. The query_context follows along since it's
|
|
* already a child of the other one.
|
|
*/
|
|
MemoryContextSetParent(plansource->context, CacheMemoryContext);
|
|
|
|
/*
|
|
* Add the entry to the global list of cached plans.
|
|
*/
|
|
plansource->next_saved = first_saved_plan;
|
|
first_saved_plan = plansource;
|
|
|
|
plansource->is_saved = true;
|
|
}
|
|
|
|
/*
|
|
* DropCachedPlan: destroy a cached plan.
|
|
*
|
|
* Actually this only destroys the CachedPlanSource: any referenced CachedPlan
|
|
* is released, but not destroyed until its refcount goes to zero. That
|
|
* handles the situation where DropCachedPlan is called while the plan is
|
|
* still in use.
|
|
*/
|
|
void
|
|
DropCachedPlan(CachedPlanSource *plansource)
|
|
{
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
|
|
/* If it's been saved, remove it from the list */
|
|
if (plansource->is_saved)
|
|
{
|
|
if (first_saved_plan == plansource)
|
|
first_saved_plan = plansource->next_saved;
|
|
else
|
|
{
|
|
CachedPlanSource *psrc;
|
|
|
|
for (psrc = first_saved_plan; psrc; psrc = psrc->next_saved)
|
|
{
|
|
if (psrc->next_saved == plansource)
|
|
{
|
|
psrc->next_saved = plansource->next_saved;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
plansource->is_saved = false;
|
|
}
|
|
|
|
/* Decrement generic CachePlan's refcount and drop if no longer needed */
|
|
ReleaseGenericPlan(plansource);
|
|
|
|
/* Mark it no longer valid */
|
|
plansource->magic = 0;
|
|
|
|
/*
|
|
* Remove the CachedPlanSource and all subsidiary data (including the
|
|
* query_context if any). But if it's a one-shot we can't free anything.
|
|
*/
|
|
if (!plansource->is_oneshot)
|
|
MemoryContextDelete(plansource->context);
|
|
}
|
|
|
|
/*
|
|
* ReleaseGenericPlan: release a CachedPlanSource's generic plan, if any.
|
|
*/
|
|
static void
|
|
ReleaseGenericPlan(CachedPlanSource *plansource)
|
|
{
|
|
/* Be paranoid about the possibility that ReleaseCachedPlan fails */
|
|
if (plansource->gplan)
|
|
{
|
|
CachedPlan *plan = plansource->gplan;
|
|
|
|
Assert(plan->magic == CACHEDPLAN_MAGIC);
|
|
plansource->gplan = NULL;
|
|
ReleaseCachedPlan(plan, false);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* RevalidateCachedQuery: ensure validity of analyzed-and-rewritten query tree.
|
|
*
|
|
* What we do here is re-acquire locks and redo parse analysis if necessary.
|
|
* On return, the query_list is valid and we have sufficient locks to begin
|
|
* planning.
|
|
*
|
|
* If any parse analysis activity is required, the caller's memory context is
|
|
* used for that work.
|
|
*
|
|
* The result value is the transient analyzed-and-rewritten query tree if we
|
|
* had to do re-analysis, and NIL otherwise. (This is returned just to save
|
|
* a tree copying step in a subsequent BuildCachedPlan call.)
|
|
*/
|
|
static List *
|
|
RevalidateCachedQuery(CachedPlanSource *plansource)
|
|
{
|
|
bool snapshot_set;
|
|
Node *rawtree;
|
|
List *tlist; /* transient query-tree list */
|
|
List *qlist; /* permanent query-tree list */
|
|
TupleDesc resultDesc;
|
|
MemoryContext querytree_context;
|
|
MemoryContext oldcxt;
|
|
|
|
/*
|
|
* For one-shot plans, we do not support revalidation checking; it's
|
|
* assumed the query is parsed, planned, and executed in one transaction,
|
|
* so that no lock re-acquisition is necessary. Also, there is never any
|
|
* need to revalidate plans for transaction control commands (and we
|
|
* mustn't risk any catalog accesses when handling those).
|
|
*/
|
|
if (plansource->is_oneshot || IsTransactionStmtPlan(plansource))
|
|
{
|
|
Assert(plansource->is_valid);
|
|
return NIL;
|
|
}
|
|
|
|
/*
|
|
* If the query is currently valid, we should have a saved search_path ---
|
|
* check to see if that matches the current environment. If not, we want
|
|
* to force replan.
|
|
*/
|
|
if (plansource->is_valid)
|
|
{
|
|
Assert(plansource->search_path != NULL);
|
|
if (!OverrideSearchPathMatchesCurrent(plansource->search_path))
|
|
{
|
|
/* Invalidate the querytree and generic plan */
|
|
plansource->is_valid = false;
|
|
if (plansource->gplan)
|
|
plansource->gplan->is_valid = false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the query is currently valid, acquire locks on the referenced
|
|
* objects; then check again. We need to do it this way to cover the race
|
|
* condition that an invalidation message arrives before we get the locks.
|
|
*/
|
|
if (plansource->is_valid)
|
|
{
|
|
AcquirePlannerLocks(plansource->query_list, true);
|
|
|
|
/*
|
|
* By now, if any invalidation has happened, the inval callback
|
|
* functions will have marked the query invalid.
|
|
*/
|
|
if (plansource->is_valid)
|
|
{
|
|
/* Successfully revalidated and locked the query. */
|
|
return NIL;
|
|
}
|
|
|
|
/* Ooops, the race case happened. Release useless locks. */
|
|
AcquirePlannerLocks(plansource->query_list, false);
|
|
}
|
|
|
|
/*
|
|
* Discard the no-longer-useful query tree. (Note: we don't want to do
|
|
* this any earlier, else we'd not have been able to release locks
|
|
* correctly in the race condition case.)
|
|
*/
|
|
plansource->is_valid = false;
|
|
plansource->query_list = NIL;
|
|
plansource->relationOids = NIL;
|
|
plansource->invalItems = NIL;
|
|
plansource->search_path = NULL;
|
|
|
|
/*
|
|
* Free the query_context. We don't really expect MemoryContextDelete to
|
|
* fail, but just in case, make sure the CachedPlanSource is left in a
|
|
* reasonably sane state. (The generic plan won't get unlinked yet, but
|
|
* that's acceptable.)
|
|
*/
|
|
if (plansource->query_context)
|
|
{
|
|
MemoryContext qcxt = plansource->query_context;
|
|
|
|
plansource->query_context = NULL;
|
|
MemoryContextDelete(qcxt);
|
|
}
|
|
|
|
/* Drop the generic plan reference if any */
|
|
ReleaseGenericPlan(plansource);
|
|
|
|
/*
|
|
* Now re-do parse analysis and rewrite. This not incidentally acquires
|
|
* the locks we need to do planning safely.
|
|
*/
|
|
Assert(plansource->is_complete);
|
|
|
|
/*
|
|
* If a snapshot is already set (the normal case), we can just use that
|
|
* for parsing/planning. But if it isn't, install one. Note: no point in
|
|
* checking whether parse analysis requires a snapshot; utility commands
|
|
* don't have invalidatable plans, so we'd not get here for such a
|
|
* command.
|
|
*/
|
|
snapshot_set = false;
|
|
if (!ActiveSnapshotSet())
|
|
{
|
|
PushActiveSnapshot(GetTransactionSnapshot());
|
|
snapshot_set = true;
|
|
}
|
|
|
|
/*
|
|
* Run parse analysis and rule rewriting. The parser tends to scribble on
|
|
* its input, so we must copy the raw parse tree to prevent corruption of
|
|
* the cache.
|
|
*/
|
|
rawtree = copyObject(plansource->raw_parse_tree);
|
|
if (plansource->parserSetup != NULL)
|
|
tlist = pg_analyze_and_rewrite_params(rawtree,
|
|
plansource->query_string,
|
|
plansource->parserSetup,
|
|
plansource->parserSetupArg);
|
|
else
|
|
tlist = pg_analyze_and_rewrite(rawtree,
|
|
plansource->query_string,
|
|
plansource->param_types,
|
|
plansource->num_params);
|
|
|
|
/* Release snapshot if we got one */
|
|
if (snapshot_set)
|
|
PopActiveSnapshot();
|
|
|
|
/*
|
|
* Check or update the result tupdesc. XXX should we use a weaker
|
|
* condition than equalTupleDescs() here?
|
|
*
|
|
* We assume the parameter types didn't change from the first time, so no
|
|
* need to update that.
|
|
*/
|
|
resultDesc = PlanCacheComputeResultDesc(tlist);
|
|
if (resultDesc == NULL && plansource->resultDesc == NULL)
|
|
{
|
|
/* OK, doesn't return tuples */
|
|
}
|
|
else if (resultDesc == NULL || plansource->resultDesc == NULL ||
|
|
!equalTupleDescs(resultDesc, plansource->resultDesc))
|
|
{
|
|
/* can we give a better error message? */
|
|
if (plansource->fixed_result)
|
|
ereport(ERROR,
|
|
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
|
|
errmsg("cached plan must not change result type")));
|
|
oldcxt = MemoryContextSwitchTo(plansource->context);
|
|
if (resultDesc)
|
|
resultDesc = CreateTupleDescCopy(resultDesc);
|
|
if (plansource->resultDesc)
|
|
FreeTupleDesc(plansource->resultDesc);
|
|
plansource->resultDesc = resultDesc;
|
|
MemoryContextSwitchTo(oldcxt);
|
|
}
|
|
|
|
/*
|
|
* Allocate new query_context and copy the completed querytree into it.
|
|
* It's transient until we complete the copying and dependency extraction.
|
|
*/
|
|
querytree_context = AllocSetContextCreate(CurrentMemoryContext,
|
|
"CachedPlanQuery",
|
|
ALLOCSET_SMALL_MINSIZE,
|
|
ALLOCSET_SMALL_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
oldcxt = MemoryContextSwitchTo(querytree_context);
|
|
|
|
qlist = (List *) copyObject(tlist);
|
|
|
|
/*
|
|
* Use the planner machinery to extract dependencies. Data is saved in
|
|
* query_context. (We assume that not a lot of extra cruft is created by
|
|
* this call.)
|
|
*/
|
|
extract_query_dependencies((Node *) qlist,
|
|
&plansource->relationOids,
|
|
&plansource->invalItems);
|
|
|
|
/*
|
|
* Also save the current search_path in the query_context. (This should
|
|
* not generate much extra cruft either, since almost certainly the path
|
|
* is already valid.)
|
|
*/
|
|
plansource->search_path = GetOverrideSearchPath(querytree_context);
|
|
|
|
MemoryContextSwitchTo(oldcxt);
|
|
|
|
/* Now reparent the finished query_context and save the links */
|
|
MemoryContextSetParent(querytree_context, plansource->context);
|
|
|
|
plansource->query_context = querytree_context;
|
|
plansource->query_list = qlist;
|
|
|
|
/*
|
|
* Note: we do not reset generic_cost or total_custom_cost, although we
|
|
* could choose to do so. If the DDL or statistics change that prompted
|
|
* the invalidation meant a significant change in the cost estimates, it
|
|
* would be better to reset those variables and start fresh; but often it
|
|
* doesn't, and we're better retaining our hard-won knowledge about the
|
|
* relative costs.
|
|
*/
|
|
|
|
plansource->is_valid = true;
|
|
|
|
/* Return transient copy of querytrees for possible use in planning */
|
|
return tlist;
|
|
}
|
|
|
|
/*
|
|
* CheckCachedPlan: see if the CachedPlanSource's generic plan is valid.
|
|
*
|
|
* Caller must have already called RevalidateCachedQuery to verify that the
|
|
* querytree is up to date.
|
|
*
|
|
* On a "true" return, we have acquired the locks needed to run the plan.
|
|
* (We must do this for the "true" result to be race-condition-free.)
|
|
*/
|
|
static bool
|
|
CheckCachedPlan(CachedPlanSource *plansource)
|
|
{
|
|
CachedPlan *plan = plansource->gplan;
|
|
|
|
/* Assert that caller checked the querytree */
|
|
Assert(plansource->is_valid);
|
|
|
|
/* If there's no generic plan, just say "false" */
|
|
if (!plan)
|
|
return false;
|
|
|
|
Assert(plan->magic == CACHEDPLAN_MAGIC);
|
|
/* Generic plans are never one-shot */
|
|
Assert(!plan->is_oneshot);
|
|
|
|
/*
|
|
* If it appears valid, acquire locks and recheck; this is much the same
|
|
* logic as in RevalidateCachedQuery, but for a plan.
|
|
*/
|
|
if (plan->is_valid)
|
|
{
|
|
/*
|
|
* Plan must have positive refcount because it is referenced by
|
|
* plansource; so no need to fear it disappears under us here.
|
|
*/
|
|
Assert(plan->refcount > 0);
|
|
|
|
AcquireExecutorLocks(plan->stmt_list, true);
|
|
|
|
/*
|
|
* If plan was transient, check to see if TransactionXmin has
|
|
* advanced, and if so invalidate it.
|
|
*/
|
|
if (plan->is_valid &&
|
|
TransactionIdIsValid(plan->saved_xmin) &&
|
|
!TransactionIdEquals(plan->saved_xmin, TransactionXmin))
|
|
plan->is_valid = false;
|
|
|
|
/*
|
|
* By now, if any invalidation has happened, the inval callback
|
|
* functions will have marked the plan invalid.
|
|
*/
|
|
if (plan->is_valid)
|
|
{
|
|
/* Successfully revalidated and locked the query. */
|
|
return true;
|
|
}
|
|
|
|
/* Ooops, the race case happened. Release useless locks. */
|
|
AcquireExecutorLocks(plan->stmt_list, false);
|
|
}
|
|
|
|
/*
|
|
* Plan has been invalidated, so unlink it from the parent and release it.
|
|
*/
|
|
ReleaseGenericPlan(plansource);
|
|
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* BuildCachedPlan: construct a new CachedPlan from a CachedPlanSource.
|
|
*
|
|
* qlist should be the result value from a previous RevalidateCachedQuery,
|
|
* or it can be set to NIL if we need to re-copy the plansource's query_list.
|
|
*
|
|
* To build a generic, parameter-value-independent plan, pass NULL for
|
|
* boundParams. To build a custom plan, pass the actual parameter values via
|
|
* boundParams. For best effect, the PARAM_FLAG_CONST flag should be set on
|
|
* each parameter value; otherwise the planner will treat the value as a
|
|
* hint rather than a hard constant.
|
|
*
|
|
* Planning work is done in the caller's memory context. The finished plan
|
|
* is in a child memory context, which typically should get reparented
|
|
* (unless this is a one-shot plan, in which case we don't copy the plan).
|
|
*/
|
|
static CachedPlan *
|
|
BuildCachedPlan(CachedPlanSource *plansource, List *qlist,
|
|
ParamListInfo boundParams)
|
|
{
|
|
CachedPlan *plan;
|
|
List *plist;
|
|
bool snapshot_set;
|
|
bool spi_pushed;
|
|
MemoryContext plan_context;
|
|
MemoryContext oldcxt = CurrentMemoryContext;
|
|
|
|
/*
|
|
* Normally the querytree should be valid already, but if it's not,
|
|
* rebuild it.
|
|
*
|
|
* NOTE: GetCachedPlan should have called RevalidateCachedQuery first, so
|
|
* we ought to be holding sufficient locks to prevent any invalidation.
|
|
* However, if we're building a custom plan after having built and
|
|
* rejected a generic plan, it's possible to reach here with is_valid
|
|
* false due to an invalidation while making the generic plan. In theory
|
|
* the invalidation must be a false positive, perhaps a consequence of an
|
|
* sinval reset event or the CLOBBER_CACHE_ALWAYS debug code. But for
|
|
* safety, let's treat it as real and redo the RevalidateCachedQuery call.
|
|
*/
|
|
if (!plansource->is_valid)
|
|
qlist = RevalidateCachedQuery(plansource);
|
|
|
|
/*
|
|
* If we don't already have a copy of the querytree list that can be
|
|
* scribbled on by the planner, make one. For a one-shot plan, we assume
|
|
* it's okay to scribble on the original query_list.
|
|
*/
|
|
if (qlist == NIL)
|
|
{
|
|
if (!plansource->is_oneshot)
|
|
qlist = (List *) copyObject(plansource->query_list);
|
|
else
|
|
qlist = plansource->query_list;
|
|
}
|
|
|
|
/*
|
|
* If a snapshot is already set (the normal case), we can just use that
|
|
* for planning. But if it isn't, and we need one, install one.
|
|
*/
|
|
snapshot_set = false;
|
|
if (!ActiveSnapshotSet() &&
|
|
analyze_requires_snapshot(plansource->raw_parse_tree))
|
|
{
|
|
PushActiveSnapshot(GetTransactionSnapshot());
|
|
snapshot_set = true;
|
|
}
|
|
|
|
/*
|
|
* The planner may try to call SPI-using functions, which causes a problem
|
|
* if we're already inside one. Rather than expect all SPI-using code to
|
|
* do SPI_push whenever a replan could happen, it seems best to take care
|
|
* of the case here.
|
|
*/
|
|
spi_pushed = SPI_push_conditional();
|
|
|
|
/*
|
|
* Generate the plan.
|
|
*/
|
|
plist = pg_plan_queries(qlist, plansource->cursor_options, boundParams);
|
|
|
|
/* Clean up SPI state */
|
|
SPI_pop_conditional(spi_pushed);
|
|
|
|
/* Release snapshot if we got one */
|
|
if (snapshot_set)
|
|
PopActiveSnapshot();
|
|
|
|
/*
|
|
* Normally we make a dedicated memory context for the CachedPlan and its
|
|
* subsidiary data. (It's probably not going to be large, but just in
|
|
* case, use the default maxsize parameter. It's transient for the
|
|
* moment.) But for a one-shot plan, we just leave it in the caller's
|
|
* memory context.
|
|
*/
|
|
if (!plansource->is_oneshot)
|
|
{
|
|
plan_context = AllocSetContextCreate(CurrentMemoryContext,
|
|
"CachedPlan",
|
|
ALLOCSET_SMALL_MINSIZE,
|
|
ALLOCSET_SMALL_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
|
|
/*
|
|
* Copy plan into the new context.
|
|
*/
|
|
MemoryContextSwitchTo(plan_context);
|
|
|
|
plist = (List *) copyObject(plist);
|
|
}
|
|
else
|
|
plan_context = CurrentMemoryContext;
|
|
|
|
/*
|
|
* Create and fill the CachedPlan struct within the new context.
|
|
*/
|
|
plan = (CachedPlan *) palloc(sizeof(CachedPlan));
|
|
plan->magic = CACHEDPLAN_MAGIC;
|
|
plan->stmt_list = plist;
|
|
if (plan_list_is_transient(plist))
|
|
{
|
|
Assert(TransactionIdIsNormal(TransactionXmin));
|
|
plan->saved_xmin = TransactionXmin;
|
|
}
|
|
else
|
|
plan->saved_xmin = InvalidTransactionId;
|
|
plan->refcount = 0;
|
|
plan->context = plan_context;
|
|
plan->is_oneshot = plansource->is_oneshot;
|
|
plan->is_saved = false;
|
|
plan->is_valid = true;
|
|
|
|
/* assign generation number to new plan */
|
|
plan->generation = ++(plansource->generation);
|
|
|
|
MemoryContextSwitchTo(oldcxt);
|
|
|
|
return plan;
|
|
}
|
|
|
|
/*
|
|
* choose_custom_plan: choose whether to use custom or generic plan
|
|
*
|
|
* This defines the policy followed by GetCachedPlan.
|
|
*/
|
|
static bool
|
|
choose_custom_plan(CachedPlanSource *plansource, ParamListInfo boundParams)
|
|
{
|
|
double avg_custom_cost;
|
|
|
|
/* One-shot plans will always be considered custom */
|
|
if (plansource->is_oneshot)
|
|
return true;
|
|
|
|
/* Otherwise, never any point in a custom plan if there's no parameters */
|
|
if (boundParams == NULL)
|
|
return false;
|
|
/* ... nor for transaction control statements */
|
|
if (IsTransactionStmtPlan(plansource))
|
|
return false;
|
|
|
|
/* See if caller wants to force the decision */
|
|
if (plansource->cursor_options & CURSOR_OPT_GENERIC_PLAN)
|
|
return false;
|
|
if (plansource->cursor_options & CURSOR_OPT_CUSTOM_PLAN)
|
|
return true;
|
|
|
|
/* Generate custom plans until we have done at least 5 (arbitrary) */
|
|
if (plansource->num_custom_plans < 5)
|
|
return true;
|
|
|
|
avg_custom_cost = plansource->total_custom_cost / plansource->num_custom_plans;
|
|
|
|
/*
|
|
* Prefer generic plan if it's less than 10% more expensive than average
|
|
* custom plan. This threshold is a bit arbitrary; it'd be better if we
|
|
* had some means of comparing planning time to the estimated runtime cost
|
|
* differential.
|
|
*
|
|
* Note that if generic_cost is -1 (indicating we've not yet determined
|
|
* the generic plan cost), we'll always prefer generic at this point.
|
|
*/
|
|
if (plansource->generic_cost < avg_custom_cost * 1.1)
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* cached_plan_cost: calculate estimated cost of a plan
|
|
*/
|
|
static double
|
|
cached_plan_cost(CachedPlan *plan)
|
|
{
|
|
double result = 0;
|
|
ListCell *lc;
|
|
|
|
foreach(lc, plan->stmt_list)
|
|
{
|
|
PlannedStmt *plannedstmt = (PlannedStmt *) lfirst(lc);
|
|
|
|
if (!IsA(plannedstmt, PlannedStmt))
|
|
continue; /* Ignore utility statements */
|
|
|
|
result += plannedstmt->planTree->total_cost;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
/*
|
|
* GetCachedPlan: get a cached plan from a CachedPlanSource.
|
|
*
|
|
* This function hides the logic that decides whether to use a generic
|
|
* plan or a custom plan for the given parameters: the caller does not know
|
|
* which it will get.
|
|
*
|
|
* On return, the plan is valid and we have sufficient locks to begin
|
|
* execution.
|
|
*
|
|
* On return, the refcount of the plan has been incremented; a later
|
|
* ReleaseCachedPlan() call is expected. The refcount has been reported
|
|
* to the CurrentResourceOwner if useResOwner is true (note that that must
|
|
* only be true if it's a "saved" CachedPlanSource).
|
|
*
|
|
* Note: if any replanning activity is required, the caller's memory context
|
|
* is used for that work.
|
|
*/
|
|
CachedPlan *
|
|
GetCachedPlan(CachedPlanSource *plansource, ParamListInfo boundParams,
|
|
bool useResOwner)
|
|
{
|
|
CachedPlan *plan;
|
|
List *qlist;
|
|
bool customplan;
|
|
|
|
/* Assert caller is doing things in a sane order */
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
Assert(plansource->is_complete);
|
|
/* This seems worth a real test, though */
|
|
if (useResOwner && !plansource->is_saved)
|
|
elog(ERROR, "cannot apply ResourceOwner to non-saved cached plan");
|
|
|
|
/* Make sure the querytree list is valid and we have parse-time locks */
|
|
qlist = RevalidateCachedQuery(plansource);
|
|
|
|
/* Decide whether to use a custom plan */
|
|
customplan = choose_custom_plan(plansource, boundParams);
|
|
|
|
if (!customplan)
|
|
{
|
|
if (CheckCachedPlan(plansource))
|
|
{
|
|
/* We want a generic plan, and we already have a valid one */
|
|
plan = plansource->gplan;
|
|
Assert(plan->magic == CACHEDPLAN_MAGIC);
|
|
}
|
|
else
|
|
{
|
|
/* Build a new generic plan */
|
|
plan = BuildCachedPlan(plansource, qlist, NULL);
|
|
/* Just make real sure plansource->gplan is clear */
|
|
ReleaseGenericPlan(plansource);
|
|
/* Link the new generic plan into the plansource */
|
|
plansource->gplan = plan;
|
|
plan->refcount++;
|
|
/* Immediately reparent into appropriate context */
|
|
if (plansource->is_saved)
|
|
{
|
|
/* saved plans all live under CacheMemoryContext */
|
|
MemoryContextSetParent(plan->context, CacheMemoryContext);
|
|
plan->is_saved = true;
|
|
}
|
|
else
|
|
{
|
|
/* otherwise, it should be a sibling of the plansource */
|
|
MemoryContextSetParent(plan->context,
|
|
MemoryContextGetParent(plansource->context));
|
|
}
|
|
/* Update generic_cost whenever we make a new generic plan */
|
|
plansource->generic_cost = cached_plan_cost(plan);
|
|
|
|
/*
|
|
* If, based on the now-known value of generic_cost, we'd not have
|
|
* chosen to use a generic plan, then forget it and make a custom
|
|
* plan. This is a bit of a wart but is necessary to avoid a
|
|
* glitch in behavior when the custom plans are consistently big
|
|
* winners; at some point we'll experiment with a generic plan and
|
|
* find it's a loser, but we don't want to actually execute that
|
|
* plan.
|
|
*/
|
|
customplan = choose_custom_plan(plansource, boundParams);
|
|
|
|
/*
|
|
* If we choose to plan again, we need to re-copy the query_list,
|
|
* since the planner probably scribbled on it. We can force
|
|
* BuildCachedPlan to do that by passing NIL.
|
|
*/
|
|
qlist = NIL;
|
|
}
|
|
}
|
|
|
|
if (customplan)
|
|
{
|
|
/* Build a custom plan */
|
|
plan = BuildCachedPlan(plansource, qlist, boundParams);
|
|
/* Accumulate total costs of custom plans, but 'ware overflow */
|
|
if (plansource->num_custom_plans < INT_MAX)
|
|
{
|
|
plansource->total_custom_cost += cached_plan_cost(plan);
|
|
plansource->num_custom_plans++;
|
|
}
|
|
}
|
|
|
|
/* Flag the plan as in use by caller */
|
|
if (useResOwner)
|
|
ResourceOwnerEnlargePlanCacheRefs(CurrentResourceOwner);
|
|
plan->refcount++;
|
|
if (useResOwner)
|
|
ResourceOwnerRememberPlanCacheRef(CurrentResourceOwner, plan);
|
|
|
|
/*
|
|
* Saved plans should be under CacheMemoryContext so they will not go away
|
|
* until their reference count goes to zero. In the generic-plan cases we
|
|
* already took care of that, but for a custom plan, do it as soon as we
|
|
* have created a reference-counted link.
|
|
*/
|
|
if (customplan && plansource->is_saved)
|
|
{
|
|
MemoryContextSetParent(plan->context, CacheMemoryContext);
|
|
plan->is_saved = true;
|
|
}
|
|
|
|
return plan;
|
|
}
|
|
|
|
/*
|
|
* ReleaseCachedPlan: release active use of a cached plan.
|
|
*
|
|
* This decrements the reference count, and frees the plan if the count
|
|
* has thereby gone to zero. If useResOwner is true, it is assumed that
|
|
* the reference count is managed by the CurrentResourceOwner.
|
|
*
|
|
* Note: useResOwner = false is used for releasing references that are in
|
|
* persistent data structures, such as the parent CachedPlanSource or a
|
|
* Portal. Transient references should be protected by a resource owner.
|
|
*/
|
|
void
|
|
ReleaseCachedPlan(CachedPlan *plan, bool useResOwner)
|
|
{
|
|
Assert(plan->magic == CACHEDPLAN_MAGIC);
|
|
if (useResOwner)
|
|
{
|
|
Assert(plan->is_saved);
|
|
ResourceOwnerForgetPlanCacheRef(CurrentResourceOwner, plan);
|
|
}
|
|
Assert(plan->refcount > 0);
|
|
plan->refcount--;
|
|
if (plan->refcount == 0)
|
|
{
|
|
/* Mark it no longer valid */
|
|
plan->magic = 0;
|
|
|
|
/* One-shot plans do not own their context, so we can't free them */
|
|
if (!plan->is_oneshot)
|
|
MemoryContextDelete(plan->context);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* CachedPlanSetParentContext: move a CachedPlanSource to a new memory context
|
|
*
|
|
* This can only be applied to unsaved plans; once saved, a plan always
|
|
* lives underneath CacheMemoryContext.
|
|
*/
|
|
void
|
|
CachedPlanSetParentContext(CachedPlanSource *plansource,
|
|
MemoryContext newcontext)
|
|
{
|
|
/* Assert caller is doing things in a sane order */
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
Assert(plansource->is_complete);
|
|
|
|
/* These seem worth real tests, though */
|
|
if (plansource->is_saved)
|
|
elog(ERROR, "cannot move a saved cached plan to another context");
|
|
if (plansource->is_oneshot)
|
|
elog(ERROR, "cannot move a one-shot cached plan to another context");
|
|
|
|
/* OK, let the caller keep the plan where he wishes */
|
|
MemoryContextSetParent(plansource->context, newcontext);
|
|
|
|
/*
|
|
* The query_context needs no special handling, since it's a child of
|
|
* plansource->context. But if there's a generic plan, it should be
|
|
* maintained as a sibling of plansource->context.
|
|
*/
|
|
if (plansource->gplan)
|
|
{
|
|
Assert(plansource->gplan->magic == CACHEDPLAN_MAGIC);
|
|
MemoryContextSetParent(plansource->gplan->context, newcontext);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* CopyCachedPlan: make a copy of a CachedPlanSource
|
|
*
|
|
* This is a convenience routine that does the equivalent of
|
|
* CreateCachedPlan + CompleteCachedPlan, using the data stored in the
|
|
* input CachedPlanSource. The result is therefore "unsaved" (regardless
|
|
* of the state of the source), and we don't copy any generic plan either.
|
|
* The result will be currently valid, or not, the same as the source.
|
|
*/
|
|
CachedPlanSource *
|
|
CopyCachedPlan(CachedPlanSource *plansource)
|
|
{
|
|
CachedPlanSource *newsource;
|
|
MemoryContext source_context;
|
|
MemoryContext querytree_context;
|
|
MemoryContext oldcxt;
|
|
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
Assert(plansource->is_complete);
|
|
|
|
/*
|
|
* One-shot plans can't be copied, because we haven't taken care that
|
|
* parsing/planning didn't scribble on the raw parse tree or querytrees.
|
|
*/
|
|
if (plansource->is_oneshot)
|
|
elog(ERROR, "cannot copy a one-shot cached plan");
|
|
|
|
source_context = AllocSetContextCreate(CurrentMemoryContext,
|
|
"CachedPlanSource",
|
|
ALLOCSET_SMALL_MINSIZE,
|
|
ALLOCSET_SMALL_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
|
|
oldcxt = MemoryContextSwitchTo(source_context);
|
|
|
|
newsource = (CachedPlanSource *) palloc0(sizeof(CachedPlanSource));
|
|
newsource->magic = CACHEDPLANSOURCE_MAGIC;
|
|
newsource->raw_parse_tree = copyObject(plansource->raw_parse_tree);
|
|
newsource->query_string = pstrdup(plansource->query_string);
|
|
newsource->commandTag = plansource->commandTag;
|
|
if (plansource->num_params > 0)
|
|
{
|
|
newsource->param_types = (Oid *)
|
|
palloc(plansource->num_params * sizeof(Oid));
|
|
memcpy(newsource->param_types, plansource->param_types,
|
|
plansource->num_params * sizeof(Oid));
|
|
}
|
|
else
|
|
newsource->param_types = NULL;
|
|
newsource->num_params = plansource->num_params;
|
|
newsource->parserSetup = plansource->parserSetup;
|
|
newsource->parserSetupArg = plansource->parserSetupArg;
|
|
newsource->cursor_options = plansource->cursor_options;
|
|
newsource->fixed_result = plansource->fixed_result;
|
|
if (plansource->resultDesc)
|
|
newsource->resultDesc = CreateTupleDescCopy(plansource->resultDesc);
|
|
else
|
|
newsource->resultDesc = NULL;
|
|
newsource->context = source_context;
|
|
|
|
querytree_context = AllocSetContextCreate(source_context,
|
|
"CachedPlanQuery",
|
|
ALLOCSET_SMALL_MINSIZE,
|
|
ALLOCSET_SMALL_INITSIZE,
|
|
ALLOCSET_DEFAULT_MAXSIZE);
|
|
MemoryContextSwitchTo(querytree_context);
|
|
newsource->query_list = (List *) copyObject(plansource->query_list);
|
|
newsource->relationOids = (List *) copyObject(plansource->relationOids);
|
|
newsource->invalItems = (List *) copyObject(plansource->invalItems);
|
|
if (plansource->search_path)
|
|
newsource->search_path = CopyOverrideSearchPath(plansource->search_path);
|
|
newsource->query_context = querytree_context;
|
|
|
|
newsource->gplan = NULL;
|
|
|
|
newsource->is_oneshot = false;
|
|
newsource->is_complete = true;
|
|
newsource->is_saved = false;
|
|
newsource->is_valid = plansource->is_valid;
|
|
newsource->generation = plansource->generation;
|
|
newsource->next_saved = NULL;
|
|
|
|
/* We may as well copy any acquired cost knowledge */
|
|
newsource->generic_cost = plansource->generic_cost;
|
|
newsource->total_custom_cost = plansource->total_custom_cost;
|
|
newsource->num_custom_plans = plansource->num_custom_plans;
|
|
|
|
MemoryContextSwitchTo(oldcxt);
|
|
|
|
return newsource;
|
|
}
|
|
|
|
/*
|
|
* CachedPlanIsValid: test whether the rewritten querytree within a
|
|
* CachedPlanSource is currently valid (that is, not marked as being in need
|
|
* of revalidation).
|
|
*
|
|
* This result is only trustworthy (ie, free from race conditions) if
|
|
* the caller has acquired locks on all the relations used in the plan.
|
|
*/
|
|
bool
|
|
CachedPlanIsValid(CachedPlanSource *plansource)
|
|
{
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
return plansource->is_valid;
|
|
}
|
|
|
|
/*
|
|
* CachedPlanGetTargetList: return tlist, if any, describing plan's output
|
|
*
|
|
* The result is guaranteed up-to-date. However, it is local storage
|
|
* within the cached plan, and may disappear next time the plan is updated.
|
|
*/
|
|
List *
|
|
CachedPlanGetTargetList(CachedPlanSource *plansource)
|
|
{
|
|
Node *pstmt;
|
|
|
|
/* Assert caller is doing things in a sane order */
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
Assert(plansource->is_complete);
|
|
|
|
/*
|
|
* No work needed if statement doesn't return tuples (we assume this
|
|
* feature cannot be changed by an invalidation)
|
|
*/
|
|
if (plansource->resultDesc == NULL)
|
|
return NIL;
|
|
|
|
/* Make sure the querytree list is valid and we have parse-time locks */
|
|
RevalidateCachedQuery(plansource);
|
|
|
|
/* Get the primary statement and find out what it returns */
|
|
pstmt = PortalListGetPrimaryStmt(plansource->query_list);
|
|
|
|
return FetchStatementTargetList(pstmt);
|
|
}
|
|
|
|
/*
|
|
* AcquireExecutorLocks: acquire locks needed for execution of a cached plan;
|
|
* or release them if acquire is false.
|
|
*/
|
|
static void
|
|
AcquireExecutorLocks(List *stmt_list, bool acquire)
|
|
{
|
|
ListCell *lc1;
|
|
|
|
foreach(lc1, stmt_list)
|
|
{
|
|
PlannedStmt *plannedstmt = (PlannedStmt *) lfirst(lc1);
|
|
int rt_index;
|
|
ListCell *lc2;
|
|
|
|
Assert(!IsA(plannedstmt, Query));
|
|
if (!IsA(plannedstmt, PlannedStmt))
|
|
{
|
|
/*
|
|
* Ignore utility statements, except those (such as EXPLAIN) that
|
|
* contain a parsed-but-not-planned query. Note: it's okay to use
|
|
* ScanQueryForLocks, even though the query hasn't been through
|
|
* rule rewriting, because rewriting doesn't change the query
|
|
* representation.
|
|
*/
|
|
Query *query = UtilityContainsQuery((Node *) plannedstmt);
|
|
|
|
if (query)
|
|
ScanQueryForLocks(query, acquire);
|
|
continue;
|
|
}
|
|
|
|
rt_index = 0;
|
|
foreach(lc2, plannedstmt->rtable)
|
|
{
|
|
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc2);
|
|
LOCKMODE lockmode;
|
|
PlanRowMark *rc;
|
|
|
|
rt_index++;
|
|
|
|
if (rte->rtekind != RTE_RELATION)
|
|
continue;
|
|
|
|
/*
|
|
* Acquire the appropriate type of lock on each relation OID. Note
|
|
* that we don't actually try to open the rel, and hence will not
|
|
* fail if it's been dropped entirely --- we'll just transiently
|
|
* acquire a non-conflicting lock.
|
|
*/
|
|
if (list_member_int(plannedstmt->resultRelations, rt_index))
|
|
lockmode = RowExclusiveLock;
|
|
else if ((rc = get_plan_rowmark(plannedstmt->rowMarks, rt_index)) != NULL &&
|
|
RowMarkRequiresRowShareLock(rc->markType))
|
|
lockmode = RowShareLock;
|
|
else
|
|
lockmode = AccessShareLock;
|
|
|
|
if (acquire)
|
|
LockRelationOid(rte->relid, lockmode);
|
|
else
|
|
UnlockRelationOid(rte->relid, lockmode);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* AcquirePlannerLocks: acquire locks needed for planning of a querytree list;
|
|
* or release them if acquire is false.
|
|
*
|
|
* Note that we don't actually try to open the relations, and hence will not
|
|
* fail if one has been dropped entirely --- we'll just transiently acquire
|
|
* a non-conflicting lock.
|
|
*/
|
|
static void
|
|
AcquirePlannerLocks(List *stmt_list, bool acquire)
|
|
{
|
|
ListCell *lc;
|
|
|
|
foreach(lc, stmt_list)
|
|
{
|
|
Query *query = (Query *) lfirst(lc);
|
|
|
|
Assert(IsA(query, Query));
|
|
|
|
if (query->commandType == CMD_UTILITY)
|
|
{
|
|
/* Ignore utility statements, unless they contain a Query */
|
|
query = UtilityContainsQuery(query->utilityStmt);
|
|
if (query)
|
|
ScanQueryForLocks(query, acquire);
|
|
continue;
|
|
}
|
|
|
|
ScanQueryForLocks(query, acquire);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* ScanQueryForLocks: recursively scan one Query for AcquirePlannerLocks.
|
|
*/
|
|
static void
|
|
ScanQueryForLocks(Query *parsetree, bool acquire)
|
|
{
|
|
ListCell *lc;
|
|
int rt_index;
|
|
|
|
/* Shouldn't get called on utility commands */
|
|
Assert(parsetree->commandType != CMD_UTILITY);
|
|
|
|
/*
|
|
* First, process RTEs of the current query level.
|
|
*/
|
|
rt_index = 0;
|
|
foreach(lc, parsetree->rtable)
|
|
{
|
|
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
|
|
LOCKMODE lockmode;
|
|
|
|
rt_index++;
|
|
switch (rte->rtekind)
|
|
{
|
|
case RTE_RELATION:
|
|
/* Acquire or release the appropriate type of lock */
|
|
if (rt_index == parsetree->resultRelation)
|
|
lockmode = RowExclusiveLock;
|
|
else if (get_parse_rowmark(parsetree, rt_index) != NULL)
|
|
lockmode = RowShareLock;
|
|
else
|
|
lockmode = AccessShareLock;
|
|
if (acquire)
|
|
LockRelationOid(rte->relid, lockmode);
|
|
else
|
|
UnlockRelationOid(rte->relid, lockmode);
|
|
break;
|
|
|
|
case RTE_SUBQUERY:
|
|
/* Recurse into subquery-in-FROM */
|
|
ScanQueryForLocks(rte->subquery, acquire);
|
|
break;
|
|
|
|
default:
|
|
/* ignore other types of RTEs */
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Recurse into subquery-in-WITH */
|
|
foreach(lc, parsetree->cteList)
|
|
{
|
|
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
|
|
|
|
ScanQueryForLocks((Query *) cte->ctequery, acquire);
|
|
}
|
|
|
|
/*
|
|
* Recurse into sublink subqueries, too. But we already did the ones in
|
|
* the rtable and cteList.
|
|
*/
|
|
if (parsetree->hasSubLinks)
|
|
{
|
|
query_tree_walker(parsetree, ScanQueryWalker,
|
|
(void *) &acquire,
|
|
QTW_IGNORE_RC_SUBQUERIES);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Walker to find sublink subqueries for ScanQueryForLocks
|
|
*/
|
|
static bool
|
|
ScanQueryWalker(Node *node, bool *acquire)
|
|
{
|
|
if (node == NULL)
|
|
return false;
|
|
if (IsA(node, SubLink))
|
|
{
|
|
SubLink *sub = (SubLink *) node;
|
|
|
|
/* Do what we came for */
|
|
ScanQueryForLocks((Query *) sub->subselect, *acquire);
|
|
/* Fall through to process lefthand args of SubLink */
|
|
}
|
|
|
|
/*
|
|
* Do NOT recurse into Query nodes, because ScanQueryForLocks already
|
|
* processed subselects of subselects for us.
|
|
*/
|
|
return expression_tree_walker(node, ScanQueryWalker,
|
|
(void *) acquire);
|
|
}
|
|
|
|
/*
|
|
* plan_list_is_transient: check if any of the plans in the list are transient.
|
|
*/
|
|
static bool
|
|
plan_list_is_transient(List *stmt_list)
|
|
{
|
|
ListCell *lc;
|
|
|
|
foreach(lc, stmt_list)
|
|
{
|
|
PlannedStmt *plannedstmt = (PlannedStmt *) lfirst(lc);
|
|
|
|
if (!IsA(plannedstmt, PlannedStmt))
|
|
continue; /* Ignore utility statements */
|
|
|
|
if (plannedstmt->transientPlan)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* PlanCacheComputeResultDesc: given a list of analyzed-and-rewritten Queries,
|
|
* determine the result tupledesc it will produce. Returns NULL if the
|
|
* execution will not return tuples.
|
|
*
|
|
* Note: the result is created or copied into current memory context.
|
|
*/
|
|
static TupleDesc
|
|
PlanCacheComputeResultDesc(List *stmt_list)
|
|
{
|
|
Query *query;
|
|
|
|
switch (ChoosePortalStrategy(stmt_list))
|
|
{
|
|
case PORTAL_ONE_SELECT:
|
|
case PORTAL_ONE_MOD_WITH:
|
|
query = (Query *) linitial(stmt_list);
|
|
Assert(IsA(query, Query));
|
|
return ExecCleanTypeFromTL(query->targetList, false);
|
|
|
|
case PORTAL_ONE_RETURNING:
|
|
query = (Query *) PortalListGetPrimaryStmt(stmt_list);
|
|
Assert(IsA(query, Query));
|
|
Assert(query->returningList);
|
|
return ExecCleanTypeFromTL(query->returningList, false);
|
|
|
|
case PORTAL_UTIL_SELECT:
|
|
query = (Query *) linitial(stmt_list);
|
|
Assert(IsA(query, Query));
|
|
Assert(query->utilityStmt);
|
|
return UtilityTupleDescriptor(query->utilityStmt);
|
|
|
|
case PORTAL_MULTI_QUERY:
|
|
/* will not return tuples */
|
|
break;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* PlanCacheRelCallback
|
|
* Relcache inval callback function
|
|
*
|
|
* Invalidate all plans mentioning the given rel, or all plans mentioning
|
|
* any rel at all if relid == InvalidOid.
|
|
*/
|
|
static void
|
|
PlanCacheRelCallback(Datum arg, Oid relid)
|
|
{
|
|
CachedPlanSource *plansource;
|
|
|
|
for (plansource = first_saved_plan; plansource; plansource = plansource->next_saved)
|
|
{
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
|
|
/* No work if it's already invalidated */
|
|
if (!plansource->is_valid)
|
|
continue;
|
|
|
|
/* Never invalidate transaction control commands */
|
|
if (IsTransactionStmtPlan(plansource))
|
|
continue;
|
|
|
|
/*
|
|
* Check the dependency list for the rewritten querytree.
|
|
*/
|
|
if ((relid == InvalidOid) ? plansource->relationOids != NIL :
|
|
list_member_oid(plansource->relationOids, relid))
|
|
{
|
|
/* Invalidate the querytree and generic plan */
|
|
plansource->is_valid = false;
|
|
if (plansource->gplan)
|
|
plansource->gplan->is_valid = false;
|
|
}
|
|
|
|
/*
|
|
* The generic plan, if any, could have more dependencies than the
|
|
* querytree does, so we have to check it too.
|
|
*/
|
|
if (plansource->gplan && plansource->gplan->is_valid)
|
|
{
|
|
ListCell *lc;
|
|
|
|
foreach(lc, plansource->gplan->stmt_list)
|
|
{
|
|
PlannedStmt *plannedstmt = (PlannedStmt *) lfirst(lc);
|
|
|
|
Assert(!IsA(plannedstmt, Query));
|
|
if (!IsA(plannedstmt, PlannedStmt))
|
|
continue; /* Ignore utility statements */
|
|
if ((relid == InvalidOid) ? plannedstmt->relationOids != NIL :
|
|
list_member_oid(plannedstmt->relationOids, relid))
|
|
{
|
|
/* Invalidate the generic plan only */
|
|
plansource->gplan->is_valid = false;
|
|
break; /* out of stmt_list scan */
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* PlanCacheFuncCallback
|
|
* Syscache inval callback function for PROCOID cache
|
|
*
|
|
* Invalidate all plans mentioning the object with the specified hash value,
|
|
* or all plans mentioning any member of this cache if hashvalue == 0.
|
|
*
|
|
* Note that the coding would support use for multiple caches, but right
|
|
* now only user-defined functions are tracked this way.
|
|
*/
|
|
static void
|
|
PlanCacheFuncCallback(Datum arg, int cacheid, uint32 hashvalue)
|
|
{
|
|
CachedPlanSource *plansource;
|
|
|
|
for (plansource = first_saved_plan; plansource; plansource = plansource->next_saved)
|
|
{
|
|
ListCell *lc;
|
|
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
|
|
/* No work if it's already invalidated */
|
|
if (!plansource->is_valid)
|
|
continue;
|
|
|
|
/* Never invalidate transaction control commands */
|
|
if (IsTransactionStmtPlan(plansource))
|
|
continue;
|
|
|
|
/*
|
|
* Check the dependency list for the rewritten querytree.
|
|
*/
|
|
foreach(lc, plansource->invalItems)
|
|
{
|
|
PlanInvalItem *item = (PlanInvalItem *) lfirst(lc);
|
|
|
|
if (item->cacheId != cacheid)
|
|
continue;
|
|
if (hashvalue == 0 ||
|
|
item->hashValue == hashvalue)
|
|
{
|
|
/* Invalidate the querytree and generic plan */
|
|
plansource->is_valid = false;
|
|
if (plansource->gplan)
|
|
plansource->gplan->is_valid = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The generic plan, if any, could have more dependencies than the
|
|
* querytree does, so we have to check it too.
|
|
*/
|
|
if (plansource->gplan && plansource->gplan->is_valid)
|
|
{
|
|
foreach(lc, plansource->gplan->stmt_list)
|
|
{
|
|
PlannedStmt *plannedstmt = (PlannedStmt *) lfirst(lc);
|
|
ListCell *lc3;
|
|
|
|
Assert(!IsA(plannedstmt, Query));
|
|
if (!IsA(plannedstmt, PlannedStmt))
|
|
continue; /* Ignore utility statements */
|
|
foreach(lc3, plannedstmt->invalItems)
|
|
{
|
|
PlanInvalItem *item = (PlanInvalItem *) lfirst(lc3);
|
|
|
|
if (item->cacheId != cacheid)
|
|
continue;
|
|
if (hashvalue == 0 ||
|
|
item->hashValue == hashvalue)
|
|
{
|
|
/* Invalidate the generic plan only */
|
|
plansource->gplan->is_valid = false;
|
|
break; /* out of invalItems scan */
|
|
}
|
|
}
|
|
if (!plansource->gplan->is_valid)
|
|
break; /* out of stmt_list scan */
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* PlanCacheSysCallback
|
|
* Syscache inval callback function for other caches
|
|
*
|
|
* Just invalidate everything...
|
|
*/
|
|
static void
|
|
PlanCacheSysCallback(Datum arg, int cacheid, uint32 hashvalue)
|
|
{
|
|
ResetPlanCache();
|
|
}
|
|
|
|
/*
|
|
* ResetPlanCache: invalidate all cached plans.
|
|
*/
|
|
void
|
|
ResetPlanCache(void)
|
|
{
|
|
CachedPlanSource *plansource;
|
|
|
|
for (plansource = first_saved_plan; plansource; plansource = plansource->next_saved)
|
|
{
|
|
ListCell *lc;
|
|
|
|
Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC);
|
|
|
|
/* No work if it's already invalidated */
|
|
if (!plansource->is_valid)
|
|
continue;
|
|
|
|
/*
|
|
* We *must not* mark transaction control statements as invalid,
|
|
* particularly not ROLLBACK, because they may need to be executed in
|
|
* aborted transactions when we can't revalidate them (cf bug #5269).
|
|
*/
|
|
if (IsTransactionStmtPlan(plansource))
|
|
continue;
|
|
|
|
/*
|
|
* In general there is no point in invalidating utility statements
|
|
* since they have no plans anyway. So invalidate it only if it
|
|
* contains at least one non-utility statement, or contains a utility
|
|
* statement that contains a pre-analyzed query (which could have
|
|
* dependencies.)
|
|
*/
|
|
foreach(lc, plansource->query_list)
|
|
{
|
|
Query *query = (Query *) lfirst(lc);
|
|
|
|
Assert(IsA(query, Query));
|
|
if (query->commandType != CMD_UTILITY ||
|
|
UtilityContainsQuery(query->utilityStmt))
|
|
{
|
|
/* non-utility statement, so invalidate */
|
|
plansource->is_valid = false;
|
|
if (plansource->gplan)
|
|
plansource->gplan->is_valid = false;
|
|
/* no need to look further */
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|