diff options
Diffstat (limited to 'src/backend/utils')
| -rw-r--r-- | src/backend/utils/cache/plancache.c | 69 |
1 files changed, 27 insertions, 42 deletions
diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c index 25e951e9c10..51c1131d6d5 100644 --- a/src/backend/utils/cache/plancache.c +++ b/src/backend/utils/cache/plancache.c @@ -77,13 +77,15 @@ /* * We must skip "overhead" operations that involve database access when the - * cached plan's subject statement is a transaction control command. - * For the convenience of postgres.c, treat empty statements as control - * commands too. + * cached plan's subject statement is a transaction control command or one + * that requires a snapshot not to be set yet (such as SET or LOCK). More + * generally, statements that do not require parse analysis/rewrite/plan + * activity never need to be revalidated, so we can treat them all like that. + * For the convenience of postgres.c, treat empty statements that way too. */ -#define IsTransactionStmtPlan(plansource) \ - ((plansource)->raw_parse_tree == NULL || \ - IsA((plansource)->raw_parse_tree->stmt, TransactionStmt)) +#define StmtPlanRequiresRevalidation(plansource) \ + ((plansource)->raw_parse_tree != NULL && \ + stmt_requires_parse_analysis((plansource)->raw_parse_tree)) /* * This is the head of the backend's list of "saved" CachedPlanSources (i.e., @@ -381,13 +383,13 @@ CompleteCachedPlan(CachedPlanSource *plansource, plansource->query_context = querytree_context; plansource->query_list = querytree_list; - if (!plansource->is_oneshot && !IsTransactionStmtPlan(plansource)) + if (!plansource->is_oneshot && StmtPlanRequiresRevalidation(plansource)) { /* * 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.) We can skip this for one-shot plans, and - * transaction control commands have no such dependencies anyway. + * plans not needing revalidation have no such dependencies anyway. */ extract_query_dependencies((Node *) querytree_list, &plansource->relationOids, @@ -566,11 +568,11 @@ RevalidateCachedQuery(CachedPlanSource *plansource, /* * 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). + * so that no lock re-acquisition is necessary. Also, if the statement + * type can't require revalidation, we needn't do anything (and we mustn't + * risk catalog accesses when handling, eg, transaction control commands). */ - if (plansource->is_oneshot || IsTransactionStmtPlan(plansource)) + if (plansource->is_oneshot || !StmtPlanRequiresRevalidation(plansource)) { Assert(plansource->is_valid); return NIL; @@ -1026,8 +1028,8 @@ choose_custom_plan(CachedPlanSource *plansource, ParamListInfo boundParams) /* 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)) + /* ... nor when planning would be a no-op */ + if (!StmtPlanRequiresRevalidation(plansource)) return false; /* Let settings force the decision */ @@ -1778,8 +1780,8 @@ PlanCacheRelCallback(Datum arg, Oid relid) if (!plansource->is_valid) continue; - /* Never invalidate transaction control commands */ - if (IsTransactionStmtPlan(plansource)) + /* Never invalidate if parse/plan would be a no-op anyway */ + if (!StmtPlanRequiresRevalidation(plansource)) continue; /* @@ -1863,8 +1865,8 @@ PlanCacheObjectCallback(Datum arg, int cacheid, uint32 hashvalue) if (!plansource->is_valid) continue; - /* Never invalidate transaction control commands */ - if (IsTransactionStmtPlan(plansource)) + /* Never invalidate if parse/plan would be a no-op anyway */ + if (!StmtPlanRequiresRevalidation(plansource)) continue; /* @@ -1973,7 +1975,6 @@ ResetPlanCache(void) { CachedPlanSource *plansource = dlist_container(CachedPlanSource, node, iter.cur); - ListCell *lc; Assert(plansource->magic == CACHEDPLANSOURCE_MAGIC); @@ -1985,32 +1986,16 @@ ResetPlanCache(void) * 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). + * In general there's no point in invalidating statements for which a + * new parse analysis/rewrite/plan cycle would certainly give the same + * results. */ - if (IsTransactionStmtPlan(plansource)) + if (!StmtPlanRequiresRevalidation(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 = lfirst_node(Query, lc); - - 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; - } - } + plansource->is_valid = false; + if (plansource->gplan) + plansource->gplan->is_valid = false; } /* Likewise invalidate cached expressions */ |