From 3d9e8db9e56beb0501d168779ae9644587924061 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 15 Sep 2015 11:08:56 -0400 Subject: [PATCH] Revert "Fix an O(N^2) problem in foreign key references". Commit 5ddc72887a012f6a8b85707ef27d85c274faf53d does not actually work because it will happily blow away ri_constraint_cache entries that are in active use in outer call levels. In any case, it's a very ugly, brute-force solution to the problem of limiting the cache size. Revert until it can be redesigned. --- src/backend/utils/adt/ri_triggers.c | 38 +++-------------------------- 1 file changed, 3 insertions(+), 35 deletions(-) diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c index 0469522a56..61edde9c5d 100644 --- a/src/backend/utils/adt/ri_triggers.c +++ b/src/backend/utils/adt/ri_triggers.c @@ -183,7 +183,6 @@ typedef struct RI_CompareHashEntry * ---------- */ static HTAB *ri_constraint_cache = NULL; -static long ri_constraint_cache_seq_count = 0; static HTAB *ri_query_cache = NULL; static HTAB *ri_compare_cache = NULL; @@ -216,7 +215,6 @@ static bool ri_KeysEqual(Relation rel, HeapTuple oldtup, HeapTuple newtup, static bool ri_AttributesEqual(Oid eq_opr, Oid typeid, Datum oldvalue, Datum newvalue); -static void ri_InitConstraintCache(void); static void ri_InitHashTables(void); static void InvalidateConstraintCacheCallBack(Datum arg, int cacheid, uint32 hashvalue); static SPIPlanPtr ri_FetchPreparedPlan(RI_QueryKey *key); @@ -2947,20 +2945,6 @@ InvalidateConstraintCacheCallBack(Datum arg, int cacheid, uint32 hashvalue) Assert(ri_constraint_cache != NULL); - /* - * Prevent an O(N^2) problem when creating large amounts of foreign - * key constraints with ALTER TABLE, like it happens at the end of - * a pg_dump with hundred-thousands of tables having references. - */ - ri_constraint_cache_seq_count += hash_get_num_entries(ri_constraint_cache); - if (ri_constraint_cache_seq_count > 1000000) - { - hash_destroy(ri_constraint_cache); - ri_InitConstraintCache(); - ri_constraint_cache_seq_count = 0; - return; - } - hash_seq_init(&status, ri_constraint_cache); while ((hentry = (RI_ConstraintInfo *) hash_seq_search(&status)) != NULL) { @@ -3380,15 +3364,13 @@ ri_NullCheck(HeapTuple tup, /* ---------- - * ri_InitConstraintCache - * - * Initialize ri_constraint_cache when new or being rebuilt. + * ri_InitHashTables - * - * This needs to be done from two places, so split it out to prevent drift. + * Initialize our internal hash tables. * ---------- */ static void -ri_InitConstraintCache(void) +ri_InitHashTables(void) { HASHCTL ctl; @@ -3398,20 +3380,6 @@ ri_InitConstraintCache(void) ri_constraint_cache = hash_create("RI constraint cache", RI_INIT_CONSTRAINTHASHSIZE, &ctl, HASH_ELEM | HASH_BLOBS); -} - -/* ---------- - * ri_InitHashTables - - * - * Initialize our internal hash tables. - * ---------- - */ -static void -ri_InitHashTables(void) -{ - HASHCTL ctl; - - ri_InitConstraintCache(); /* Arrange to flush cache on pg_constraint changes */ CacheRegisterSyscacheCallback(CONSTROID, -- 2.40.0