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.

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 0469522a567bb3e17752b192ded77a33d0bb442d..61edde9c5d35a4ccdae954d7e25329d208ab15e8 100644 (file)
--- 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,