RI triggers would fail for datatypes using old-style equal function,

because cached fmgr info contained reference to a shorter-lived data
structure.  Also guard against possibility that fmgr_info could fail,
leaving an incomplete entry present in the hash table.

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 71c1ccd4549a9259fc46408897908df785adc187..dc5f7c8495d44a6dfe9903a47b7039a609f0c910 100644 (file)
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -18,7 +18,7 @@
  * Portions Copyright (c) 2000-2001, PostgreSQL Global Development Group
  * Copyright 1999 Jan Wieck
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.24 2001/05/07 19:57:24 petere Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.25 2001/05/31 17:32:33 tgl Exp $
  *
  * ----------
  */
@@ -3243,7 +3243,9 @@ ri_AttributesEqual(Oid typeid, Datum oldvalue, Datum newvalue)
    if (!found)
    {
        HeapTuple   opr_tup;
-       Form_pg_operator opr_struct;
+       Oid         opr_proc;
+       MemoryContext   oldcontext;
+       FmgrInfo    finfo;
 
        opr_tup = SearchSysCache(OPERNAME,
                                 PointerGetDatum("="),
@@ -3251,9 +3253,22 @@ ri_AttributesEqual(Oid typeid, Datum oldvalue, Datum newvalue)
                                 ObjectIdGetDatum(typeid),
                                 CharGetDatum('b'));
        if (!HeapTupleIsValid(opr_tup))
-           elog(ERROR, "ri_AttributesEqual(): cannot find '=' operator "
-                "for type %u", typeid);
-       opr_struct = (Form_pg_operator) GETSTRUCT(opr_tup);
+           elog(ERROR,
+                "ri_AttributesEqual(): cannot find '=' operator for type %u",
+                typeid);
+       opr_proc = ((Form_pg_operator) GETSTRUCT(opr_tup))->oprcode;
+       ReleaseSysCache(opr_tup);
+
+       /*
+        * Since fmgr_info could fail, call it *before* creating the
+        * hashtable entry --- otherwise we could elog leaving an incomplete
+        * entry in the hashtable.  Also, because this will be a permanent
+        * table entry, we must make sure any subsidiary structures of the
+        * fmgr record are kept in TopMemoryContext.
+        */
+       oldcontext = MemoryContextSwitchTo(TopMemoryContext);
+       fmgr_info(opr_proc, &finfo);
+       MemoryContextSwitchTo(oldcontext);
 
        entry = (RI_OpreqHashEntry *) hash_search(ri_opreq_cache,
                                                  (char *) &typeid,
@@ -3263,8 +3278,7 @@ ri_AttributesEqual(Oid typeid, Datum oldvalue, Datum newvalue)
            elog(FATAL, "can't insert into RI operator cache");
 
        entry->typeid = typeid;
-       fmgr_info(opr_struct->oprcode, &(entry->oprfmgrinfo));
-       ReleaseSysCache(opr_tup);
+       memcpy(&(entry->oprfmgrinfo), &finfo, sizeof(FmgrInfo));
    }
 
    /*