Repair problems with the result of lookup_rowtype_tupdesc() possibly being

discarded by cache flush while still in use.  This is a minimal patch that
just copies the tupdesc anywhere it could be needed across a flush.  Applied
to back branches only; Neil Conway is working on a better long-term solution
for HEAD.

4 files changed, 18 insertions, 7 deletions

diff --git a/src/backend/utils/adt/rowtypes.c b/src/backend/utils/adt/rowtypes.c
index 1a12185b048..04756db10c8 100644
--- a/src/backend/utils/adt/rowtypes.c
+++ b/src/backend/utils/adt/rowtypes.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/rowtypes.c,v 1.13 2005/10/15 02:49:29 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/rowtypes.c,v 1.13.2.1 2006/01/17 17:33:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -83,6 +83,7 @@ record_in(PG_FUNCTION_ARGS)
 		   errmsg("input of anonymous composite types is not implemented")));
 	tupTypmod = -1;				/* for all non-anonymous types */
 	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
+	tupdesc = CreateTupleDescCopy(tupdesc);
 	ncolumns = tupdesc->natts;
 
 	/*
@@ -261,6 +262,7 @@ record_in(PG_FUNCTION_ARGS)
 	pfree(buf.data);
 	pfree(values);
 	pfree(nulls);
+	FreeTupleDesc(tupdesc);
 
 	PG_RETURN_HEAPTUPLEHEADER(result);
 }
@@ -288,6 +290,7 @@ record_out(PG_FUNCTION_ARGS)
 	tupType = HeapTupleHeaderGetTypeId(rec);
 	tupTypmod = HeapTupleHeaderGetTypMod(rec);
 	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
+	tupdesc = CreateTupleDescCopy(tupdesc);
 	ncolumns = tupdesc->natts;
 
 	/* Build a temporary HeapTuple control structure */
@@ -409,6 +412,7 @@ record_out(PG_FUNCTION_ARGS)
 
 	pfree(values);
 	pfree(nulls);
+	FreeTupleDesc(tupdesc);
 
 	PG_RETURN_CSTRING(buf.data);
 }
@@ -449,6 +453,7 @@ record_recv(PG_FUNCTION_ARGS)
 		   errmsg("input of anonymous composite types is not implemented")));
 	tupTypmod = -1;				/* for all non-anonymous types */
 	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
+	tupdesc = CreateTupleDescCopy(tupdesc);
 	ncolumns = tupdesc->natts;
 
 	/*
@@ -597,6 +602,7 @@ record_recv(PG_FUNCTION_ARGS)
 	heap_freetuple(tuple);
 	pfree(values);
 	pfree(nulls);
+	FreeTupleDesc(tupdesc);
 
 	PG_RETURN_HEAPTUPLEHEADER(result);
 }
@@ -624,6 +630,7 @@ record_send(PG_FUNCTION_ARGS)
 	tupType = HeapTupleHeaderGetTypeId(rec);
 	tupTypmod = HeapTupleHeaderGetTypMod(rec);
 	tupdesc = lookup_rowtype_tupdesc(tupType, tupTypmod);
+	tupdesc = CreateTupleDescCopy(tupdesc);
 	ncolumns = tupdesc->natts;
 
 	/* Build a temporary HeapTuple control structure */
@@ -724,6 +731,7 @@ record_send(PG_FUNCTION_ARGS)
 
 	pfree(values);
 	pfree(nulls);
+	FreeTupleDesc(tupdesc);
 
 	PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
 }
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 3e6e2ffac47..82830223999 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -3,7 +3,7 @@
  *				back to source text
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.207.2.3 2005/12/30 18:34:27 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.207.2.4 2006/01/17 17:33:21 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -2699,7 +2699,7 @@ get_name_for_var_field(Var *var, int fieldno,
 
 	/* Got the tupdesc, so we can extract the field name */
 	Assert(fieldno >= 1 && fieldno <= tupleDesc->natts);
-	return NameStr(tupleDesc->attrs[fieldno - 1]->attname);
+	return pstrdup(NameStr(tupleDesc->attrs[fieldno - 1]->attname));
 }
 
 
@@ -3493,6 +3493,7 @@ get_rule_expr(Node *node, deparse_context *context,
 				if (rowexpr->row_typeid != RECORDOID)
 				{
 					tupdesc = lookup_rowtype_tupdesc(rowexpr->row_typeid, -1);
+					tupdesc = CreateTupleDescCopy(tupdesc);
 					Assert(list_length(rowexpr->args) <= tupdesc->natts);
 				}
 
diff --git a/src/backend/utils/cache/typcache.c b/src/backend/utils/cache/typcache.c
index b681892ca9e..16025e2c6ff 100644
--- a/src/backend/utils/cache/typcache.c
+++ b/src/backend/utils/cache/typcache.c
@@ -36,7 +36,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/typcache.c,v 1.15.2.1 2005/11/22 18:23:23 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/typcache.c,v 1.15.2.2 2006/01/17 17:33:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -377,6 +377,8 @@ lookup_default_opclass(Oid type_id, Oid am_id)
  *
  * Note: returned TupleDesc points to cached copy; caller must copy it
  * if intending to scribble on it or keep a reference for a long time.
+ * ("A long time" basically means "across any possible cache flush",
+ * which typically could occur at any relation open or catalog lookup.)
  */
 TupleDesc
 lookup_rowtype_tupdesc(Oid type_id, int32 typmod)
diff --git a/src/backend/utils/fmgr/funcapi.c b/src/backend/utils/fmgr/funcapi.c
index 0a51f7ae0f2..565eb111027 100644
--- a/src/backend/utils/fmgr/funcapi.c
+++ b/src/backend/utils/fmgr/funcapi.c
@@ -7,7 +7,7 @@
  * Copyright (c) 2002-2005, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/fmgr/funcapi.c,v 1.26 2005/10/15 02:49:32 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/fmgr/funcapi.c,v 1.26.2.1 2006/01/17 17:33:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -246,7 +246,7 @@ get_expr_result_type(Node *expr,
 			*resultTupleDesc = NULL;
 		result = get_type_func_class(typid);
 		if (result == TYPEFUNC_COMPOSITE && resultTupleDesc)
-			*resultTupleDesc = lookup_rowtype_tupdesc(typid, -1);
+			*resultTupleDesc = CreateTupleDescCopy(lookup_rowtype_tupdesc(typid, -1));
 	}
 
 	return result;
@@ -363,7 +363,7 @@ internal_get_result_type(Oid funcid,
 	{
 		case TYPEFUNC_COMPOSITE:
 			if (resultTupleDesc)
-				*resultTupleDesc = lookup_rowtype_tupdesc(rettype, -1);
+				*resultTupleDesc = CreateTupleDescCopy(lookup_rowtype_tupdesc(rettype, -1));
 			/* Named composite types can't have any polymorphic columns */
 			break;
 		case TYPEFUNC_SCALAR: