Generalize concept of temporary relations to "relation persistence".

This commit replaces pg_class.relistemp with pg_class.relpersistence;
and also modifies the RangeVar node type to carry relpersistence rather
than istemp.  It also removes removes rd_istemp from RelationData and
instead performs the correct computation based on relpersistence.

For clarity, we add three new macros: RelationNeedsWAL(),
RelationUsesLocalBuffers(), and RelationUsesTempNamespace(), so that we
can clarify the purpose of each check that previous depended on
rd_istemp.

This is intended as infrastructure for the upcoming unlogged tables
patch, as well as for future possible work on global temporary tables.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index a8aee204c74..aa7c144c941 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -158,10 +158,11 @@ transformCreateStmt(CreateStmt *stmt, const char *queryString)
 	 * If the target relation name isn't schema-qualified, make it so.  This
 	 * prevents some corner cases in which added-on rewritten commands might
 	 * think they should apply to other relations that have the same name and
-	 * are earlier in the search path.	"istemp" is equivalent to a
-	 * specification of pg_temp, so no need for anything extra in that case.
+	 * are earlier in the search path.	But a local temp table is effectively
+	 * specified to be in pg_temp, so no need for anything extra in that case.
 	 */
-	if (stmt->relation->schemaname == NULL && !stmt->relation->istemp)
+	if (stmt->relation->schemaname == NULL
+		&& stmt->relation->relpersistence != RELPERSISTENCE_TEMP)
 	{
 		Oid			namespaceid = RangeVarGetCreationNamespace(stmt->relation);