pg_upgrade: prevent oid conflicts with new-cluster TOAST tables

Previously, TOAST tables only required in the new cluster could cause
oid conflicts if they were auto-numbered and a later conflicting oid had
to be assigned.

Backpatch through 9.3

2 files changed, 50 insertions, 10 deletions

diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index bdfeb90dd10..94543e1d510 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -165,16 +165,51 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 	if (rel->rd_rel->reltoastrelid != InvalidOid)
 		return false;
 
-	/*
-	 * Check to see whether the table actually needs a TOAST table.
-	 *
-	 * If an update-in-place toast relfilenode is specified, force toast file
-	 * creation even if it seems not to need one.
-	 */
-	if (!needs_toast_table(rel) &&
-		(!IsBinaryUpgrade ||
-		 !OidIsValid(binary_upgrade_next_toast_pg_class_oid)))
-		return false;
+	if (!IsBinaryUpgrade)
+	{
+		if (!needs_toast_table(rel))
+			return false;
+	}
+	else
+	{
+		/*
+		 * Check to see whether the table needs a TOAST table.
+		 *
+		 * If an update-in-place TOAST relfilenode is specified, force TOAST file
+		 * creation even if it seems not to need one.  This handles the case
+		 * where the old cluster needed a TOAST table but the new cluster
+		 * would not normally create one.
+		 */
+
+		/*
+		 * If a TOAST oid is not specified, skip TOAST creation as we will do
+		 * it later so we don't create a TOAST table whose OID later conflicts
+		 * with a user-supplied OID.  This handles cases where the old cluster
+		 * didn't need a TOAST table, but the new cluster does.
+		 */
+		if (!OidIsValid(binary_upgrade_next_toast_pg_class_oid))
+			return false;
+
+		/*
+		 * If a special TOAST value has been passed in, it means we are in
+		 * cleanup mode --- we are creating needed TOAST tables after all user
+		 * tables with specified OIDs have been created.  We let the system
+		 * assign a TOAST oid for us.  The tables are empty so the missing
+		 * TOAST tables were not a problem.
+		 */
+		if (binary_upgrade_next_toast_pg_class_oid == OPTIONALLY_CREATE_TOAST_OID)
+		{
+			/* clear as it is not to be used; it is just a flag */
+			binary_upgrade_next_toast_pg_class_oid = InvalidOid;
+
+			if (!needs_toast_table(rel))
+				return false;
+		}
+
+		/* both should be set, or not set */
+		Assert(OidIsValid(binary_upgrade_next_toast_pg_class_oid) ==
+			   OidIsValid(binary_upgrade_next_toast_pg_type_oid));
+	}
 
 	/*
 	 * If requested check lockmode is sufficient. This is a cross check in
diff --git a/src/include/catalog/binary_upgrade.h b/src/include/catalog/binary_upgrade.h
index f39017cfdf0..63fa85ed99e 100644
--- a/src/include/catalog/binary_upgrade.h
+++ b/src/include/catalog/binary_upgrade.h
@@ -14,6 +14,11 @@
 #ifndef BINARY_UPGRADE_H
 #define BINARY_UPGRADE_H
 
+#include "catalog/pg_authid.h"
+
+/* pick a OID that will never be used for TOAST tables */
+#define OPTIONALLY_CREATE_TOAST_OID	BOOTSTRAP_SUPERUSERID
+
 extern PGDLLIMPORT Oid binary_upgrade_next_pg_type_oid;
 extern PGDLLIMPORT Oid binary_upgrade_next_array_pg_type_oid;
 extern PGDLLIMPORT Oid binary_upgrade_next_toast_pg_type_oid;