Fix pg_upgrade to handle extensions.

This follows my proposal of yesterday, namely that we try to recreate the
previous state of the extension exactly, instead of allowing CREATE
EXTENSION to run a SQL script that might create some entirely-incompatible
on-disk state.  In --binary-upgrade mode, pg_dump won't issue CREATE
EXTENSION at all, but instead uses a kluge function provided by
pg_upgrade_support to recreate the pg_extension row (and extension-level
pg_depend entries) without creating any member objects.  The member objects
are then restored in the same way as if they weren't members, in particular
using pg_upgrade's normal hacks to preserve OIDs that need to be preserved.
Then, for each member object, ALTER EXTENSION ADD is issued to recreate the
pg_depend entry that marks it as an extension member.

In passing, fix breakage in pg_upgrade's enum-type support: somebody didn't
fix it when the noise word VALUE got added to ALTER TYPE ADD.  Also,
rationalize parsetree representation of COMMENT ON DOMAIN and fix
get_object_address() to allow OBJECT_DOMAIN.

1 files changed, 71 insertions, 2 deletions

diff --git a/contrib/pg_upgrade_support/pg_upgrade_support.c b/contrib/pg_upgrade_support/pg_upgrade_support.c
index b499ff80e6..8b0e474dce 100644
--- a/contrib/pg_upgrade_support/pg_upgrade_support.c
+++ b/contrib/pg_upgrade_support/pg_upgrade_support.c
@@ -1,8 +1,9 @@
 /*
- *	pg_upgrade_sysoids.c
+ *	pg_upgrade_support.c
  *
  *	server-side functions to set backend global variables
- *	to control oid and relfilenode assignment
+ *	to control oid and relfilenode assignment, and do other special
+ *	hacks needed for pg_upgrade.
  *
  *	Copyright (c) 2010-2011, PostgreSQL Global Development Group
  *	contrib/pg_upgrade_support/pg_upgrade_support.c
@@ -12,7 +13,13 @@
 
 #include "fmgr.h"
 #include "catalog/dependency.h"
+#include "catalog/namespace.h"
 #include "catalog/pg_class.h"
+#include "catalog/pg_type.h"
+#include "commands/extension.h"
+#include "miscadmin.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
 
 /* THIS IS USED ONLY FOR PG >= 9.0 */
 
@@ -42,6 +49,8 @@ Datum		set_next_toast_pg_class_oid(PG_FUNCTION_ARGS);
 Datum		set_next_pg_enum_oid(PG_FUNCTION_ARGS);
 Datum		set_next_pg_authid_oid(PG_FUNCTION_ARGS);
 
+Datum		create_empty_extension(PG_FUNCTION_ARGS);
+
 PG_FUNCTION_INFO_V1(set_next_pg_type_oid);
 PG_FUNCTION_INFO_V1(set_next_array_pg_type_oid);
 PG_FUNCTION_INFO_V1(set_next_toast_pg_type_oid);
@@ -53,6 +62,8 @@ PG_FUNCTION_INFO_V1(set_next_toast_pg_class_oid);
 PG_FUNCTION_INFO_V1(set_next_pg_enum_oid);
 PG_FUNCTION_INFO_V1(set_next_pg_authid_oid);
 
+PG_FUNCTION_INFO_V1(create_empty_extension);
+
 
 Datum
 set_next_pg_type_oid(PG_FUNCTION_ARGS)
@@ -133,3 +144,61 @@ set_next_pg_authid_oid(PG_FUNCTION_ARGS)
 	PG_RETURN_VOID();
 }
 
+Datum
+create_empty_extension(PG_FUNCTION_ARGS)
+{
+	text	   *extName = PG_GETARG_TEXT_PP(0);
+	text	   *schemaName = PG_GETARG_TEXT_PP(1);
+	bool		relocatable = PG_GETARG_BOOL(2);
+	char	   *extVersion;
+	Datum		extConfig;
+	Datum		extCondition;
+	List	   *requiredExtensions;
+
+	if (PG_ARGISNULL(3))
+		extVersion = NULL;
+	else
+		extVersion = text_to_cstring(PG_GETARG_TEXT_PP(3));
+
+	if (PG_ARGISNULL(4))
+		extConfig = PointerGetDatum(NULL);
+	else
+		extConfig = PG_GETARG_DATUM(4);
+
+	if (PG_ARGISNULL(5))
+		extCondition = PointerGetDatum(NULL);
+	else
+		extCondition = PG_GETARG_DATUM(5);
+
+	requiredExtensions = NIL;
+	if (!PG_ARGISNULL(6))
+	{
+		ArrayType  *textArray = PG_GETARG_ARRAYTYPE_P(6);
+		Datum	   *textDatums;
+		int			ndatums;
+		int			i;
+
+		deconstruct_array(textArray,
+						  TEXTOID, -1, false, 'i',
+						  &textDatums, NULL, &ndatums);
+		for (i = 0; i < ndatums; i++)
+		{
+			text   *txtname = DatumGetTextPP(textDatums[i]);
+			char   *extName = text_to_cstring(txtname);
+			Oid		extOid = get_extension_oid(extName, false);
+
+			requiredExtensions = lappend_oid(requiredExtensions, extOid);
+		}
+	}
+
+	InsertExtensionTuple(text_to_cstring(extName),
+						 GetUserId(),
+						 get_namespace_oid(text_to_cstring(schemaName), false),
+						 relocatable,
+						 extVersion,
+						 extConfig,
+						 extCondition,
+						 requiredExtensions);
+
+	PG_RETURN_VOID();
+}