Fix master_update_table_statistics scripts for 9.4

src/backend/distributed/sql/citus--9.4-2--9.4-3.sql

@@ -0,0 +1,7 @@
+-- 9.4-2--9.4-3 was added later as a patch to improve master_update_table_statistics
+CREATE OR REPLACE FUNCTION master_update_table_statistics(relation regclass)
+RETURNS VOID
+    LANGUAGE C STRICT
+    AS 'MODULE_PATHNAME', $$citus_update_table_statistics$$;
+COMMENT ON FUNCTION pg_catalog.master_update_table_statistics(regclass)
+	IS 'updates shard statistics of the given table';

src/backend/distributed/sql/citus--9.4-3--9.4-2.sql

@@ -0,0 +1,22 @@
+-- citus--9.4-3--9.4-2
+-- This is a downgrade path that will revert the changes made in citus--9.4-2--9.4-3.sql
+-- 9.4-2--9.4-3 was added later as a patch to improve master_update_table_statistics.
+-- We have this downgrade script so that we can continue from the main upgrade path
+-- when upgrading to later versions.
+CREATE OR REPLACE FUNCTION master_update_table_statistics(relation regclass)
+RETURNS VOID AS $$
+DECLARE
+	colocated_tables regclass[];
+BEGIN
+	SELECT get_colocated_table_array(relation) INTO colocated_tables;
+
+	PERFORM
+		master_update_shard_statistics(shardid)
+	FROM
+		pg_dist_shard
+	WHERE
+		logicalrelid = ANY (colocated_tables);
+END;
+$$ LANGUAGE 'plpgsql';
+COMMENT ON FUNCTION master_update_table_statistics(regclass)
+	IS 'updates shard statistics of the given table and its colocated tables';

src/test/regress/expected/multi_extension.out

@@ -413,6 +413,82 @@ SELECT * FROM multi_extension.print_extension_changes();
 ---------------------------------------------------------------------
 (0 rows)
 
+-- Test upgrade paths for backported improvement of master_update_table_statistics function
+ALTER EXTENSION citus UPDATE TO '9.4-3';
+-- should see the new source code with internal function citus_update_table_statistics
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+            prosrc
+---------------------------------------------------------------------
+ citus_update_table_statistics
+(1 row)
+
+ALTER EXTENSION citus UPDATE TO '9.4-2';
+-- should see the old source code
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+                               prosrc
+---------------------------------------------------------------------
+                                                                   +
+ DECLARE                                                           +
+  colocated_tables regclass[];                                     +
+ BEGIN                                                             +
+  SELECT get_colocated_table_array(relation) INTO colocated_tables;+
+  PERFORM                                                          +
+   master_update_shard_statistics(shardid)                         +
+  FROM                                                             +
+   pg_dist_shard                                                   +
+  WHERE                                                            +
+   logicalrelid = ANY (colocated_tables);                          +
+ END;                                                              +
+
+(1 row)
+
+-- Should be empty result
+SELECT * FROM multi_extension.print_extension_changes();
+ previous_object | current_object
+---------------------------------------------------------------------
+(0 rows)
+
+ALTER EXTENSION citus UPDATE TO '9.4-3';
+-- should see the new source code with internal function citus_update_table_statistics
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+            prosrc
+---------------------------------------------------------------------
+ citus_update_table_statistics
+(1 row)
+
+-- Should be empty result
+SELECT * FROM multi_extension.print_extension_changes();
+ previous_object | current_object
+---------------------------------------------------------------------
+(0 rows)
+
+-- Snapshot of state at 9.4-1
+ALTER EXTENSION citus UPDATE TO '9.4-1';
+-- should see the old source code
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+                               prosrc
+---------------------------------------------------------------------
+                                                                   +
+ DECLARE                                                           +
+  colocated_tables regclass[];                                     +
+ BEGIN                                                             +
+  SELECT get_colocated_table_array(relation) INTO colocated_tables;+
+  PERFORM                                                          +
+   master_update_shard_statistics(shardid)                         +
+  FROM                                                             +
+   pg_dist_shard                                                   +
+  WHERE                                                            +
+   logicalrelid = ANY (colocated_tables);                          +
+ END;                                                              +
+
+(1 row)
+
+-- Should be empty result
+SELECT * FROM multi_extension.print_extension_changes();
+ previous_object | current_object
+---------------------------------------------------------------------
+(0 rows)
+
 -- Test downgrade to 9.4-1 from 9.5-1
 ALTER EXTENSION citus UPDATE TO '9.5-1';
 BEGIN;

src/test/regress/sql/multi_extension.sql

@@ -184,6 +184,30 @@ SELECT * FROM multi_extension.print_extension_changes();
 ALTER EXTENSION citus UPDATE TO '9.4-1';
 SELECT * FROM multi_extension.print_extension_changes();
 
+-- Test upgrade paths for backported improvement of master_update_table_statistics function
+ALTER EXTENSION citus UPDATE TO '9.4-3';
+-- should see the new source code with internal function citus_update_table_statistics
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+ALTER EXTENSION citus UPDATE TO '9.4-2';
+
+-- should see the old source code
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+-- Should be empty result
+SELECT * FROM multi_extension.print_extension_changes();
+
+ALTER EXTENSION citus UPDATE TO '9.4-3';
+-- should see the new source code with internal function citus_update_table_statistics
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+-- Should be empty result
+SELECT * FROM multi_extension.print_extension_changes();
+
+-- Snapshot of state at 9.4-1
+ALTER EXTENSION citus UPDATE TO '9.4-1';
+-- should see the old source code
+SELECT prosrc FROM pg_proc WHERE proname = 'master_update_table_statistics' ORDER BY 1;
+-- Should be empty result
+SELECT * FROM multi_extension.print_extension_changes();
+
 -- Test downgrade to 9.4-1 from 9.5-1
 ALTER EXTENSION citus UPDATE TO '9.5-1';