Fix upgrade from 1.4 to 1.5.

This upgrade drops a column from pg_config. This is problematic, because
pg_attribute entry is never actually removed in Postgres and fresh install and
upgraded one had different number of attrs. To avoid bothering with this,
recreate pg_config during upgrade from scratch.

To test this, rewrite check_update.py which was outright broken; now it runs
large part of regression tests.

Also, test script revealed that update script hasn't included dd71813 fix for replace_hash_partition.

Author: arssher

pg_pathman--1.4--1.5.sql

@@ -11,6 +11,41 @@ RETURNS BOOL AS 'pg_pathman', 'validate_interval_value'
 LANGUAGE C;
 
 ALTER TABLE @extschema@.pathman_config DROP COLUMN cooked_expr;
+/*
+ * Dropped columns are never actually purged, entry in pg_attribute remains.
+ * Since dealing with different number of attrs in C code is cumbersome,
+ * let's recreate table instead.
+ */
+CREATE TABLE @extschema@.pathman_config_tmp (LIKE @extschema@.pathman_config INCLUDING ALL);
+INSERT INTO @extschema@.pathman_config_tmp SELECT * FROM @extschema@.pathman_config;
+ALTER EVENT TRIGGER pathman_ddl_trigger DISABLE;
+DROP TABLE @extschema@.pathman_config;
+ALTER TABLE @extschema@.pathman_config_tmp RENAME TO pathman_config;
+ALTER EVENT TRIGGER pathman_ddl_trigger ENABLE;
+
+/*
+ * Get back stuff not preserved by CREATE TABLE LIKE: ACL, RLS and
+ * pg_extension_config_dump mark.
+ */
+
+GRANT SELECT, INSERT, UPDATE, DELETE
+ON @extschema@.pathman_config
+TO public;
+
+/*
+ * Row security policy to restrict partitioning operations to owner and superusers only
+ */
+CREATE POLICY deny_modification ON @extschema@.pathman_config
+FOR ALL USING (check_security_policy(partrel));
+CREATE POLICY allow_select ON @extschema@.pathman_config FOR SELECT USING (true);
+ALTER TABLE @extschema@.pathman_config ENABLE ROW LEVEL SECURITY;
+
+/*
+ * Enable dump of config tables with pg_dump.
+ */
+SELECT pg_catalog.pg_extension_config_dump('@extschema@.pathman_config', '');
+
+
 ALTER TABLE @extschema@.pathman_config ADD CONSTRAINT pathman_config_interval_check
 	CHECK (@extschema@.validate_interval_value(partrel,
 											   expr,
@@ -505,6 +540,100 @@ BEGIN
 END
 $$ LANGUAGE plpgsql;
 
+/*
+ * Replace hash partition with another one. It could be useful in case when
+ * someone wants to attach foreign table as a partition.
+ *
+ * lock_parent - should we take an exclusive lock?
+ */
+CREATE OR REPLACE FUNCTION @extschema@.replace_hash_partition(
+	old_partition		REGCLASS,
+	new_partition		REGCLASS,
+	lock_parent			BOOL DEFAULT TRUE)
+RETURNS REGCLASS AS $$
+DECLARE
+	parent_relid		REGCLASS;
+	old_constr_name		TEXT;		/* name of old_partition's constraint */
+	old_constr_def		TEXT;		/* definition of old_partition's constraint */
+	rel_persistence		CHAR;
+	p_init_callback		REGPROCEDURE;
+
+BEGIN
+	PERFORM @extschema@.validate_relname(old_partition);
+	PERFORM @extschema@.validate_relname(new_partition);
+
+	/* Parent relation */
+	parent_relid := @extschema@.get_parent_of_partition(old_partition);
+
+	IF lock_parent THEN
+		/* Acquire data modification lock (prevent further modifications) */
+		PERFORM @extschema@.prevent_data_modification(parent_relid);
+	ELSE
+		/* Acquire lock on parent */
+		PERFORM @extschema@.prevent_part_modification(parent_relid);
+	END IF;
+
+	/* Acquire data modification lock (prevent further modifications) */
+	PERFORM @extschema@.prevent_data_modification(old_partition);
+	PERFORM @extschema@.prevent_data_modification(new_partition);
+
+	/* Ignore temporary tables */
+	SELECT relpersistence FROM pg_catalog.pg_class
+	WHERE oid = new_partition INTO rel_persistence;
+
+	IF rel_persistence = 't'::CHAR THEN
+		RAISE EXCEPTION 'temporary table "%" cannot be used as a partition',
+						new_partition::TEXT;
+	END IF;
+
+	/* Check that new partition has an equal structure as parent does */
+	IF NOT @extschema@.is_tuple_convertible(parent_relid, new_partition) THEN
+		RAISE EXCEPTION 'partition must have a compatible tuple format';
+	END IF;
+
+	/* Check that table is partitioned */
+	IF @extschema@.get_partition_key(parent_relid) IS NULL THEN
+		RAISE EXCEPTION 'table "%" is not partitioned', parent_relid::TEXT;
+	END IF;
+
+	/* Fetch name of old_partition's HASH constraint */
+	old_constr_name = @extschema@.build_check_constraint_name(old_partition::REGCLASS);
+
+	/* Fetch definition of old_partition's HASH constraint */
+	SELECT pg_catalog.pg_get_constraintdef(oid) FROM pg_catalog.pg_constraint
+	WHERE conrelid = old_partition AND quote_ident(conname) = old_constr_name
+	INTO old_constr_def;
+
+	/* Detach old partition */
+	EXECUTE format('ALTER TABLE %s NO INHERIT %s', old_partition, parent_relid);
+	EXECUTE format('ALTER TABLE %s DROP CONSTRAINT %s',
+				   old_partition,
+				   old_constr_name);
+
+	/* Attach the new one */
+	EXECUTE format('ALTER TABLE %s INHERIT %s', new_partition, parent_relid);
+	EXECUTE format('ALTER TABLE %s ADD CONSTRAINT %s %s',
+				   new_partition,
+				   @extschema@.build_check_constraint_name(new_partition::REGCLASS),
+				   old_constr_def);
+
+	/* Fetch init_callback from 'params' table */
+	WITH stub_callback(stub) as (values (0))
+	SELECT init_callback
+	FROM stub_callback
+	LEFT JOIN @extschema@.pathman_config_params AS params
+	ON params.partrel = parent_relid
+	INTO p_init_callback;
+
+	/* Finally invoke init_callback */
+	PERFORM @extschema@.invoke_on_partition_created_callback(parent_relid,
+															 new_partition,
+															 p_init_callback);
+
+	RETURN new_partition;
+END
+$$ LANGUAGE plpgsql;
+
 /*
  * Disable pathman partitioning for specified relation.
  */

tests/update/README.md

@@ -9,3 +9,9 @@ PG_CONFIG=... ./dump_pathman_objects %DBNAME%
 
 diff file_1 file_2
 ```
+
+check_update.py script tries to verify that update is ok automatically. For
+instance,
+```bash
+tests/update/check_update.py d34a77e worktree
+```