Add pg_dist_local_group Metadata Table

This change adds the pg_dist_local_group metadata table, which indicates
the group id of the current node. It is expected that this table contains
one and only one row, which only contains the group id of the node as an
integer.

src/backend/distributed/Makefile

@@ -8,7 +8,7 @@ EXTENSION = citus
 EXTVERSIONS = 5.0 5.0-1 5.0-2  \
 	5.1-1 5.1-2 5.1-3 5.1-4 5.1-5 5.1-6 5.1-7 5.1-8 \
 	5.2-1 5.2-2 5.2-3 5.2-4 \
-	6.0-1 6.0-2 6.0-3 6.0-4 6.0-5 6.0-6 6.0-7 6.0-8
+	6.0-1 6.0-2 6.0-3 6.0-4 6.0-5 6.0-6 6.0-7 6.0-8 6.0-9
 
 # All citus--*.sql files in the source directory
 DATA = $(patsubst $(citus_abs_srcdir)/%.sql,%.sql,$(wildcard $(citus_abs_srcdir)/$(EXTENSION)--*--*.sql))
@@ -74,6 +74,8 @@ $(EXTENSION)--6.0-7.sql: $(EXTENSION)--6.0-6.sql $(EXTENSION)--6.0-6--6.0-7.sql
 	cat $^ > $@
 $(EXTENSION)--6.0-8.sql: $(EXTENSION)--6.0-7.sql $(EXTENSION)--6.0-7--6.0-8.sql
 	cat $^ > $@
+$(EXTENSION)--6.0-9.sql: $(EXTENSION)--6.0-8.sql $(EXTENSION)--6.0-8--6.0-9.sql
+	cat $^ > $@
 
 NO_PGXS = 1
 

src/backend/distributed/citus--6.0-4--6.0-5.sql

@@ -1,5 +1,3 @@
-/* citus--5.2-1--5.2-2.sql */
-
 /*
  * Replace oid column in pg_dist_shard_placement with an sequence column.
  */

src/backend/distributed/citus--6.0-6--6.0-7.sql

@@ -1,4 +1,4 @@
-/* citus--6.0-5--6.0-6.sql */
+/* citus--6.0-6--6.0-7.sql */
 
 CREATE FUNCTION pg_catalog.get_colocated_table_array(regclass)
     RETURNS regclass[]

src/backend/distributed/citus--6.0-8--6.0-9.sql

@@ -0,0 +1,9 @@
+CREATE TABLE citus.pg_dist_local_group(
+    groupid int NOT NULL PRIMARY KEY)
+;
+
+/* insert the default value for being the coordinator node */
+INSERT INTO citus.pg_dist_local_group VALUES (0);
+
+ALTER TABLE citus.pg_dist_local_group SET SCHEMA pg_catalog;
+GRANT SELECT ON pg_catalog.pg_dist_local_group TO public;

src/backend/distributed/citus.control

@@ -1,6 +1,6 @@
 # Citus extension
 comment = 'Citus distributed database'
-default_version = '6.0-8'
+default_version = '6.0-9'
 module_pathname = '$libdir/citus'
 relocatable = false
 schema = pg_catalog

src/test/regress/expected/multi_extension.out

@@ -34,6 +34,7 @@ ALTER EXTENSION citus UPDATE TO '6.0-5';
 ALTER EXTENSION citus UPDATE TO '6.0-6';
 ALTER EXTENSION citus UPDATE TO '6.0-7';
 ALTER EXTENSION citus UPDATE TO '6.0-8';
+ALTER EXTENSION citus UPDATE TO '6.0-9';
 -- drop extension an re-create in newest version
 DROP EXTENSION citus;
 \c

src/test/regress/sql/multi_extension.sql

@@ -39,6 +39,7 @@ ALTER EXTENSION citus UPDATE TO '6.0-5';
 ALTER EXTENSION citus UPDATE TO '6.0-6';
 ALTER EXTENSION citus UPDATE TO '6.0-7';
 ALTER EXTENSION citus UPDATE TO '6.0-8';
+ALTER EXTENSION citus UPDATE TO '6.0-9';
 
 -- drop extension an re-create in newest version
 DROP EXTENSION citus;