Update pg_buffercache extension for parallel query.

The pg_buffercache_pages function provided by this extension is
PARALLEL SAFE.

Andreas Karlsson

contrib/pg_buffercache/Makefile

@@ -4,7 +4,8 @@ MODULE_big = pg_buffercache
 OBJS = pg_buffercache_pages.o $(WIN32RES)
 
 EXTENSION = pg_buffercache
-DATA = pg_buffercache--1.1.sql pg_buffercache--1.0--1.1.sql pg_buffercache--unpackaged--1.0.sql
+DATA = pg_buffercache--1.2.sql pg_buffercache--1.1--1.2.sql \
+	pg_buffercache--1.0--1.1.sql pg_buffercache--unpackaged--1.0.sql
 PGFILEDESC = "pg_buffercache - monitoring of shared buffer cache in real-time"
 
 ifdef USE_PGXS

contrib/pg_buffercache/pg_buffercache--1.1--1.2.sql

+/* contrib/pg_buffercache/pg_buffercache--1.1--1.2.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_buffercache UPDATE TO '1.2'" to load this file. \quit
+
+ALTER FUNCTION pg_buffercache_pages() PARALLEL SAFE;

contrib/pg_buffercache/pg_buffercache--1.1.sql → contrib/pg_buffercache/pg_buffercache--1.2.sql

-/* contrib/pg_buffercache/pg_buffercache--1.1.sql */
+/* contrib/pg_buffercache/pg_buffercache--1.2.sql */
 
 -- complain if script is sourced in psql, rather than via CREATE EXTENSION
 \echo Use "CREATE EXTENSION pg_buffercache" to load this file. \quit
@@ -7,7 +7,7 @@
 CREATE FUNCTION pg_buffercache_pages()
 RETURNS SETOF RECORD
 AS 'MODULE_PATHNAME', 'pg_buffercache_pages'
-LANGUAGE C;
+LANGUAGE C PARALLEL SAFE;
 
 -- Create a view for convenient access.
 CREATE VIEW pg_buffercache AS

contrib/pg_buffercache/pg_buffercache.control

 # pg_buffercache extension
 comment = 'examine the shared buffer cache'
-default_version = '1.1'
+default_version = '1.2'
 module_pathname = '$libdir/pg_buffercache'
 relocatable = true