pg_buffercache: Change page_num type to bigint

The page_num was defined as integer, which should be sufficient for the
near future (with 4K pages it's 8TB). But it's virtually free to return
bigint, and get a wider range. This was agreed on the thread, but I
forgot to tweak this in ba2a3c2.

While at it, make the data types in CREATE VIEW a bit more consistent.

Discussion: https://postgr.es/m/CAKZiRmxh6KWo0aqRqvmcoaX2jUxZYb4kGp3N%3Dq1w%2BDiH-696Xw%40mail.gmail.co

Author: tvondra

contrib/pg_buffercache/pg_buffercache--1.5--1.6.sql

@@ -12,7 +12,7 @@ LANGUAGE C PARALLEL SAFE;
 -- Create a view for convenient access.
 CREATE VIEW pg_buffercache_numa AS
 	SELECT P.* FROM pg_buffercache_numa_pages() AS P
-	(bufferid integer, os_page_num int4, numa_node int4);
+	(bufferid integer, os_page_num bigint, numa_node integer);
 
 -- Don't want these to be available to public.
 REVOKE ALL ON FUNCTION pg_buffercache_numa_pages() FROM PUBLIC;

contrib/pg_buffercache/pg_buffercache_pages.c

@@ -72,7 +72,7 @@ typedef struct
 typedef struct
 {
 	uint32		bufferid;
-	int32		page_num;
+	int64		page_num;
 	int32		numa_node;
 } BufferCacheNumaRec;
 
@@ -414,7 +414,7 @@ pg_buffercache_numa_pages(PG_FUNCTION_ARGS)
 		TupleDescInitEntry(tupledesc, (AttrNumber) 1, "bufferid",
 						   INT4OID, -1, 0);
 		TupleDescInitEntry(tupledesc, (AttrNumber) 2, "os_page_num",
-						   INT4OID, -1, 0);
+						   INT8OID, -1, 0);
 		TupleDescInitEntry(tupledesc, (AttrNumber) 3, "numa_node",
 						   INT4OID, -1, 0);
 
@@ -522,7 +522,7 @@ pg_buffercache_numa_pages(PG_FUNCTION_ARGS)
 		values[0] = Int32GetDatum(fctx->record[i].bufferid);
 		nulls[0] = false;
 
-		values[1] = Int32GetDatum(fctx->record[i].page_num);
+		values[1] = Int64GetDatum(fctx->record[i].page_num);
 		nulls[1] = false;
 
 		values[2] = Int32GetDatum(fctx->record[i].numa_node);

doc/src/sgml/pgbuffercache.sgml

@@ -267,7 +267,7 @@
 
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>os_page_num</structfield> <type>int</type>
+       <structfield>os_page_num</structfield> <type>bigint</type>
       </para>
       <para>
        number of OS memory page for this buffer