pg_buffercache needs to be taught about relation forks, as Greg Stark

pointed out.

3 files changed, 22 insertions, 8 deletions

diff --git a/contrib/pg_buffercache/pg_buffercache.sql.in b/contrib/pg_buffercache/pg_buffercache.sql.in
index fdc2050cbd..3bbe672af7 100644
--- a/contrib/pg_buffercache/pg_buffercache.sql.in
+++ b/contrib/pg_buffercache/pg_buffercache.sql.in
@@ -13,7 +13,7 @@ LANGUAGE C;
 CREATE VIEW pg_buffercache AS
 	SELECT P.* FROM pg_buffercache_pages() AS P
  	(bufferid integer, relfilenode oid, reltablespace oid, reldatabase oid, 
- 	 relblocknumber int8, isdirty bool, usagecount int2);
+	 relforknumber int2, relblocknumber int8, isdirty bool, usagecount int2);
  
 -- Don't want these to be available at public.
 REVOKE ALL ON FUNCTION pg_buffercache_pages() FROM PUBLIC;
diff --git a/contrib/pg_buffercache/pg_buffercache_pages.c b/contrib/pg_buffercache/pg_buffercache_pages.c
index b1c3fbc324..34b9a8bf75 100644
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -16,7 +16,7 @@
 #include "utils/relcache.h"
 
 
-#define NUM_BUFFERCACHE_PAGES_ELEM	7
+#define NUM_BUFFERCACHE_PAGES_ELEM	8
 
 PG_MODULE_MAGIC;
 
@@ -32,6 +32,7 @@ typedef struct
 	Oid			relfilenode;
 	Oid			reltablespace;
 	Oid			reldatabase;
+	ForkNumber	forknum;
 	BlockNumber blocknum;
 	bool		isvalid;
 	bool		isdirty;
@@ -88,11 +89,13 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 						   OIDOID, -1, 0);
 		TupleDescInitEntry(tupledesc, (AttrNumber) 4, "reldatabase",
 						   OIDOID, -1, 0);
-		TupleDescInitEntry(tupledesc, (AttrNumber) 5, "relblocknumber",
+		TupleDescInitEntry(tupledesc, (AttrNumber) 5, "relforknumber",
+						   INT2OID, -1, 0);
+		TupleDescInitEntry(tupledesc, (AttrNumber) 6, "relblocknumber",
 						   INT8OID, -1, 0);
-		TupleDescInitEntry(tupledesc, (AttrNumber) 6, "isdirty",
+		TupleDescInitEntry(tupledesc, (AttrNumber) 7, "isdirty",
 						   BOOLOID, -1, 0);
-		TupleDescInitEntry(tupledesc, (AttrNumber) 7, "usage_count",
+		TupleDescInitEntry(tupledesc, (AttrNumber) 8, "usage_count",
 						   INT2OID, -1, 0);
 
 		fctx->tupdesc = BlessTupleDesc(tupledesc);
@@ -129,6 +132,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 			fctx->record[i].relfilenode = bufHdr->tag.rnode.relNode;
 			fctx->record[i].reltablespace = bufHdr->tag.rnode.spcNode;
 			fctx->record[i].reldatabase = bufHdr->tag.rnode.dbNode;
+			fctx->record[i].forknum = bufHdr->tag.forkNum;
 			fctx->record[i].blocknum = bufHdr->tag.blockNum;
 			fctx->record[i].usagecount = bufHdr->usage_count;
 
@@ -184,6 +188,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 			nulls[4] = true;
 			nulls[5] = true;
 			nulls[6] = true;
+			nulls[7] = true;
 		}
 		else
 		{
@@ -193,12 +198,14 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 			nulls[2] = false;
 			values[3] = ObjectIdGetDatum(fctx->record[i].reldatabase);
 			nulls[3] = false;
-			values[4] = Int64GetDatum((int64) fctx->record[i].blocknum);
+			values[4] = ObjectIdGetDatum(fctx->record[i].forknum);
 			nulls[4] = false;
-			values[5] = BoolGetDatum(fctx->record[i].isdirty);
+			values[5] = Int64GetDatum((int64) fctx->record[i].blocknum);
 			nulls[5] = false;
-			values[6] = Int16GetDatum(fctx->record[i].usagecount);
+			values[6] = BoolGetDatum(fctx->record[i].isdirty);
 			nulls[6] = false;
+			values[7] = Int16GetDatum(fctx->record[i].usagecount);
+			nulls[7] = false;
 		}
 
 		/* Build and return the tuple. */
diff --git a/doc/src/sgml/pgbuffercache.sgml b/doc/src/sgml/pgbuffercache.sgml
index d5416d492c..6f0d87279f 100644
--- a/doc/src/sgml/pgbuffercache.sgml
+++ b/doc/src/sgml/pgbuffercache.sgml
@@ -81,6 +81,13 @@
      </row>
 
      <row>
+      <entry><structfield>relforknumber</structfield></entry>
+      <entry><type>smallint</type></entry>
+      <entry></entry>
+      <entry>Fork number within the relation</entry>
+     </row>
+
+     <row>
       <entry><structfield>isdirty</structfield></entry>
       <entry><type>boolean</type></entry>
       <entry></entry>