Add the usage count statistics to the information available in

contrib/pgbuffercache.

Greg Smith

diff --git a/contrib/pg_buffercache/README.pg_buffercache b/contrib/pg_buffercache/README.pg_buffercache
index 5fbfbe13c07f8b59c2556735a3094cf2f59994a0..5be9af8ce412b8a24992028435cbba8e48a9ef25 100644 (file)
--- a/contrib/pg_buffercache/README.pg_buffercache
+++ b/contrib/pg_buffercache/README.pg_buffercache
@@ -40,7 +40,7 @@ Notes
    reldatabase    | pg_database.oid      | Database for the relation.
    relblocknumber |                      | Offset of the page in the relation.
    isdirty        |                      | Is the page dirty?
-
+   usagecount     |                      | Page LRU count
 
   There is one row for each buffer in the shared cache. Unused buffers are
   shown with all fields null except bufferid.
@@ -60,20 +60,22 @@ Sample output
 
   regression=# \d pg_buffercache;
        View "public.pg_buffercache"
-       Column     |  Type   | Modifiers
-  ----------------+---------+-----------
-   bufferid       | integer |
-   relfilenode    | oid     |
-   reltablespace  | oid     |
-   reldatabase    | oid     |
-   relblocknumber | bigint  |
-   isdirty        | boolean |
+       Column     |  Type    | Modifiers
+  ----------------+----------+-----------
+   bufferid       | integer  |
+   relfilenode    | oid      |
+   reltablespace  | oid      |
+   reldatabase    | oid      |
+   relblocknumber | bigint   |
+   isdirty        | boolean  |
+   usagecount     | smallint |
+
   View definition:
    SELECT p.bufferid, p.relfilenode, p.reltablespace, p.reldatabase, 
-          p.relblocknumber, p.isdirty
+          p.relblocknumber, p.isdirty, p.usagecount
      FROM pg_buffercache_pages() p(bufferid integer, relfilenode oid, 
      reltablespace oid, reldatabase oid, relblocknumber bigint, 
-     isdirty boolean);
+     isdirty boolean, usagecount smallint);
 
   regression=# SELECT c.relname, count(*) AS buffers
                FROM pg_class c INNER JOIN pg_buffercache b

diff --git a/contrib/pg_buffercache/pg_buffercache.sql.in b/contrib/pg_buffercache/pg_buffercache.sql.in
index ea63234f6b8a629c8065025af1d1857f2d9a1536..a96b5d91f65bcc4cfa37bf387762ab2020231529 100644 (file)
--- a/contrib/pg_buffercache/pg_buffercache.sql.in
+++ b/contrib/pg_buffercache/pg_buffercache.sql.in
@@ -12,7 +12,7 @@ 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);
+        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 ed7b6f60dd8495bcc747b8133dd197cb7de4f4ff..991c3db8e251daba873a451ec594361b48f3e943 100644 (file)
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -3,7 +3,7 @@
  * pg_buffercache_pages.c
  *       display some contents of the buffer cache
  *
- *       $PostgreSQL: pgsql/contrib/pg_buffercache/pg_buffercache_pages.c,v 1.11 2006/10/22 17:49:21 tgl Exp $
+ *       $PostgreSQL: pgsql/contrib/pg_buffercache/pg_buffercache_pages.c,v 1.12 2007/04/07 16:09:14 momjian Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -16,7 +16,7 @@
 #include "utils/relcache.h"
 
 
-#define NUM_BUFFERCACHE_PAGES_ELEM     6
+#define NUM_BUFFERCACHE_PAGES_ELEM     7
 
 PG_MODULE_MAGIC;
 
@@ -35,6 +35,7 @@ typedef struct
        BlockNumber blocknum;
        bool            isvalid;
        bool            isdirty;
+       uint16          usagecount;
 }      BufferCachePagesRec;
 
 
@@ -91,6 +92,8 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
                                                   INT8OID, -1, 0);
                TupleDescInitEntry(tupledesc, (AttrNumber) 6, "isdirty",
                                                   BOOLOID, -1, 0);
+               TupleDescInitEntry(tupledesc, (AttrNumber) 7, "usage_count",
+                                                  INT2OID, -1, 0);
 
                fctx->tupdesc = BlessTupleDesc(tupledesc);
 
@@ -126,6 +129,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
                        fctx->record[i].reltablespace = bufHdr->tag.rnode.spcNode;
                        fctx->record[i].reldatabase = bufHdr->tag.rnode.dbNode;
                        fctx->record[i].blocknum = bufHdr->tag.blockNum;
+                       fctx->record[i].usagecount = bufHdr->usage_count;
 
                        if (bufHdr->flags & BM_DIRTY)
                                fctx->record[i].isdirty = true;
@@ -172,6 +176,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
                        nulls[3] = true;
                        nulls[4] = true;
                        nulls[5] = true;
+                       nulls[6] = true;
                }
                else
                {
@@ -185,6 +190,8 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
                        nulls[4] = false;
                        values[5] = BoolGetDatum(fctx->record[i].isdirty);
                        nulls[5] = false;
+                       values[6] = Int16GetDatum(fctx->record[i].usagecount);
+                       nulls[6] = false;
                }
 
                /* Build and return the tuple. */