0004-Add-a-Hook-to-handle-OSCache-stats.patch

From 5a024cbbc3261454c49d8a77afd121605abc3390 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Villemain?= <cedric@2ndquadrant.fr>
Date: Thu, 26 May 2011 00:46:03 +0200
Subject: [PATCH 4/7] Add a Hook to handle OSCache stats

The hook is in RelationGetRelationOSCacheInFork
---
 src/backend/storage/buffer/bufmgr.c |    9 +++++++++
 src/include/storage/bufmgr.h        |    7 +++++++
 src/tools/pgindent/typedefs.list    |    1 +
 3 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
new file mode 100644
index 670dbdf..9bfa78c
*** a/src/backend/storage/buffer/bufmgr.c
--- b/src/backend/storage/buffer/bufmgr.c
*************** static volatile BufferDesc *BufferAlloc(
*** 106,111 ****
--- 106,116 ----
  static void FlushBuffer(volatile BufferDesc *buf, SMgrRelation reln);
  static void AtProcExit_Buffers(int code, Datum arg);
  
+ /*
+  * Hooks for plugin to get control in
+  * RelationGetRelationOSCacheInFork
+  */
+ oscache_hook_type OSCache_hook = NULL;
  
  /*
   * PrefetchBuffer -- initiate asynchronous read of a block of a relation
*************** RelationGetRelationOSCacheInFork(Relatio
*** 1938,1943 ****
--- 1943,1952 ----
  {
  	float4 percent = 0;
  
+ 	/* if a plugin is present, let it manage things */
+ 	if (OSCache_hook)
+ 		percent = (*OSCache_hook) (relation, forkNum);
+ 
  	return percent;
  }
  
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
new file mode 100644
index 7d22b5a..3098275
*** a/src/include/storage/bufmgr.h
--- b/src/include/storage/bufmgr.h
*************** extern void AtProcExit_LocalBuffers(void
*** 217,220 ****
--- 217,227 ----
  extern BufferAccessStrategy GetAccessStrategy(BufferAccessStrategyType btype);
  extern void FreeAccessStrategy(BufferAccessStrategy strategy);
  
+ /*
+ * Hooks for plugin to get control in
+ * RelationGetRelationOSCacheInFork
+ */
+ typedef float4 (*oscache_hook_type) (Relation relation, ForkNumber forkNum);
+ extern PGDLLIMPORT oscache_hook_type OSCache_hook;
+ 
  #endif
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
new file mode 100644
index f2982cd..a1bf8fe
*** a/src/tools/pgindent/typedefs.list
--- b/src/tools/pgindent/typedefs.list
*************** OprCacheKey
*** 963,968 ****
--- 963,969 ----
  OprInfo
  OprProofCacheEntry
  OprProofCacheKey
+ OSCache_hook_type
  OutputContext
  OverrideSearchPath
  OverrideStackEntry
-- 
1.7.5.3