From 0083f645886eba3d9611b9430b30fcde458c3be7 Mon Sep 17 00:00:00 2001
From: marko <>
Date: Wed, 10 Dec 2008 15:20:17 +0000
Subject: [PATCH] branches/innodb+: When buffering an insert, notify the buffer
 pool watch.  This should fix the race condition that seems to have caused
 Issue #126: When another thread is buffering an insert for the record that is
 being purged, it should invoke buf_pool_watch_notify(), so that the purge
 will not be buffered. Otherwise, the purge would be buffered for the wrong
 record (one that was inserted after the purge determined that the record can
 be removed).

When deletes are not buffered, the latch on the secondary index page
would prevent the insert from occurring.  In delete buffering, the
buf_pool_watch replaces the page latch when the page is not in the
buffer pool.

buf_pool_watch_notify(): Make public.

ibuf_insert(): Invoke buf_pool_watch_notify() when buffering an
insert or a delete-mark operation.
---
 buf/buf0buf.c     |  8 ++++----
 ibuf/ibuf0ibuf.c  | 17 +++++++++++++++++
 include/buf0buf.h |  8 ++++++++
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/buf/buf0buf.c b/buf/buf0buf.c
index 4b4355033cb..acb9af524f9 100644
--- a/buf/buf0buf.c
+++ b/buf/buf0buf.c
@@ -2506,13 +2506,13 @@ buf_page_init_low(
 }
 
 /************************************************************************
-Set watch happened flag. */
-UNIV_INLINE
+Set watch occurred flag. */
+UNIV_INTERN
 void
 buf_pool_watch_notify(
 /*==================*/
-	ulint		space,	/* in: space id of page read in */
-	ulint		offset)	/* in: offset of page read in */
+	ulint	space,	/* in: space id of page read in */
+	ulint	offset)	/* in: offset of page read in */
 {
 	ut_ad(buf_pool_mutex_own());
 
diff --git a/ibuf/ibuf0ibuf.c b/ibuf/ibuf0ibuf.c
index 762e15daeb7..9afa1bb06d1 100644
--- a/ibuf/ibuf0ibuf.c
+++ b/ibuf/ibuf0ibuf.c
@@ -3462,6 +3462,23 @@ ibuf_insert(
 
 	ut_a(!dict_index_is_clust(index));
 
+	if (UNIV_LIKELY(op != IBUF_OP_DELETE)) {
+		/* If another thread buffers an insert on a page while
+		the purge is in progress, the purge for the same page
+		must not be buffered, because it could remove a record
+		that was re-inserted later.
+
+		We do not call this in the IBUF_OP_DELETE case,
+		because that would always trigger the buffer pool
+		watch during purge and thus prevent the buffering of
+		delete operations.  We assume that IBUF_OP_DELETE
+		operations are only issued by the purge thread. */
+
+		buf_pool_mutex_enter();
+		buf_pool_watch_notify(space, page_no);
+		buf_pool_mutex_exit();
+	}
+
 	entry_size = rec_get_converted_size(index, entry, 0);
 
 	if (entry_size >= (page_get_free_space_of_empty(comp) / 2)) {
diff --git a/include/buf0buf.h b/include/buf0buf.h
index c5701586619..09664bd2258 100644
--- a/include/buf0buf.h
+++ b/include/buf0buf.h
@@ -981,6 +981,14 @@ UNIV_INTERN
 void
 buf_pool_watch_clear(void);
 /*======================*/
+/************************************************************************
+Set watch occurred flag. */
+UNIV_INTERN
+void
+buf_pool_watch_notify(
+/*==================*/
+	ulint	space,	/* in: space id of page read in */
+	ulint	offset);/* in: offset of page read in */
 /********************************************************************
 Check if the given page is being watched and has been read to the buffer
 pool. */