branches/zip rb://138 (REVERT)

Revert the flush neighbors patch as it shows regression in
the benchmarks run by Michael.

ChangeLog

@@ -16,18 +16,6 @@
 	innodb_adaptive_flushing to control whether the new flushing
 	algorithm should be used.
 
-2009-07-07	The InnoDB Team
-
-	* buf/buf0flu.c:
-	Change the algorithm of flushing neighbors. The current
-	implementation is to try to flush the neighbors of every
-	page that we flush. This patch makes the following distinction:
-	  1) If the flush is from flush_list, AND
-	  2) If the flush is intended to move the oldest modification
-	     LSN ahead
-	THEN, do not try to flush the neighbors. Just focus on flushing
-	dirty pages at the end of flush_list.
-
 2009-07-07	The InnoDB Team
 
 	* srv/srv0srv.c, handler/ha_innodb.cc, log/log0log.c,

buf/buf0flu.c

@@ -1012,7 +1012,6 @@ buf_flush_batch(
 	ulint		old_page_count;
 	ulint		space;
 	ulint		offset;
-	ibool		try_neighbors = TRUE;
 
 	ut_ad((flush_type == BUF_FLUSH_LRU)
 	      || (flush_type == BUF_FLUSH_LIST));
@@ -1020,17 +1019,6 @@ buf_flush_batch(
 	ut_ad((flush_type != BUF_FLUSH_LIST)
 	      || sync_thread_levels_empty_gen(TRUE));
 #endif /* UNIV_SYNC_DEBUG */
-
-	/* If we are being asked to do a BUF_FLUSH_LIST flush and
-	min_n is ULINT_MAX and lsn_limit is provided then we are doing
-	this flush from within a query thread i.e.: not in background
-	and therefore we should not try to flush the neighbors and just
-	focus on getting the flushed LSN to the lsn_limit. */
-	if (flush_type == BUF_FLUSH_LIST && min_n == ULINT_MAX
-	    && lsn_limit != IB_ULONGLONG_MAX) {
-		try_neighbors = FALSE;
-	}
-
 	buf_pool_mutex_enter();
 
 	if ((buf_pool->n_flush[flush_type] > 0)
@@ -1090,37 +1078,19 @@ flush_next:
 			if (ready) {
 				space = buf_page_get_space(bpage);
 				offset = buf_page_get_page_no(bpage);
-				old_page_count = page_count;
-
-				if (try_neighbors) {
 
 				buf_pool_mutex_exit();
 
-					/* Try to flush also all the
-					neighbors */
+				old_page_count = page_count;
+
+				/* Try to flush also all the neighbors */
 				page_count += buf_flush_try_neighbors(
 					space, offset, flush_type);
 				/* fprintf(stderr,
-					"Flush type %lu, page no %lu,"
-					" neighb %lu\n",
+				"Flush type %lu, page no %lu, neighb %lu\n",
 				flush_type, offset,
 				page_count - old_page_count); */
 
-				} else {
-
-					/* Just flush this page. */
-					mutex_enter(block_mutex);
-
-					ut_a(buf_page_in_file(bpage));
-					ut_ad(bpage->in_page_hash);
-
-					/* buf_pool and block mutexes are
-					released inside the following
-					function. */
-					buf_flush_page(bpage, flush_type);
-					++page_count;
-				}
-
 				buf_pool_mutex_enter();
 				goto flush_next;