Merge lp:~sergei.glushchenko/percona-server/5.6-ps-bug1193319 into lp:percona-server/5.6

[Sergei Glushchenko]

     Bug 1193319: Failing assertion: ++count < 50 in file log0log.cc line 308

     * Move check of log tracking margin below archiving margin, which
       is equivalent of the following:

       if (either margin violated) {
         if (archiving margin violated) {
           archive;
         } else {
           sleep;
         }
         goto loop;
       }

     * Allocate separate count for tracking margin as it insert of
       large BLOB without doing checkpoints makes count spin too fast
       because log tracking margin will always be violated and the
       only possible way to proceed is to proceed further no matter of
       log tracking margin. This is not the case anymore.

     Both changes together make visible effect and assertion is harder
     to violate without changing the idea of assertion.

http://jenkins.percona.com/view/PS%205.6/job/percona-server-5.6-param/401/

[Vlad Lesin (vlad-lesin)]

review: Approve (g2)

[Laurynas Biveinis (laurynas-biveinis)]

Reset to Needs Review because G1 review was requested originally

[Laurynas Biveinis (laurynas-biveinis)]

review: Approve

=== modified file 'Percona-Server/storage/innobase/log/log0log.cc'
--- Percona-Server/storage/innobase/log/log0log.cc	2013-10-20 08:11:22 +0000
+++ Percona-Server/storage/innobase/log/log0log.cc	2013-11-03 10:02:30 +0000
@@ -251,6 +251,7 @@
 	ulint	dummy;
 #endif /* UNIV_LOG_ARCHIVE */
 	ulint	count			= 0;
+	ulint	tcount			= 0;
 
 	ut_a(len < log->buf_size / 2);
 loop:
@@ -279,21 +280,6 @@
 		goto loop;
 	}
 
-	if (log_check_tracking_margin(len_upper_limit) && (++count < 50)) {
-
-		/* This log write would violate the untracked LSN free space
-		margin.  Limit this to 50 retries as there might be situations
-		where we have no choice but to proceed anyway, i.e. if the log
-		is about to be overflown, log tracking or not. */
-		mutex_exit(&(log->mutex));
-
-		os_thread_sleep(10000);
-
-		mutex_enter(&(log->mutex));
-
-		goto loop;
-	}
-
 #ifdef UNIV_LOG_ARCHIVE
 	if (log->archiving_state != LOG_ARCH_OFF) {
 
@@ -318,6 +304,22 @@
 	}
 #endif /* UNIV_LOG_ARCHIVE */
 
+	if (log_check_tracking_margin(len_upper_limit) &&
+		(++tcount + count < 50)) {
+
+		/* This log write would violate the untracked LSN free space
+		margin.  Limit this to 50 retries as there might be situations
+		where we have no choice but to proceed anyway, i.e. if the log
+		is about to be overflown, log tracking or not. */
+		mutex_exit(&(log->mutex));
+
+		os_thread_sleep(10000);
+
+		mutex_enter(&(log->mutex));
+
+		goto loop;
+	}
+
 #ifdef UNIV_LOG_DEBUG
 	log->old_buf_free = log->buf_free;
 	log->old_lsn = log->lsn;