Merge lp:~akopytov/percona-xtrabackup/bug1097158-2.1 into lp:percona-xtrabackup/2.1

[Alexey Kopytov]

  Bug #1097158: xb_log_overwrap fails sporadically in Jenkin

  The test case tries to generate enough log writes to cause the log files
  wrap around and make xtrabackup fail with an error.

  Found 2 potential problems:

  - the test used the default log buffer size. Which, for an InnoDB
    plugin's default 8M buffer size, means there may be not enough changes
    in the on-disk files to trigger the expected error
  - the test suspended the main xtrabackup thread, but not the log copying
    thread. Which means the log copying thread could be catching up in the
    background and avoid reading wrapped-around log entries, and thus, the
    expected error.

  Fixed by setting an explicit log buffer size to the minimum value (1M)
  and using debug sync to suspend log copying thread, rather than the main
  one.

http://jenkins.percona.com/view/XtraBackup/job/percona-xtrabackup-2.1-param/141/

[Stewart Smith (stewart)]

review: Approve

=== modified file 'src/xtrabackup.c'
--- src/xtrabackup.c	2012-11-21 13:51:49 +0000
+++ src/xtrabackup.c	2013-01-08 11:36:03 +0000
@@ -1923,6 +1923,9 @@
 
 		/* innodb_mirrored_log_groups must be 1, no other groups */
 		ut_a(group == NULL);
+
+		debug_sync_point("xtrabackup_copy_logfile_pause");
+
 	}
 
 

=== modified file 'test/t/xb_log_overwrap.sh'
--- test/t/xb_log_overwrap.sh	2012-06-05 12:35:33 +0000
+++ test/t/xb_log_overwrap.sh	2013-01-08 11:36:03 +0000
@@ -1,38 +1,45 @@
 . inc/common.sh
 
-start_server --innodb_log_file_size=1M --innodb_thread_concurrency=1
+if ! $XB_BIN --help 2>&1 | grep -q debug-sync; then
+    echo "Requires --debug-sync support" > $SKIPPED_REASON
+    exit $SKIPPED_EXIT_CODE
+fi
+
+start_server --innodb_log_file_size=1M --innodb_thread_concurrency=1 \
+    --innodb_log_buffer_size=1M
 
 load_dbase_schema sakila
 load_dbase_data sakila
 mkdir $topdir/backup
 
 run_cmd_expect_failure $XB_BIN $XB_ARGS --datadir=$mysql_datadir --backup \
-    --innodb_log_file_size=1M --target-dir=$topdir/backup --suspend-at-end &
-
-xb_pid=$!
+    --innodb_log_file_size=1M --target-dir=$topdir/backup \
+    --debug-sync="xtrabackup_copy_logfile_pause" &
+
+job_pid=$!
+
+pid_file=$topdir/backup/xtrabackup_debug_sync
 
 # Wait for xtrabackup to suspend
 i=0
-while [ ! -r $topdir/backup/xtrabackup_suspended ]
+while [ ! -r "$pid_file" ]
 do
     sleep 1
     i=$((i+1))
-    echo "Waited $i seconds for xtrabackup_suspended to be created"
+    echo "Waited $i seconds for $pid_file to be created"
 done
 
-# Stop the xtrabackup process
-kill -SIGSTOP $xb_pid
- 
-# Create 2M+ of log data
+xb_pid=`cat $pid_file`
+
+# Create 4M+ of log data
 
 $MYSQL $MYSQL_ARGS -Ns -e "CREATE TABLE tmp1 ENGINE=InnoDB SELECT * FROM payment" sakila
 $MYSQL $MYSQL_ARGS -Ns -e "CREATE TABLE tmp2 ENGINE=InnoDB SELECT * FROM payment" sakila
 $MYSQL $MYSQL_ARGS -Ns -e "CREATE TABLE tmp3 ENGINE=InnoDB SELECT * FROM payment" sakila
 
 # Resume the xtrabackup process
+vlog "Resuming xtrabackup"
 kill -SIGCONT $xb_pid
 
-rm -f $topdir/backup/xtrabackup_suspended
-
 # wait's return code will be the code returned by the background process
-wait $xb_pid
+run_cmd wait $job_pid