Percona XtraBackup moved to https://jira.percona.com/projects/PXB

xb_incremental.sh checksum mismatch errors with open transactions across backups

Bug #1119451 reported by Laurynas Biveinis on 2013-02-08

This bug affects 1 person

Affects		Status	Importance	Assigned to	Milestone
	Percona XtraBackup moved to https://jira.percona.com/projects/PXB	Invalid	Undecided	Unassigned

Bug Description

Discovered while working on bug 1119186.

The current xb_incremental.sh is:

1. CREATE TABLE test;
2. load test;
3. perform a full backup;
4. CREATE TABLE t2;
5. load t2 and add to test;
6. save test and t2 checksums;
7. perform an incremental backup;
7. prepare and restore back;
8. compare checksums.

If this is augmented by a new long transaction that
a. starts after step 2;
b. inserts a row anywhere between steps 2 and 6;
c. commits before step 6,

then the test fails with a checksum mismatch for table test.

This also happens if XA transactions are used.

Revision history for this message

Laurynas Biveinis (laurynas-biveinis) wrote on 2013-03-18:

Testcase Edit (6.4 KiB, text/x-sh)

A patched testcase to show the bug (needs common.inc changes to be uploaded too)

Revision history for this message

Laurynas Biveinis (laurynas-biveinis) wrote on 2013-03-18:

inc/common.sh changes to support the testcase:

$ bzr diff test/inc/common.sh
=== modified file 'test/inc/common.sh'
--- test/inc/common.sh 2013-03-08 04:37:16 +0000
+++ test/inc/common.sh 2013-03-18 05:20:44 +0000
@@ -436,5 +436,20 @@
return ${PIPESTATUS[0]}
}

+function open_persistent_mysql_pipe()
+{
+ local pipe=$(mktemp -u)
+ mkfifo -m 600 $pipe
+ eval "$1=$pipe"
+ (tail -f $pipe) | ${MYSQL} ${MYSQL_ARGS} &
+}
+
+function close_persistent_mysql_pipe()
+{
+ local pipe=$1
+ echo "exit" > $pipe
+ rm $pipe
+}
+
# To avoid unbound variable error when no server have been started
SRV_MYSQLD_IDS=

Revision history for this message

Alexey Kopytov (akopytov) wrote on 2014-01-03:

I cannot reproduce the failure with the attached test case. Tried with xtrabackup_55 and xtrabackup_56.

no longer affects:	percona-xtrabackup/2.0
no longer affects:	percona-xtrabackup/2.1
no longer affects:	percona-xtrabackup/2.2
Changed in percona-xtrabackup:
status:	Triaged → Incomplete
importance:	Low → Undecided
milestone:	2.2.0 → none