xbstream stream mode issues a warning on standard output messing up the backup stream

[Endre Hirling]

Using

innobackupex --slave-info --stream=xbstream --compress --compact > backup.xbstream

from percona-xtrabackup 2.1.6-702-1.precise

backup.xbstream will contain a warning message at the beginning so xbstream cannot restore the files until it's removed.

[Endre Hirling (endre-hirling)]

The beginning of the stream looks like:

# A software update is available:
# * Security vulnerability. See http://www.mysqlperformanceblog.com/2012/09/10/introducing-the-version-check-feature-in-percona-toolkit/

XBSTCK01^@P^O^@^@^@./backup-my.cnf^M^A^@^@^@^@^@^@^@^@^@^@^@^@^@^@<C3>^SV<# This MySQL options file was generated by innobackupex-1.5.1.

[Raghavendra D Prabhu (raghavendra-prabhu)]

@Endre,

Not able to replicate with default binary, I see XBSTCK01 as the
first word in header, though it may be due to version-check
(which you can circumvent with --no-version-check). Also, you are
missing temporary directory (usually /tmp) on that cmdline.

[Endre Hirling (endre-hirling)]

Unfortunately I'm not able to reproduce this any more either, despite not changing anything in the environment, so I think it's safe to close this issue as unreproducable. Thanks for investigating.

[Alexey Kopytov (akopytov)]

Garbage in the xbstream output was indeed produced by the VersionCheck feature. Whether it will produce any output on STDOUT depends on many factors:

- presence of the state file in one of the following locations: /etc/percona/percona-version-check, /etc/percona-toolkit/percona-version-check, /tmp/percona-version-check, $HOME/percona-version-check
- time when the last version check was performed per the state file
- server version being backed up
- whether the VersionCheck database at v.percona.com contains any records corresponding to the server version

The workaround is to disable VersionCheck with the --no-version-check option.

[Willem Fibbe (willem-x)]

More debug-output regarding 'magic chunk' errors might help getting insight into what causes the stream to be corrupted (in the future).

After compiling xbstream with the attached patch, from the output I could see we were experiencing this bug, for instance.

This might help debug other issues.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXB-394