Comment 17 for bug 1192834

For the record the duplicate bug:
https://bugs.launchpad.net/percona-xtrabackup/+bug/1444156

Contains a patch disabling purge thread:

1. xtrabackup creating ibd file with secondary index pages filled with "empty" pages. Each empty page started from deadbeef
2. xtrabackup starting innodb engine including purge thread
3a. xtrabackup filling secondary index pages with correct copies
3b. at the same time with 3a, purge thread could try to modify a secondary index page

A correct solution for the problem should include freezing of purge and change buffer activity untill expand will finish it's work.

The patch disabling purge will not work correctly with export option, because undo segment changes should be applied before exporting tablespace.