Merge lp:~akopytov/percona-xtrabackup/bug1081882-2.0 into lp:percona-xtrabackup/2.0

Proposed by Alexey Kopytov
Status: Merged
Approved by: Stewart Smith
Approved revision: no longer in the source branch.
Merged at revision: 493
Proposed branch: lp:~akopytov/percona-xtrabackup/bug1081882-2.0
Merge into: lp:percona-xtrabackup/2.0
Prerequisite: lp:~akopytov/percona-xtrabackup/bug924492-2.0
Diff against target: 13 lines (+3/-0)
1 file modified
src/xtrabackup.c (+3/-0)
To merge this branch: bzr merge lp:~akopytov/percona-xtrabackup/bug1081882-2.0
Reviewer Review Type Date Requested Status
Stewart Smith (community) Approve
George Ormond Lorch III (community) g2 Approve
Review via email: mp+141918@code.launchpad.net

Description of the change

  Bug #1081882: xb_parallel_incremental test sporadically fails

  The problem was sporadic and rather rare, so one can only guess about
  the possible reasons. The most likely reason is partial page writes: if
  there is a partially written page in a block, XtraBackup retries for 10
  times to re-read before giving up.

  Naturally, it may also affects production usage, rather than just
  Jenkins builds.

  There's no ultimate fix either: regardless of how much time we allow for
  a partial page write to complete, there's always a chance it is not
  complete before we give up and claim the datafile is corrupted. However,
  spinning in a tight loop re-reading the same page(s) doesn't make much
  sense either. Given that a partial page write is supposed to be an
  extremely rare event during a backup procedure, XtraBackup can wait a
  bit longer and sleep between unsuccessful retries.

  This fix introduces a 0.1 second delay between read retries, which
  allows about 0.9 second for partial page write(s) in the same 1 MB block
  to complete.

http://jenkins.percona.com/view/XtraBackup/job/percona-xtrabackup-2.0-param/321/

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Revision history for this message
George Ormond Lorch III (gl-az) :
review: Approve (g2)
Revision history for this message
Stewart Smith (stewart) :
review: Approve

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1=== modified file 'src/xtrabackup.c'
2--- src/xtrabackup.c 2013-01-04 14:19:21 +0000
3+++ src/xtrabackup.c 2013-01-04 14:19:21 +0000
4@@ -3437,6 +3437,9 @@
5 (ulint)((offset +
6 (IB_INT64)chunk_offset)
7 >> page_size_shift));
8+
9+ os_thread_sleep(100000);
10+
11 goto read_retry;
12 }
13 }

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