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| author | Sunny Bains <Sunny.Bains@Oracle.Com> | 2011-02-22 16:04:08 +1100 |
|---|---|---|
| committer | Sunny Bains <Sunny.Bains@Oracle.Com> | 2011-02-22 16:04:08 +1100 |
| commit | b3c9cc6f212c650a18ca191a8889e2af68ffc9d6 (patch) | |
| tree | e08735bb00ffdf755168e1ab09f21f26b6f19441 /storage/innobase/ut/ut0ut.c | |
| parent | be59ca8275a3e0c95001af3077e1b4f6dc736739 (diff) | |
| download | mariadb-git-b3c9cc6f212c650a18ca191a8889e2af68ffc9d6.tar.gz | |
Bug #11766227: InnoDB purge lag much worse for 5.5.8 versus 5.1
Bug #11766501: Multiple RBS break the get rseg with mininum trx_t::no code during purge
Bug# 59291 changes:
Main problem is that truncating the UNDO log at the completion of every
trx_purge() call is expensive as the number of rollback segments is increased.
We truncate after a configurable amount of pages. The innodb_purge_batch_size
parameter is used to control when InnoDB does the actual truncate. The truncate
is done once after 128 (or TRX_SYS_N_RSEGS iterations). In other words we
truncate after purge 128 * innodb_purge_batch_size. The smaller the batch
size the quicker we truncate.
Introduce a new parameter that allows how many rollback segments to use for
storing REDO information. This is really step 1 in allowing complete control
to the user over rollback space management.
New parameters:
i) innodb_rollback_segments = number of rollback_segments to use
(default is now 128) dynamic parameter, can be changed anytime.
Currently there is little benefit in changing it from the default.
Optimisations in the patch.
i. Change the O(n) behaviour of trx_rseg_get_on_id() to O(log n)
Backported from 5.6. Refactor some of the binary heap code.
Create a new include/ut0bh.ic file.
ii. Avoid truncating the rollback segments after every purge.
Related changes that were moved to a separate patch:
i. Purge should not do any flushing, only wait for space to be free so that
it only does purging of records unless it is held up by a long running
transaction that is preventing it from progressing.
ii. Give the purge thread preference over transactions when acquiring the
rseg->mutex during commit. This to avoid purge blocking unnecessarily
when getting the next rollback segment to purge.
Bug #11766501 changes:
Add the rseg to the min binary heap under the cover of the kernel mutex and
the binary heap mutex. This ensures the ordering of the min binary heap.
The two changes have to be committed together because they share the same
that fixes both issues.
rb://567 Approved by: Inaam Rana.
Diffstat (limited to 'storage/innobase/ut/ut0ut.c')
| -rw-r--r-- | storage/innobase/ut/ut0ut.c | 9 |
1 files changed, 1 insertions, 8 deletions
diff --git a/storage/innobase/ut/ut0ut.c b/storage/innobase/ut/ut0ut.c index 4f4dfc5eed8..cd0894b132a 100644 --- a/storage/innobase/ut/ut0ut.c +++ b/storage/innobase/ut/ut0ut.c @@ -1,13 +1,6 @@ /***************************************************************************** -Copyright (c) 1994, 2010, Innobase Oy. All Rights Reserved. -Copyright (c) 2009, Sun Microsystems, Inc. - -Portions of this file contain modifications contributed and copyrighted by -Sun Microsystems, Inc. Those modifications are gratefully acknowledged and -are described briefly in the InnoDB documentation. The contributions by -Sun Microsystems are incorporated with their permission, and subject to the -conditions contained in the file COPYING.Sun_Microsystems. +Copyright (c) 2011, Oracle Corpn. All Rights Reserved. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software |