Neuigkeiten

Thanks, got it:

hostnameX FromDual.MySQL.master.Binlog_ignore_filter 1400661892

I think I see what went wrong. Can you please send me the first 10 lines of the file /tmp/FromDualAgentCache.hostnameX.cache:

shell> head -n 10 /tmp/FromDualAgentCache.hostnameX.cache

I see… The only part in the code where exit code 1 can be reached is the signal TERM trap. Either somebody killed the process or mpm killed a long running former mpm process automatically. How do you start mpm agent?

It looks like you did not enable the master module: INFO: Modules for section hostnameX: mpm server process mysql innodb slave

Hello Obyis

Hmm... In the master module nothing has changed since v0.9.1 if I searched correctly...
It looks like the problem is located in sending the cache file.
Can you please enabled Debug = 4 and send us the output when the error happens?

Thanks,
Oli

We found a pretty uncomfortable bug. It can be fixed easily by yourself or wait for the release of version 0.9.3 coming out soon. For more information see: here.

This seems to be a bug in v0.9.2 which happens when you have deadlock error messages in SHOW ENGINE INNODB STATUS output. (bug #139).

Will be fixed in v0.9.3

Workaround: fix lines 51 and 64 in lib/InnoDbStatus.pm as follows:

-    $sha1 = Digest::SHA1->new;
+    $sha1 = Digest::SHA->new;

or as described in Abdel-Mawlas comment above.

Hello

oh, I see. The installation advice for Ubuntu/Debian has a bug. libdigest-sha1-perl does not exits (any more?). I fixed the installation docu.

But apt-get install libdigest-sha-perl should definitely work.

Oli

I’m going to deploy the new version of MPM on all my servers and i was wondering if there was a way to automatically delete or reload the cache file FromDualAgentCache.hostname.cache when we upgrade to the new version?

I’m using Puppet to deploy the new version but I can’t find a way to delete this file once, otherwise it will erase it every 30 minutes which is not good for the system.

The mpm cache file is automatically loaded from the mpm agent to the Zabbix service at every run. After the load it is automatically shrinked/deleted again. So there is no need to reload or delete this file.>/p>

In some rare case (with older releases) mpm got a hick-up with too big cache files and then it makes sense to completely delete them.

For your automatic deployment with puppet is should not affect the system at all. Can you elaborate your concerns a bit more?

OK. Try to set log_ouput to table with:

SET GLOBAL log_output = 'table';

The FromDual Ops Center for MariaDB and MySQL (focmm) is a browser-based Graphical User Interface (GUI) to operate and manage your MariaDB and MySQL database farms (2 - 99 instances) more easily.
If further provides tools to implement your own Database as a Service (DBaaS) infrastructure.

FromDual Ops Center covers the full life-cycle of a database:

• Installation of your database from different Repositories.
• Configuration of your database instance.
• Track configuration changes of your database instance. …

From throughput point of view I agree. What about from response time point of view? We fire a query once and never again (the same).

Hello Øystein,

Unfortunately I have to agree! MySQL is damn fast/cool and hardware nowadays as well. And having much RAM and fast multi-core CPU's sucks from a tuner point of view ;-)

Hi Massimo,

From my last 14 years experience as DBA and DB consultant (Oracle, MySQL, MS-SQL Server, PostgreSQL). I have seen several hundreds? different DB performance problems in these years and only few of them (1 upon 20? or even less) where real throughput problems.
Most of them where single query performance problems (including optimizer/optimizing and configuration problems).

Regards,
Oli

Hello Øystein,

The high/bad standard deviation with MySQL 5.6 comes from some very high outlier in the beginning of the test. I did not delete this outlier because I have seen this as an unfair treatment to the other releases which did not show this phenomena.

I dropped the first measurement always (memory heat-up).

And I did all the test series in the same way. So more or less same fair/unfair for all releases.

By ignoring the outlier you still can see around 5% changes in performance.

About …

Hello Stephane,

Sorry, I cannot completely follow you what you want me to do. But please feel free to reproduce. All needed information are available I think!

Oli

Hi Joffrey,

The easy answer first: 5 - 15 iterations until it got a stable response time and then I took the most optimistic value. Not very scientific, I know... But I think good enough for a reliable statement.

About InnoDB 4 byte alignment. No, it is not.

Some proves beside consulting various documentations from InnoDB table monitor:

CREATE TABLE `align` (
  `id` int(11) NOT NULL DEFAULT '0',
  `tiny` tinyint(4) DEFAULT NULL,
  `small` smallint(6) DEFAULT NULL,
  `medium` mediumint(9) DEFAULT …

There are many different possibilities how you can achieve inconsistencies between Master and Slave in a MySQL replication, intentional and non-intentional ones. How to achieve them is not the topic of this article.

What we want to know is how can we detect inconsistencies or differences between Master and Slave and how can we fix them.

To find those inconsistencies or differences we need 2 tools from the Percona Toolkit: pt-table-checksum and pt-table-sync.

Requirements

The following requirements have to …

Sehr geehrte Damen und Herren,

Am Donnerstag, 5. Dezember kommt Virident nach Zürich um ihre Enterprise Flash Speicher für den Datenbank-Einsatz vorzustellen.

Ryan Taylor und Mark Lucas werden diese fortschrittliche Technologie vorstellen und aufzeigen, wie führende Unternehmen wie LinkedIn Virident Produkte wirksam einsetzten um ihre Datenbankanwendungen zu beschleunigen. Danach zeigt Oli Sennhauser (CTO von FromDual) auf, wo und wie Flash Speicher mit MySQL (und anderen Datenbanken) am besten zum Einsatz …