Emergency

Monthly Archives: November 2008

Computing 95 percentile in MySQL

When doing performance analyzes you often would want to see 95 percentile, 99 percentile and similar values. The “average” is the evil of performance optimization and often as helpful as “average patient temperature in the …

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MySQL for Hosting Providers – how do they manage ?

Working with number of hosting providers I always wonder how do they manage to keep things up given MySQL gives you so little ways to really restrict how much resources single user can consume. I …

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A quick way to get memcached status

There are all sorts of different interfaces to memcached, but you don’t need any of them to make requests from the command line, because its protocol is so simple. Try this, assuming it’s running on …

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Thanks Giving Challenge: How to detect replication context

Happy Thanksgiving and little holiday challenge for you. Say you have a trigger on the slave which you would like to work differently, depending on whenever update is executed via replication thread vs updating table …

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Using Multiple Key Caches for MyISAM Scalability

I have written before – MyISAM Does Not Scale, or it does quite well – two main things stopping you is table locks and global mutex on the KeyCache. Table Locks are not the issue …

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How Percona does a MySQL Performance Audit

Our customers or prospective customers often ask us how we do a performance audit (it’s our most popular service). I thought I should write a blog post that will both answer their question, so I …

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Using INFORMATION_SCHEMA instead of shell scripting

INFORMATION_SCHEMA, in particular by favorite TABLES table is not only helpful to understand tables you have on the system, but I have also found it to be very helpful as a scripting language for variety …

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How to calculate a good InnoDB log file size

Peter wrote a post a while ago about choosing a good InnoDB log file size.  Not to pick on Peter, but the post actually kind of talks about a lot of things and then doesn’t …

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The patches are going to Launchpad

After some discussions on the OpenSQLCamp 2008 conference we decided to move our development to Launchpad, to be in stream with other MySQL related projects. We published our patches there https://code.launchpad.net/percona-patches, it is supposed to …

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Percona build7 with latest patches

We made new binaries for MySQL 5.0.67 build 7 which include patches we recently announced. The -percona release includes:

and -percona-highperf release additionaly includes

You can download RPMs for RedHat / CentOS 4.x …

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