Emergency

Monthly Archives: December 2007

What is the longest part of Innodb Recovery Process ?

In MySQL 4.1 and above the longest part of recovery after crash for Innodb tables could be UNDO stage – it was happening in foreground and was basically unbound – if you have large enough …

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Large result sets vs. compression protocol

mysql_connect() function in PHP’s MySQL interface (which for reference maps to mysql_real_connect() function in MySQL C API) has a $client_flags parameter since PHP 4.3.0. This parameter is barely known and almost always overlooked but in …

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MVCC: Transaction IDs, Log Sequence numbers and Snapshots

MySQL Storage Engines implementing Multi Version Concurrency Control have several internal identifiers related to MVCC. I see a lot of people being confused what they are and why they are needed so I decided to …

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Fixing column encoding mess in MySQL

Just had an interesting issue with an encoding mess on a column containing non-ASCII (Russian) text. The solution was not immediately obvious so I decided it’s worth sharing. The column (actually the whole table) was …

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Slides from Egypt talks

I published slides from my two talks from our Egypt company meeting. First one is about Sphinx search engine. The originally presentation was prepared by Andrew Aksenoff, author of Sphinx for HighLoad.ru conference, I translated …

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Back from company meeting in Hurghada, Egypt

So we’re back from the company meeting which took place last week in Hurghada, Egypt. It was a great opportunity to meet a lot of people for the first time in person to work together …

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Be careful rotating MySQL logs

If you enable logging of all queries as “slow queries” using the patch or MySQL 5.1 you can get log file to grow huge. Same may happen with general log file. In some cases we’ve …

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