Emergency

Monthly Archives: May 2009

Using netcat to copy MySQL Database

This is mainly a cheat sheet for me to remember. Nothing rocket science. It often makes sense to use netcat/nc to copy MySQL database between hosts in trusted networks. It bypasses encryption overhead of SSH …

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Clustering indexes vs. Covering indexes

Yesterday, I (Zardosht) posted an entry introducing clustering indexes. Here, I elaborate on three differences between a clustering index and a covering index: Clustering indexes can create indexes that would otherwise bounce up against the …

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Introducing Multiple Clustering Indexes

In this posting I’ll describe TokuDB’s multiple clustering index feature. In general (not just for TokuDB) a clustered index or a clustering index is an index that stores the all of the data for the …

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Publications Related to Fractal Tree Indexing

The TokuDB storage engine for MySQL employs Fractal Tree technology. We’ve been planning to write a white paper explaining how fractal tree indexing works, but haven’t gotten to it yet. In the mean time, here …

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Open Development vs Making a Big Splash

I find it very interesting how Sun does not get the very basic principle of true community Open Source development – you’ve got to give up on making a big splash. Traditional close source company …

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Mass killing of MySQL Connections

Every so often I run into situation when I need to kill a lot of connections on MySQL server – for example hundreds of instances of some bad query is running making server unusable. Many …

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xtrabackup-0.7 (RC)

We announce next version of our xtrabackup tool and we consider it stable enough to put label RC on it. Changelist includes: – use O_DIRECT by default for handling InnoDB files – use posix fadvise …

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Hint: throttling xtrabackup

Using xtrabackup for copying files can really saturate your disks, and that why we made special option

to limit rate of IO per second. But it really works when you do local copy. What …

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MySQL Pays attention to Bugs (Finally!)

I should say I can see results of new engineering/refactoring/bug hunt efforts inside Sun/MySQL. Over last couple of weeks I started getting a lot of messages from the bugs system about bugs I reported long …

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What time 18446744073709550.000 means

Sometimes when you do profiling you can see number like this in timestamps. Periodically in our patches there was Query_time: 18446744073709550.000 in slow.log file (well, it was fixed recently, but still appears in other places). …

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