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Redundant index is not always bad

 | August 28, 2007 |  Posted In: Benchmarks, Insight for DBAs

About year ago Peter wrote about redundant indexes and mentioned sometimes it is good to leave two indexes, even one is first part of another. I’m speaking about BTREE indexes, for example, KEY (A), and KEY (A,B). From SQL point of view KEY(A) is not needed, as for queries like WHERE A=5 the index (A,B) […]

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Memory allocation in Stored Function

 | August 26, 2007 |  Posted In: Insight for DBAs

UPDATE : Post is not actual anymore Not so long time ago I had task to update string column in table with 10mil+ rows, and, as the manipulation was non-trivial, I decided this task is good to try Stored Function. Function written – go ahead. Since 5 min I got totally frozen box with no […]

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Should MySQL Extend GROUP BY Syntax ?

 | August 17, 2007 |  Posted In: Insight for Developers

Jan has a good article about finding the row matching some value in the group: This is one illustration of group by limitations in SQL language which is not offset by any MySQL specific extensions,yet As you can see if you want to get one row from the group which is sorted some way you […]

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Yahoo Search Suggestions for MySQL

 | August 16, 2007 |  Posted In: Events and Announcements

I noticed today if you go to Yahoo.com and type MySQL to Search field it gives you suggestions for MySQL, which are: * loading javascript arrays with mysql data * mysql performance blog * mysql download * mysql administrator download * mysql front download It may not be best search suggestions but it is cool […]

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MySQL Community Needs

 | August 15, 2007 |  Posted In: Events and Announcements

Sheeri just posted a great post putting a different view on recent MySQL Community Announcements. This however raises very interesting point what MySQL Community really needs ? I think the problem is there are no single set of needs for Community which can be maintained within single version. I see at least two set of […]

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MySQL VIEW as performance troublemaker

 | August 12, 2007 |  Posted In: Insight for DBAs

I start to see applications being built utilizing VIEWs functionality which appeared in MySQL 5.0 and quite frequently VIEWs are used to help in writing the queries – to keep queries simple without really thinking how it affects server performance. Even worse than that – looking at the short table which just gets single row […]

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