Emergency

Monthly Archives: September 2009

Admin notice: comments again broken

(This note should not go to PlanetMySQL, sorry if it goes). We again have problem with comments to blog posts. It’s technical problem, we did upgrade some components and it seems it affected captcha. We …

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Quick comparison of MyISAM, Infobright, and MonetDB

Recently I was doing a little work for a client who has MyISAM tables with many columns (the same one Peter wrote about recently). The client’s performance is suffering in part because of the number …

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How number of columns affects performance ?

It is pretty understood the tables which have long rows tend to be slower than tables with short rows. I was interested to check if the row length is the only thing what matters or …

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Why InnoDB index cardinality varies strangely

This is a very old draft, from early 2007 in fact. At that time I started to look into something interesting with the index cardinality statistics reported by InnoDB tables. The cardinality varies because it’s …

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InnoDB/XtraDB Training in New York City!

Our Santa Clara/San Francisco training went great – 100% of survey respondents said they would recommend the same course to a friend.  I’m pleased to announce that such an opportunity exists – our next training …

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Speaking at Highload.ru

This is a quick announcement to say that I’ll be speaking at HighLoad++ this year (October 12-14 in Moscow).  I’ll be presenting on a few topics: MySQL Performance Tuning (Conference Session) Quick Wins with Third …

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Guidance for MySQL Optimizer Developers

I spend large portion of my life working on MySQL Performance Optimization and so MySQL Optimizer is quite important to me. For probably last 10 years I chased first Monty and later Igor with Optimizer …

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Multi Column indexes vs Index Merge

The mistake I commonly see among MySQL users is how indexes are created. Quite commonly people just index individual columns as they are referenced in where clause thinking this is the optimal indexing strategy. For …

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Attempting to Quantify Fragmentation Effects

We often hear from customers and MySQL experts that fragmentation causes problems such as wasting disk space, increasing backup times, and degrading performance. Typical remedies include periodic “optimize table” or dump and re-load (for example, …

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How to generate per-database traffic statistics using mk-query-digest

We often encounter customers who have partitioned their applications among a number of databases within the same instance of MySQL (think application service providers who have a separate database per customer organization … or wordpress-mu …

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