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Displaying posts with tag: Performance (reset)
May
17
2010
InnoDB recovery gets even faster in Plugin 1.1, thanks to native AIO
Posted by InnoDB Team on Mon 17 May 2010 16:28 UTC
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InnoDB Plugin 1.1 doesn’t add any recovery specific improvements on top of what we already have in Plugin 1.0.7. The details on the latter are available in this blog. Yet, when I tried to recover another big recovery dataset I created, I got the following results for total recovery time:

  • Plugin 1.0.7: 46min 21s
  • Plugin 1.1: 32min 41s

Plugin 1.1 recovery is 1.5 times faster. Why would that happen? The numerous concurrency improvements in Plugin 1.1 and MySQL 5.5 can’t really affect the recovery. The honor goes to Native Asynchronous IO on Linux. Let’s try without it:

  • Plugin 1.1 with –innodb-use-native-aio=0: 49min 07s

which is about the same as 1.0.7 time. My numerous other recovery runs showed that the random fluctuations account for 2-3min of a …

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May
14
2010
MySQL 5.1.46 With InnoDB Plugin Kicks Butt
Posted by Gerardo Narvaja on Fri 14 May 2010 19:00 UTC
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We were discussing the recommendations we issue each quarter around MySQL and the question of using InnoDB plugin came up. We usually follow Planet MySQL closely, so we read what the blogs had to say and it was all good, but we decided to provide our users some data of our own. We used our own sysbench tests on to get the information we needed.
A Word About BenchmarksI don't trust most of the benchmarks that are published online because they really apply to the use case of whomever is writing the article. They are usually many factors that can influence them and I find it difficult to apply them as-is to our environment.

I do trust the benchmarks published online as a reference on how to create and run our own benchmarks. So this article is based on this premise. I recommend you to do your own homework to …

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May
13
2010
Limited SELECT count(*)
Posted by Ilan Hazan on Thu 13 May 2010 21:52 UTC
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A SELECT statement with COUNT returns the number of rows retrieved by the SELECT statement (see mysql select count). For performance reasons, the desired result is to limit that count. Including a LIMIT clause in the SELECT statement will not work since it only restricts the number of rows returned, which is always one. The […]

May
12
2010
BlitzDB Concurrent Testing and Write Performance
Posted by Toru Maesaka on Wed 12 May 2010 06:42 UTC
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Last month while being at the MySQL Conference, several people asked me about the status of BlitzDB. Specifically, they were interested in when I’ll release BlitzDB. Fair enough – I’ve been working on this project long enough for people to start questioning this.

The answer is, BlitzDB is done in terms of implementing the design. Right now it’s about finding bugs, fixing it and testing BlitzDB’s stability under concurrent load. Thanks to the motivation boost I gained at the conference, I’ve now fixed the bugs that were slowing me down and I’m gradually adding more tests into BlitzDB’s test suite. I consider BlitzDB’s initial release to be the day it gets merged into Drizzle’s trunk. This is almost ready as BlitzDB seems to be building fine on Drizzle’s Build Farm infrastructure. However, I won’t move to the next step until I’m satisfied with BlitzDB’s stability.

Yesterday I spent some time doing some …

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May
11
2010
Why is my database slow?
Posted by Ronald Bradford on Tue 11 May 2010 21:31 UTC
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Not part of my Don’t Assume series, but when a client states “Why is my database slow”", you need to determine if indeed the database is slow.

Some simple tools come to the rescue here, one is Firebug. If a web page takes 5 seconds to load, but the .htm file takes 400ms, and the 100+ assets being downloaded from one base url, then is the database actually slow? Tuning the database will only improve the 400ms portion of 5,000ms download.

There some very simple tips here. MySQL is my domain expertise and I will not profess to improving the entire stack however perception is everything to a user and you can often do a lot. Some simple points include:

  • Know about blocking assets in your <head> element, e.g. .js files.
  • Streamline .js, .css and images to what’s needed. .e.g. download a 100k image only to resize to a thumbnail via style …
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May
11
2010
MySQL Query Engine Scalability Issues
Posted by Venu Anuganti on Tue 11 May 2010 08:27 UTC
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Lately in the MySQL community, we only hear about scalability or performance improvements of storage engines, but nothing about query engine itself. For example, one classic example being InnoDB; if[...]

May
10
2010
sort_buffer_size and Knowing Why
Posted by Sheeri K. Cabral on Mon 10 May 2010 16:53 UTC
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In How to tune MySQL’s sort_buffer_size, Baron gives a condescending viewpoint on how to tune the sort_buffer_size variable in MySQL. In a much-nicer-nutshell, his advice is “do not change sort_buffer_size from the default.”

Baron did not explain the logic behind his reasoning, he handwaves that “people utterly ruin their server performance and stability with it,” but does not explain how changing the sort_buffer_size kills performance and stability. Regardless of how respected and knowledgeable the source, NEVER take any advice that tells you what to do or how to do it without understanding WHY.

This article will explain the “why” of Baron’s point, and it will also talk more about understanding why, an integral part against the “Battle against any guess.” Baron’s recommendation to leave …

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May
06
2010
Two quick performance tips with MySQL 5.1 partitions
Posted by Giuseppe Maxia on Thu 06 May 2010 09:20 UTC
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While I was researching for my partitions tutorial, I came across two hidden problems, which may happen often, but are somehow difficult to detect and even more difficult to fix, unless you know what's going on, and why. I presented both cases during my tutorial, but there were no pictures to convey the mechanics of the problem. Here is the full story.

TO_DAYS() prunes two partitions instead of one
If you are partitioning by date, chances are that you are using TO_DAYS(). And depending on how you have partitioned your table, your queries are as fast as you expect them to be. However, there are cases where your query takes twice as long as it should, and of course this will not make you happy.

For example, in a table partitioned by month, when …

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May
01
2010
A review of Forecasting Oracle Performance by Craig Shallahamer
Posted by Baron Schwartz (xaprb) on Sat 01 May 2010 18:47 UTC
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Forecasting Oracle Performance

Forecasting Oracle Performance. By Craig Shallahamer, Apress 2007. Page count: about 250 pages. (Here’s a link to the publisher’s site). Short version: buy it and read it, but make sure you don’t rely on it alone; deepen your knowledge through other sources.

I bought and read this book because I’m interested in performance, performance forecasting, and capacity planning. I’m not interested in forecasting Oracle performance per se. However, I have noticed that there is a lot of good literature in the Oracle arena that can apply to other databases (*cough* …

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Apr
27
2010
MySQL Cluster - SPJ Preview - Feedback welcome
Posted by Johan Andersson on Tue 27 Apr 2010 10:55 UTC
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SPJ (preview, not production ready) is a new feature allowing some types of JOINs to be pushed down and executed inside the data nodes! This allows for, in many cases, much faster JOIN execution.

Now we would love to get your feedback on this new feature:

  • Does what we have right now improve performance for you?
  • Are there other types of JOINs we should support in order to improve performance in you application (currently only eq_ref is supported)?
  • What application are you using?

There are some limitations currently:

  • node failure handling of SPJ is not complete, so if a data node crash, there are side-effects.
  • only eq_ref is supported - other JOINs are executed as normal.
  • Don't put this in production.

Obtaining the MySQL Cluster SPJ preview version:

  • You must know how to build MySQL Cluster …
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