Suboptimal MySQL ORDER BY implementation, especially together with LIMIT is often the cause of MySQL performance problems. Here is what you need to know about MySQL ORDER BY LIMIT optimization to avoid these problems.
MySQL ORDER BY with LIMIT is the most common use of ORDER BY in interactive applications with large data sets being sorted. […]
Today MySQL published the press release with results of Database Contest (results on German available here http://www.mysql.de/ct-dbcontest).
Peter and me spent quite some time working on this project while being employed by MySQL and it is great to see results finally publicly available.
The story began about year ago when C’T magazine had called for Database […]
Whenever I see benchmark results I try to understand if it is technical benchmark – made by people seeking the truth or it is done by Marketing department to wash your brains. Watch out. Whenever you treat marketing benchmarks as technical ones, you make make wrong decision. Take […]Read more
If someone asks me about MySQL Backup advice my first question would be if they have LVM installed or have some systems with similar features set for other operation systems. Veritas File System can do it for Solaris. Most SAN systems would work as well.
What is really needed is ability […]
As I already announced last week I started MySQL Performance Forums project focusing on MySQL Performance discussions as it names says.
I spend planty of time replying questions and thought it would be good idea to provide weekly overviews of most interesting topic discussed. Here is the list for last week:
Ways to perform […]Read more
Sysbench is benchmark developed by Alexey Kopytov (software engineer @ MySQL AB)
– http://sysbench.sourceforge.net/ and I want to write a short intro about this tool as sysbench is one of software for my everyday use. For example, SUN published their Solaris vs RedHat stuff based on sysbench’s results (Peter and me provided performance consutling for […]
About every second application I look at has some tables which have redundant or duplicate indexes so its the time to speak about these a bit.
So what is duplicate index ? This is when table has multiple indexes defined on the same columns. Sometimes it is indexes with different names, sometimes […]
Few days ago I wrote an article about using UNION to implement loose index scan.
First I should mention double IN also works same way so you do not have to use the union. So changing query to:
mysql> SELECT sql_no_cache name FROM people WHERE age in(18,19,20) AND zip IN (12345,12346, 12347);