“The least expensive query is the query you never run.” Data access is expensive for your application. It often requires CPU, network and disk access, all of which can take a lot of time. Using less computing resources, particularly in the cloud, results in decreased overall operational costs, so caches provide real value by avoiding […]
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I usually tell people to use official MySQL builds from MySQL, or from their operating system distribution if they don’t want to do that. (This assumes that there is no compelling reason to use third-party builds such as Percona’s.) Sometimes, though, people want to create their own builds, or use a build that is “optimized” […]
This is the third in a series on whatâ€™s seriously limiting MySQL in certain circumstances (links: part 1, 2). This post is about subqueries, which in some cases execute outside-in instead of inside-out as users expect.
Ever wondered how fast stored routines are in MySQL? I just ran a quick micro-benchmark to compare the speed of a stored function against a “roughly equivalent” subquery. The idea — and there may be shortcomings that are poisoning the results here, your comments welcome — is to see how fast the SQL procedure code […]
One question which comes up very often is when one should use SAN with MySQL, which is especially popular among people got used to Oracle or other Enterprise database systems which are quite commonly deployed on SAN. My question in such case is always what exactly are you trying to get by using SAN ?
Occasionally there is a need to see what queries reach MySQL. The database provides several ways to share that information with you. One is called general log activated with
in MySQL 5.1+) start-up parameter. The log writes any query being executed by MySQL to a file with limited amount of additional information. […]
Recently I was working with the customer who need quick warmup – to get Innodb table fetched in memory as fast as possible to get good in memory access performance. To do it I run the query: “SELECT count(*) FROM tbl WHERE non_idx_col=0″ I use this particular form of query because it will do full […]
In my post on estimating query completion time, I wrote about how I measured the performance on a join between a few tables in a typical star schema data warehousing scenario. In short, a query that could take several days to run with one join order takes an hour with another, and the optimizer chose […]
If you’re following PlanetMySQL you’ve already seen Baron’s post about MySQL Conference which many of us just have returned from. It was great event as well as 5 conferences I’ve been before that, though however it more and more becomes MySQL marketing channel and business event rather than Users Conference as it originated. This Year […]
Yesterday I had a chance to speak to Igor – head of MySQL optimizer team and Timur – both of them expressed concern with TPC-H run results I posted and notes about little gains in MySQL 6.0. Do not get this post wrong. I’m not saying MySQL 6.0 SubQuery optimizations are non existent or priorities […]