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Search Results for: access lookup column query

Missing Data – rows used to generate result set

As Baron writes it is not the number of rows returned by the query but number of rows accessed by the query will most likely be defining query performance. Of course not all row accessed …

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The MySQL optimizer, the OS cache, and sequential versus random I/O

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 …

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Heikki Tuuri Innodb answers – Part I

Its almost a month since I promised Heikki Tuuri to answer Innodb Questions. Heikki is a busy man so I got answers to only some of the questions but as people still poking me about …

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PBXT benchmarks

The PBXT Storage Engine (http://www.primebase.com/xt/) is getting stable and we decided to benchmark it in different workloads. This time I tested only READ queries, similar to ones in benchmark InnoDB vs MyISAM vs Falcon (https://www.percona.com/blog/2007/01/08/innodb-vs-myisam-vs-falcon-benchmarks-part-1) …

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InnoDB vs MyISAM vs Falcon benchmarks – part 1

Several days ago MySQL AB made new storage engine Falcon available for wide auditory. We cannot miss this event and executed several benchmarks to see how Falcon performs in comparison to InnoDB and MyISAM. The …

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ORDER BY … LIMIT Performance Optimization

Suboptimal ORDER BY implementation, especially together with LIMIT is often the cause of MySQL Performance problems. Here is what you need to know about ORDER BY … LIMIT optimization to avoid these problems ORDER BY …

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Extended EXPLAIN

One nice feature added for EXPLAIN statement in MySQL 4.1 is EXTENDED keyword which provides you with some helpful additional information on query optimization. It should be used together with SHOW WARNINGS to get information …

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Why MySQL could be slow with large tables ?

If you’ve been reading enough database related forums, mailing lists or blogs you probably heard complains about MySQL being unable to handle more than 1.000.000 (or select any other number) rows by some of the …

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