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Search Results for: mysql using session variable in select

Review of MySQL 5.6 Defaults Changes

James Day just posted the great summary of defaults changes in MySQL 5.6 compared to MySQL 5.5 In general there are a lot of good changes and many defaults are now computed instead of hardcoded. …

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Join Optimizations in MySQL 5.6 and MariaDB 5.5

This is the third blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is targeted at the join …

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Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5

This is the second blog post in the series of blog posts leading up to the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. This blog post is aimed at the optimizer …

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Troubleshooting MySQL Memory Usage

One of the most painful troubleshooting tasks with MySQL is troubleshooting memory usage. The problem usually starts like this – you have configured MySQL to use reasonable global buffers, such as innodb_buffer_size, key_buffer_size etc, you …

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How Percona diagnoses MySQL server stalls

We receive many requests for help with server stalls. They come under various names: lockup, freeze, sudden slowdown. When something happens only once or twice a day, it can be difficult to catch it in …

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Ultimate MySQL variable and status reference list

I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the …

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MySQL Users Conference Presentation Proposals

OK, I am not getting too much people feedback on what would they like to hear about on MySQL Users Conference, so I went ahead and submitted few presentation ideas. I do not expect all …

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MySQL: Followup on UNION for query optimization, Query profiling

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 …

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TokuDB Table Optimization Improvements

Section I: Fractal Tree and Optimization Overview Tokutek’s Fractal Tree® technology provides fast performance by injecting small messages into buffers inside the Fractal Tree index. This allows writes to be batched, thus eliminating I/O that is …

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