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TIMESTAMP Columns, Amazon RDS 5.6, and You

 | July 8, 2014 |  Posted In: Cloud and MySQL, Cloud and NoSQL, Insight for DBAs, Insight for Developers, MySQL

This comes from an issue that I worked on recently, wherein a customer reported that their application was working fine under stock MySQL 5.6 but producing erroneous results when they tried running it on Amazon RDS 5.6. They had a table which, on the working server, contained two TIMESTAMP columns, one which defaulted to CURRENT_TIMESTAMP […]

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Using MySQL 5.6 Performance Schema in multi-tenant environments

 | June 9, 2014 |  Posted In: Insight for DBAs, MySQL

Hosting a shared MySQL instance for your internal or external clients (“multi-tenant”) was always a challenge. Multi-tenants approach or a “schema-per-customer” approach is pretty common nowadays to host multiple clients on the same MySQL sever. One of issues of this approach, however, is the lack of visibility: it is hard to tell how many resources (queries, disk, […]

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Many-table joins in MySQL 5.6

 | March 6, 2014 |  Posted In: Insight for DBAs, MySQL

I recently worked on an uncommon slow query: less than 100 rows were read and returned, the whole dataset was fitting in memory but the query took several seconds to run. Long story short: the query was a join involving 21 tables, running on MySQL 5.1. But by default MySQL 5.1 is not good at […]

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InnoDB adaptive flushing in MySQL 5.6: checkpoint age and io capacity

 | October 30, 2013 |  Posted In: MySQL, Percona Server for MySQL

In MySQL 5.6 InnoDB has a dedicated thread (page_cleaner) that’s responsible for performing flushing operations. Page_cleaner performs flushing of the dirty pages from the buffer pool based on two factors: – access pattern  –  the least recently used pages will be flushed by LRU flusher from LRU_list when buffer pool has no free pages anymore; […]

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