Category Archives: tip

Performance_schema success stories : host summary tables

This question was asked at support by a customer to solve a difficult issue. How to identify a sporadic burst of queries coming from one of the hosts accessing the database ? If there are hundreds of hosts, it can … Continue reading

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50 tips to boost MySQL Performance Webinar follow up

Thank you for attending the webinar !  Here are the ppt slides. If you missed it, you can still join the archived event by clicking the URL below. There were a lot of attendees and a lot of questions. … Continue reading

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How to calculate a specific InnoDB index size ?

MySQL provides commands to see the overall index size versus the data size. One of them is “show table status” :

So here, we have these “estimations”, run ANALYZE TABLE before to get more accurate estimates : Data_length: 143310848, … Continue reading

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A small optimizer change worth noticing

MySQL uses internal temporary tables to execute some queries. Usually the tables are stored in memory and on disk if some conditions are met : Some conditions prevent the use of an in-memory temporary table, in which case the server … Continue reading

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Poor man’s Online Optimize in 5.6

Table space fragmentation has generally 2 origins : File System fragmentation : the data file is spread physically on many non contiguous locations on the disk. Internal Fragmentation : the data and index pages have “holes” : this happens when  … Continue reading

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