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Search Results for: fixed length

Big trouble with zero-length character columns in TokuDB

What good is a zero-length character column in a MySQL table? A zero-length character column has type of ‘char(0)’. If it is nullable, then it can at least store one bit. If it is not …

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Getting MySQL to use full key length

There is one bug, or “missing feature” in MySQL Optimizer which may give you hard time causing performance problems which may be hard to track down, it is using only part of the index when …

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Q&A: Common (but deadly) MySQL Development Mistakes

On Wednesday I gave a presentation on “How to Avoid Common (but Deadly) MySQL Development Mistakes” for Percona MySQL Webinars. If you missed it, you can still register to view the recording and my slides. Thanks to …

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Innodb row size limitation

I recently worked on a customer case where at seemingly random times, inserts would fail with Innodb error 139. This is a rather simple problem, but due to it’s nature, it may only affect you …

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How InnoDB handles REDO logging

Xaprb (Baron) recently blogged about how InnoDB performs a checkpoint , I thought it might be useful to explain another important mechanism that affects both response time and throughput – The transaction log.

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Paul McCullagh answers your questions about PBXT

Following on from our earlier announcement, Paul McCullagh has responded with the answers to your questions – as well as a few I gathered from other Percona folks, and attendees of OpenSQL Camp. Thank you …

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How number of columns affects performance ?

It is pretty understood the tables which have long rows tend to be slower than tables with short rows. I was interested to check if the row length is the only thing what matters or …

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INSERT ON DUPLICATE KEY UPDATE and REPLACE INTO

Jonathan Haddad writes about REPLACE INTO and INSERT ON DUPLICATE KEY UPDATE. Really, Why MySQL has both of these, especially both are non ANSI SQL extensions ? The story here seems to be the following …

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Trailing spaces in MySQL

In the past life was easy in MySQL. Both CHAR and VARCHAR types meant the same, only being difference in the sense of fixed or dynamic row length used. Trailing spaces were removed in both …

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Percona Toolkit 2.2.15 is now available

Percona is pleased to announce the availability of Percona Toolkit 2.2.15.  Released August 28, 2015. Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or …

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