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Displaying posts with tag: jemalloc (reset)
MySQL Memory Management, Memory Allocators and Operating System

When users experience memory usage issues with any software, including MySQL®, their first response is to think that it’s a symptom of a memory leak. As this story will show, this is not always the case.

This story is about a bug.

All Percona Support customers are eligible for bug fixes, but their options vary. For example, Advanced+ customers are offered a HotFix build prior to the public release of software with the patch. Premium customers do not even have to use Percona software: we may port our patches to upstream for them. But for Percona products all Support levels have the right to have a fix.

Even so, this does not mean we will fix every unexpected behavior, even if we accept that behavior to be a valid bug. One of the reasons …

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Fun with Bugs #82 - On MySQL Bug Reports I am Subscribed to, Part XVIII

I've got few comments to my post on references to MariaDB in MySQL bug reports (not in the blog, but via social media and in personal messages), and all but one comments from current and former colleagues whose opinion I value a lot confirmed that this really looks like a kind of attempt to advertise MariaDB. So, from now on I'll try to keep my findings on how tests shared by MySQL bug reporters work in MariaDB for myself, MariaDB JIRA and this blog (where I can and will advertise whatever makes sense to me), and avoid adding them to MySQL bug reports.

That said, I still think that it's normal to share links to MariaDB bug reports that add something useful (like patches, …

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More on MyRocks Performance for Bug #68079 Case

My previous post on MyRocks was intended to provide some background details for a couple of slides for my FOSDEM talk on profiling MySQL. The results and performance demonstrated by MyRocks vs InnoDB from MySQL 5.7.17 were not really important to show how perf helps to understand where the time was spent while executing of one specific query vs the other (with the same results, but different plan), but they still caused a lot of comments from people who care, so I decided to double check and clarify few more details.

First of all, it was …

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Enabling and Disabling Jemalloc on Percona Server

This post discusses enabling and disabling jemalloc on Percona Server for MySQL.

The benefits of jemalloc versus glibc for use with MySQL have been widely discussed. With jemalloc (along with Transparent Huge Pages disabled) you have less memory fragmentation, and thus more efficient resource management of the available server memory.

For standard installations of Percona Server 5.6+ (releases starting with 5.6.19-67.0), the only thing needed to …

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MariaDB 5.5.33 Now Available

The MariaDB project is pleased to announce the immediate availability of MariaDB 5.5.33. This is a Stable (GA) release. See the Release Notes and Changelog for detailed information on this release and the What is MariaDB 5.5? page in the AskMonty Knowledgebase for general information about the MariaDB 5.5 series.

Download MariaDB 5.5.33

Release Notes Changelog

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Memory allocators: MySQL performance improvements in Percona Server 5.5.30-30.2

In addition to the problem with trx_list scan we discussed in Friday’s post, there is another issue in InnoDB transaction processing that notably affects MySQL performance – for every transaction InnoDB creates a read view and allocates memory for this structure from heap. The problem is that the heap for that allocation is destroyed on each commit and thus the read view memory is reallocated on the next transaction.

There are two aspects of this problem:

1) memory allocation is an costly operation and if memory …

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Showing entries 1 to 6