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Showing entries 1 to 5

Displaying posts with tag: OOM (reset)

OOM relation to vm.swappiness=0 in new kernel
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I have recently been involved in diagnosing the reasons behind OOM invocation that would kill the MySQL server process. Of course these servers were primarily running MySQL. As such the MySQL server process was the one with the largest amount of memory allocated.

But the strange thing was that in all the cases, there was no swapping activity seen and there were enough pages in the page cache. Ironically all of these servers were CentOS 6.4 running kernel version 2.6.32-358. Another commonality was the fact that vm.swappiness was set to 0. This is a pretty much standard practice and one that is applied on nearly every server that runs …

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Improving InnoDB memory usage
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Last month we did a few improvements in InnoDB memory usage. We solved a challenging issue about how InnoDB uses memory in certain places of the code.

The symptom of the issue was that under a certain workloads the memory used by InnoDB kept growing infinitely, until OOM killer kicked in. It looked like a memory leak, but Valgrind wasn’t reporting any leaks and the issue was not reproducible on FreeBSD – it only happened on Linux (see Bug#57480). Especially the latest …

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MySQL InnoDB and table renaming don’t play well…
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At Days of Wonder we are huge fans of MySQL (and since about a year of the various Open Query, Percona, Google or other community patches), up to the point we’re using MySQL for about everything in production.

But since we moved to 5.0, back 3 years ago our production databases which hold our website and online game systems has a unique issue: the mysqld process uses more and more RAM, up …

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MySQL and the Linux swap problem
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Ever since Peter over at Percona wrote about MySQL and swap, I’ve been meaning to write this post. But after I saw Dathan Pattishall’s post on the subject, I knew I’d better actually do it.

There’s a nasty problem with Linux 2.6 even when you have a ton of RAM. No matter what you do, including setting /proc/sys/vm/swappiness = 0, your OS is going …

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Adding dynamic swap file
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All production servers are normally installed using kickstart files. Unfortunately, the ks file had a bug that it didnt add a swap partition if there was only one logical or physical disk.

Once the database was setup without swap, the configuration was sized such that all processes fit into memory. But we started seeing OOM killing processes due to lack of memory. Though under normal conditions we had 1-2 GB of free memory.

Unfortunately, OOM at times picked to kill mysql. We were running 500GB+ database having myisam tables. We ended up having to repair the tables every time OOM felt like killing mysqld . Adding a swap device …


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Showing entries 1 to 5

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