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Ten MySQL performance tuning settings after installation.MySQL 5.7 performance tuning immediately after installation.MySQL server memory usage troubleshooting tips.In practice, I suspect there will be some performance related hiccups of using this feature, but it is at least a big step in the right direction. Seeing some swap activity? Just turn it down with no restart required.
#SWAM ENGINE BUFFER SIZE TOO SMALL FREE#
Seeing lots of free RAM (and/or filesystem cache usage)? Turn the buffer pool up dynamically. This sounds good in principle, but again, it requires a bunch of restarts and may be easier said than done.įortunately MySQL 5.7 and it’s online buffer pool resize feature should make this an easier principle to follow. So what’s a better rule of thumb? My rule is that you tune the innodb_buffer_pool_size as large as possible without using swap when the system is running the production workload. I think for most people it starts and ends at the rule of thumb, mostly because changing the InnoDB buffer pool requires a restart in current releases. However, as we can see above, the larger the server, the more likely the rule will wind up wasting RAM. You do want to be sure the server has plenty of free RAM for the OS and the usually unknown workload. How should you tune innodb_buffer_pool_size?Ĩ0% is maybe a great start and rule of thumb. He then, if memory serves, clarified it and said it would not apply similarly to larger servers. He said something to the effect of (not a direct quote): “Well, the server I was testing on had 1GB of RAM and 80% seemed about right”. I distinctly remember asking about the 80% rule because at the time Yahoo had some beefy 64G servers and the rule wasn’t sitting right with me. So, if you really just spent all that money on a beefy server do you really want to pay a 20% tax on that resource because of this rule of thumb? The origins of the ruleĪt one of my first MySQL conferences, probably around 2006-2007 when I worked at Yahoo, I attended an InnoDB tuning talk hosted by Heikki Tuuri (the original author of InnoDB) and Peter Zaitsev. Our server that has 1TB of RAM likely doesn’t need 205G of that to handle things like connections and queries (likely MySQL couldn’t handle that many active connections and queries anyway).
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For the rule to hold true, it must mean that workload memory consumption increases in proportion to the needed size of the buffer pool, but that usually isn’t the case. However, as we get into large servers, it starts to seem less sane. Assuming we don’t know anything really about the workload on the system yet, but we know that the system is dedicated to InnoDB, how might our 80% rule play out? Total Server RAMĪt lower numbers, our 80% rule looks pretty reasonable. A rule of thumb to help us get a quick tuning number to get the server running. However, for the sake of argument, let’s say the 80% rule is a starting point. We can see clearly that the 80% rule isn’t as nuanced as reality. Does the server have a lot of open connections and active query workload consuming memory? The memory consumption caused by this can be dramatically different server to server.įinally, replication mechanisms like Galera have their own memory usage pattern and can require some adjustments to your buffer pool. If it (and other memory consumption on the server) is too large, swapping can kick in and degrade your performance rapidly.įurther, the workload of the MySQL server itself may cause a lot of variation. It’s expected to occupy most of the RAM on a dedicated MySQL/Innodb server, but of course, other local services may affect how it is tuned.
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There’s no question that for tuning InnoDB, the innodb_buffer_pool_size is the most important variable. Any other services on the same server: Web server, caching server, cronjobs, etc.MySQL replication usage: binary log cache, replication connections, Galera gcache and cert index, etc.MySQL workload based usage: connections, per-query buffers (join buffer, sort buffer, etc.).MySQL fixed usage: query cache, InnoDB buffer pool size, mysqld rss, etc.OS Usage: Kernel, running processes, filesystem cache, etc.This list isn’t necessarily complete, but I think it outlines the large areas a MySQL server could consume memory.
#SWAM ENGINE BUFFER SIZE TOO SMALL MANUAL#
The MySQL manual to this day refers to this rule, so who can blame the DBA? The question is: does it makes sense? What uses the memory on your server?īefore we question such advice, let’s consider what can take up RAM in a typical MySQL server in their broad categories. This is such prolific tuning advice, it seems ingrained in many a DBA’s minds. It seems these days if anyone knows anything about tuning InnoDB, it’s that you MUST tune your innodb_buffer_pool_size to 80% of your physical memory.