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POAuto-deleting mySQL query cache?
 

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  1. POAuto-deleting mySQL query cache?
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    <p>I'm the owner of a web-game with a high-traffic database with a lot of queries. I'm now optimizing the mySQL and tools like mysqltuner keep saying that I have insufficient query cache memory.</p> <pre><code>+-------------------------+-----------+ | Variable_name | Value | +-------------------------+-----------+ | Qcache_free_blocks | 218 | | Qcache_free_memory | 109155712 | | Qcache_hits | 60955602 | | Qcache_inserts | 38923475 | | Qcache_lowmem_prunes | 100051 | | Qcache_not_cached | 10858099 | | Qcache_queries_in_cache | 19384 | | Qcache_total_blocks | 39134 | +-------------------------+-----------+ </code></pre> <p>That's from about 1,5 day of running the server. Ideally the lowmem_prunes would be 0 of course, but there are very much queries which are user-based. Like, </p> <pre><code>SELECT username FROM users WHERE id='1'; SELECT username FROM users WHERE id='12'; SELECT username FROM users WHERE id='12453'; SELECT username FROM users WHERE id='122348'; </code></pre> <p>As I have about 3000 different users a day logging in you will have many queries like this in the memory.</p> <p>I know about the ON DEMAND rule, but I'm avoiding it because we have a lot of queries which I don't want to check all over.</p> <p>Increasing the memory wouldn't be a fix either since we're having so many queries.</p> <p>Then I came up with the idea to make a cronjob to automatically RESET the query cache when the lowmem_prunes is zero. (which will probably be once an hour)</p> <p><strong>What's the best option?</strong><br> 1. Automatically reset the query cache once an hour<br> 2. Buy more RAM and increase the cache with 1GB for example (which has it's downsides... I rather not do that)<br> 3. Specify per query which should be kept in cache in which not.<br> 4. Just keep it like this.</p>
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