… don’t miss this conference! Secondly, remember that our support contracts cover MariaDB as a first-class member of the MySQL family of databases. Finally, High Performance MySQL, Third Edition mentions MariaDB in many places… key cache for improved scalability That’s really just a sampling. A good starting point for learning more is the MySQL versus…
Post: Cache Miss Storm
September 10, 2010 By 29 Comments
… was a cache miss storm – situation which can happen with memcache (as in this case) as well as with query cache. If you… carefully watch frequently accessed cache items as well as cache items which take long to generate in case of cache miss. To find first… cache to reflect it is being updated right now so you’re better wait rather than starting populating it. For MySQL Query Cache…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… the amazing MySQL manual, especially the option and variable …cache_hitsblogpercona.commanual Ssl_session_cache_missesblogpercona.commanual Ssl_session_cache_modeblogpercona.commanual Ssl_session_cache_overflowsblogpercona.commanual Ssl_session_cache_sizeblogpercona.commanual Ssl_session_cache…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 27 Comments
… that somewhere around of 99% of advice about tuning MySQL‘s key cache hit ratio is wrong, even when you hear it… cache miss rate is defined as the number of misses per unit of time, with the units of operations per second. The key cache miss… you trust the cache‘s creator and assume that misses are more expensive than hits, then you care about cache misses, not cache hits. A…
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 63 Comments
… MySQL Query Cache so it once again is appealing to improve performance for MySQL Applications ? Make it Lockless Can we re-implement MySQL Query Cache… from Multiple Misses So you have item invalidated from query cache and there are multiple connection requesting the same item. What MySQL will… significant hit for misses. This is especially the problem for very expensive queries. The good thing about MySQL Query Cache is it knows…
Post: table_cache negative scalability
November 16, 2009 By 23 Comments
… see 100+ misses/sec while your data (at least table headers) is well cached so the cost of table cache miss is not very high, you may be better of with significantly reduced table cache size… in MySQL 5.1, lets see how MySQL 5.4 behaves. MySQL 5.4.2 MySQL 5.4.2 has higher default table_open_cache…
Post: Beyond great cache hit ratio
May 19, 2010 By 2 Comments
… plus there are 10 more requests which resulted in misses and caused MySQL queries. The hit ratio is 90%. Imagine now you… on the cache miss. Maximize amount of uses of the cache item It is the most efficient if the item in the cache can… multiple pages and multiple users this will maximize cache efficiency while reduce amount of cache space required. The importance of this advice…
Post: Return of the Query Cache, win a Percona Live ticket
August 26, 2011 By 4 Comments
… a query-cache single choke-point in the server. Now that’s gone. As of MySQL 5.5, the query cache mutex isn’t hit at all if query_cache_type is zero. We… you get a screen full of query cache locks. It makes it impossible to miss serious contention when it happens. For example…
Post: More on dangers of the caches
September 23, 2010 By 5 Comments
… back to this case… MySQL was getting overloaded with thousands of same queries… which corresponded to cache miss storm but why it was… expiration based cache you increase the chance of conditions when system will not gradually recover by populating cache – if because of cache misses performance is so bad the speed of populating cache with new items is…
Post: Active Cache for MySQL
January 10, 2010 By 11 Comments
… cached data. This means application using Memcache has to has to special logic to handle misses from the cache, being careful updating the cache… with concept of active cache The idea with Active Cache is very simple – for any data retrieval operation cache would actually know how to construct the object, so you will never get a miss from the cache, unless there…
