… from disk. Replaying Queries Working with Groupon, we have developed a solution to keep the standby server’s caches hot. (See my… HTTP, by mysql_slowlogd. This daemon is similar to running `tail -f slow.log`, except that it knows how to follow the…_server:3307/slow | percona-playback –mysql-host 127.0.0.1 –mysql-username playback –mysql-password PaSSwOrd –mysql-schema schema_name –query-log-stdin…
Post: Is Synchronous Replication right for your app?
May 14, 2013 By 18 Comments
…), or work around it with by fsyncing to memory (Battery or capacitor-backed write cache), … MySQL replication from this instance, since MySQL replication is asynchronous. What about semi-sync MySQL … = count + 1 where achievement = ‘killed_troll’; How many players might accomplish this achievement…
Post: How MySQL Query Cache works with Transactions
January 29, 2008 By 5 Comments
As MySQL Manual Says Query Cache works with transactions with Innodb tables but it does not tell you how and with which restrictions. According to my tests it works… one could expect it to work much better: The result set can be retrieved from query cache (for statements both inside and…
Post: Write contentions on the query cache
September 5, 2012 By 5 Comments
… (about 160ms). Of course, I wanted to know more about how MySQL executes this query. So I used commands you’re probably…: why did MySQL need so many accesses to the query cache lock? The answer is in the way the query cache works. Simply stated, the server wants to lock the query cache both…
Post: Query_cache and column level privileges
August 6, 2007 By 5 Comments
…how query_cache works with column level privileges. The question was appeared as we discovered function query_cache…’; and under user ‘vadim’ Before query execution: mysql> show global status like ‘qcache%’; +————————-+———-+ | Variable_name | Value | …
Post: Distro Packages, Pre-built Binaries or Compile Your Own MySQL
September 4, 2012 By 7 Comments
…work, but its only several commands more than installing from your OS or 3rd party repository. Running MySQL…to alter MySQL‘s default behavior i.e. disabling and totally disallowing use of query cache or … at all, if you have problems with how MySQL behaves with your application, maybe it would …
Post: MySQL Connection Timeouts
April 19, 2011 By 4 Comments
… kernel buffer of connection requests on LISTEN socket is overflow – MySQL is not accepting connections as quickly as it needs. There… the problem and do some Math. First lets look into how MySQL accepts connection. There is single main thread which is accepting… thread cache. From this point on MySQL processes network communication in multiple threads and can benefit from multiple cores but this work done…
Post: Why you should ignore MySQL's key cache hit ratio
February 28, 2010 By 28 Comments
… that somewhere around of 99% of advice about tuning MySQL‘s key cache hit ratio is wrong, even when you hear it… the curve and use it as a heuristic for how big your working set is. Set the key_buffer_size to that… and authoritative — the “key cache hit ratio.” This is a shame. When you are new to MySQL, trying to configure my.cnf…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
… with query lookup in cache if not – skips it. Does not support prepared statements and cursors Query Cache works with query text and… as well as how much work is saved by query cache. Now lets speak a bit about Query Cache configuration and mainance. MySQL Manual is… query cache ? Third party application – You can’t change how it works with MySQL to add caching but you can enable query cache so it works faster…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
… you will well learn how your cache behaves. Were even more so interested about writes which show us how many cached writes per second… still worked for MySQL and we specially implemented bunch of tests to ease hardware evaluation for things which are important for MySQL. To prepare small 128MB single file working set we can use the following command…
