… the size of the partitions, the whole partition can be cached, as opposed to a single table, where probably only recently read records will be cached, resulting in more disc reads. 2. If you need to…. If you do queries on any other column, these could easily be quicker on a partitioned table, as Mysql can fire off…
Comment: Why MySQL Performance at Low Concurrency is Important
March 31, 2013 By 8 Comments
…/03/mysql-56-single-threaded-read-only.html. All of the conclusions assume a benchmark with fast (100 to 200 usecs) queries… a big win * 5.6 was ~9% slower for a cached database whether or not the PS was disabled
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
… saved by query cache. Now lets speak a bit about Query Cache configuration and mainance. MySQL Manual is pretty good on this: Query Cache Query Cache Status Query Cache Configuration I would just mention couple of points – as protection from one query wiping…
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 64 Comments
… as MySQL Query Cache is most useful for complex expensive queries, for which tracking exact rows used from query syntax may be hard. Query Cache Storage Engines MySQL Query Cache now stores queries in local…
Post: MySQL caching methods and tips
April 4, 2011 By 5 Comments
… some of the most common cache methods for MySQL. Popular cache methods The MySQL query cache When the query cache is enabled, MySQL examines each query to see if the contents have been stored in the query cache…
Post: Cache Performance Comparison
August 9, 2006 By 74 Comments
… envinronment are: Cache Type Cache Gets/sec Array Cache 365000 APC Cache 98000 File Cache 27000 Memcached Cache (TCP/IP) 12200 MySQL Query Cache (TCP/IP) 9900 MySQL Query Cache (Unix Socket… file cache to work you need file named “test” containing “MyTestString” 2) You need to create table test.test for MySQL Cache to…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
… bug: http://bugs.mysql.com/bug.php?id=67647 Metadata locking behaves differently for queries that are serviced from the Query Cache, let’s… in the Table Cache, any query to a table that has a DDL operation waiting, will block. Why? Because MySQL sees that the old entries in the Table Cache have to be invalidated, and any query that accesses the…
Post: Write contentions on the query cache
September 5, 2012 By 5 Comments
… for query cache lock | 0.000004 | | Waiting on query cache mutex | 0.000002 | | Sending data | 0.003407 | | Waiting for query cache lock | 0.000003 | | Waiting on query cache… was: why did MySQL need so many accesses to the query cache lock? The answer is in the way the query cache works. Simply stated…
Post: MySQL 5.5 and MySQL 5.6 default variable values differences
February 21, 2013 By 8 Comments
… days. query_cache_type and query_cache_size. The behavior is “no cache” by default still but it is achieved differently now. The query_cache_type is now off by default with default size of 1MB while in MySQL 5.5 and before it was “ON” by default with query cache size of 0 which makes it disabled. I wish query_cache…
Post: Return of the Query Cache, win a Percona Live ticket
August 26, 2011 By 4 Comments
… Live London ticket! But first, what’s new with the MySQL query cache? You may know that it still has the same fundamental… was still 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 made…
