… 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… each time (like a memcache miss) or they must be updated. Updating the summary tables efficiently is a hard problem to solve…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
…_F BINLOG ‘ L5cLURMBAAAALwAAAAUDAAAAABEAAAAAAAEABHRlc3QABHRlc3QAAwMD/gL+CQY= L5cLURgBAAAAOAAAAD0DAAAAABEAAAAAAAEAA///+AIAAAAAAAAAA2JhcvgCAAAAAAAAAANob3A= ‘/*!*/; ### UPDATE test.test ### WHERE ### @1=2 /* INT meta…will block. Why? Because MySQL sees that the old entries in the Table Cache have to be …
Post: Troubleshooting MySQL Memory Usage
March 21, 2012 By 5 Comments
…Check for Table Cache Related Allocations There are cases when MySQL will allocate a lot of memory for table cache, especially if … 0 DATA_LENGTH: 16384 INDEX_LENGTH: 0 CREATE_TIME: NULL UPDATE_TIME: NULL *************************** 2. row *************************** SESSION_ID: 7234 TABLE_SCHEMA: …
Post: Thoughts on MySQL Replication
July 7, 2006 By 18 Comments
… used only for absolutely critical updates. Third one is to use cache – something like memcached, besides pure caching it can be used to… to have data you’re accessing to be cached in memory by MySQL cache or OS cache. As slaves replicate the same data and often queried in random or round robin fashion their cache would…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 9 Comments
… might be different and hence cache content. Replication Traffic Changes Changing in the replication traffic (what updates are being replicated) are frequent… involved. In could be even system which queries mysql. I’ve seen monitoring updates which would add excessively expensive and frequent query…
Post: Cache Performance Comparison
August 9, 2006 By 74 Comments
… you do not get cache invalidated with each update) and ability to cache composed objects which may correspond to multiple MySQL queries. On Selecting from the table I should note MySQL… file cache to work you need file named “test” containing “MyTestString” 2) You need to create table test.test for MySQL Cache to…
Post: Distro Packages, Pre-built Binaries or Compile Your Own MySQL
September 4, 2012 By 7 Comments
… can be as easy as stopping MySQL, updating symlinks or your my.cnf basedir, starting MySQL and running mysql_upgrade. Unlike package managers, you do not have to worry about accidentally updating from one version… patches, need to alter MySQL‘s default behavior i.e. disabling and totally disallowing use of query cache or increasing maximum total…
Post: Is there room for more MySQL IO Optimization?
January 3, 2013 By 11 Comments
… cache I would normally have on database server for those things which need to be cached — system files, binary log, FRM files, MySQL MyISAM system tables etc. Starting MySQL 5.5 MySQL uses asynchronous IO…_increment: NULL Create_time: 2012-12-31 16:24:54 Update_time: NULL Check_time: NULL Collation: utf8_general_ci Checksum…
Post: Review of MySQL 5.6 Defaults Changes
October 8, 2012 By 10 Comments
…the great summary of defaults changes in MySQL 5.6 compared to MySQL 5.5 In general there are …even more would be good default. query_cache_size = 1M Query cache remains off by default but default size …and sync_relay_log_info settings. James also promises updated sample my.cnf and getting rid of old …
Post: Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2
May 3, 2011 By 13 Comments
…barracuda innodb_file_per_table max_connections=2000 table_cache=2000 Percona Server 5.1 Results For better …not to penalize further TPS. MySQL 5.6.2 Results Now let’s test MySQL 5.6.2. It is…of the scripts and results) and here are the updated 5.6.2 results. The difference against baseline 5…
