… started from in-memory data size and expect gradual performance decrease as database size grows you may be surprised by serve… query runs as single thread (with exeption of MySQL Cluster) and MySQL issues IO requests one by one for query execution, which means if single query execution time…
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
… available on 64 bit instances. MySQL will fail to start on a micro instance, simply decrease the values in the /… time). $ echo “select count(*) from ontime_fact;” | ./run_query Array ( [count(*)] => 135125787 ) 1 rows returned (0.084244966506958s, 0.078309059143066s, 0.0059359073638916s) Execute…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
…MySQL Query Cache is the same as Oracle Query Cache – meaning cache where execution plans are cached. MySQL Query…query cache. If you need larger queries to be cached you might increase it, if you most important queries are smaller you can decrease…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… the workload is IO bound, the query time is decreased from ~11min to under a minute. The query time is reduced further when the buffer…, then query times remain under a minute. So when the correct query execution plan is not used, there is no difference in query times between MySQL 5…
Post: MySQL caching methods and tips
April 4, 2011 By 5 Comments
…time. Using less computing resources, particularly in the cloud, results in decreased…time. These cache stampedes are essentially the cause of the unpredictable performance of the MySQL query…
Post: Find and remove duplicate indexes
June 20, 2012 By 9 Comments
… name and MySQL will avoid to create duplicate indexes: mysql> alter table t add index key_for_first_name(name); Query OK, 0… queries with tools like pt-upgrade. As we saw in previous sections sometimes redundant keys can help us to improve the execution time and decrease the size of the data read.
Post: MySQL Server Memory Usage
May 17, 2006 By 21 Comments
…current settings and increase/decrease values appropriately. Some may…: List of rarely considered MySQL Server Memory Requirements …query executions Query Parsing and optimization needs memory. This is usually small to be ignored but certain queries… remove queries. Blobs may require 3x time of memory…
Comment: mysql-proxy, urgh performance and scalability ?
June 10, 2009 By 44 Comments
…0.7 performance is: The shorter the query execution time, the higher the overhead will be. …query (because the result packets will arrive very shortly after the query was issued, decreasing the time it can spend on other queries…, please report them at http://bugs.mysql.com in the Proxy component. If …
Post: Data mart or data warehouse?
July 15, 2010 By 14 Comments
… years, months, quarters, or other time dimension attributes. This aids in …and category, but performance tends to decrease as the number of dimensions increases…query execution, clustered tables and materialized views. These features make working with a star schema much easier than it may be on MySQL…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
… InnoDB 442 mysql tables in use 1, locked 0 MySQL thread id 8079, query id 728899 localhost… For certain workloads it may help to decrease the time thread waits before it enters the … buffers. Normal reads originated from query executions are executed by threads running queries. On Unix/Linux you will…
