… (user or cart object built from several queries) Infrequently changing data (configurations, etc) In … In a nutshell, here is how one would start the memcached plugin: mysql>…benchmark: // Identical config/code for memcached vs InnoDB $frontendOpts = array( ‘caching’ => true, ‘lifetime’ => 3600, ‘…
Post: More on MySQL transaction descriptors optimization
April 26, 2013 By Leave a Comment
…results we have rerun tests on several our boxes. You can find setup…a single-node (on the left) vs. two-node (on the right) configuration….explanation, I’d like to highlight one aspect of the descriptors optimization …updates to the database, all SELECT queries, even those participating in read-only …
Post: Write contentions on the query cache
September 5, 2012 By 5 Comments
… into the cache. When writing, locking can occur several times: the server sends results to the cache … for a query, you should suspect either some change in data access pattern (reads on disk vs reads …have 2 lines showing waits on the query cache lock instead of one in the output of SHOW PROFILE? …
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 31 Comments
…,30) are more complicated as this is in fact several separate index lookups. So we spoke about how MySQL…just 2 separate indexes ? I will either use just one of them to look up the data (and check… use them for this query. The query takes 3370ms if this plan is used. Note the query takes about 5 times…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
…table. The times for full table scan vs range scan by index: mysql> select …issues IO requests one by one for query execution, which means if single query execution time is …query into several, run in parallel and aggregate result sets. So if you’re dealing with large data sets and complex queries…
Post: Economics of Performance Optimization
March 13, 2008 By 9 Comments
… . First lets talk about optimizing application vs getting better hardware. With application …throughput. If single user CPU bound query takes 30 seconds you unlikely … to scale out to the several boxes. If you do this …admin overhead) if you have just one server optimizing your application very modest…
Post: Full Text Search Webinar Questions Followup
August 24, 2012 By 5 Comments
… webinar this week to give an overview of several Full Text Search solutions and compare their performance. …yes, which one seems the best? No, I didn’t compare relevancy. I was focused solely on query response … where I announced the webinar: We evaluated MySQL vs Solr. I was able to index all the…
Post: Heikki Tuuri answers to Innodb questions, Part II
November 4, 2007 By 13 Comments
… PZ: I should note MySQL 5.0 vs 4.1 has a lot of performance…: There have been several MySQL bugs opened about multi-core scalability (concurrent queries, autoincrement, concurrent inserts, instrumentation…on the OS version. In our tests, removing one bottleneck moves the contention to another place. …
Post: Percona XtraDB Cluster Feature 1: High Availability
January 17, 2012 By 20 Comments
…queries to any of the nodes Drawbacks: Overhead of joining new node. The new node has to copy full dataset from one…throughput when you run write traffic to 2 nodes vs all traffic to 1 node, but you can’…still have to go on all nodes. You have several duplicates of data. For 3 nodes – 3 duplicates …
Post: The Doom of Multiple Storage Engines
May 8, 2010 By 22 Comments
…if you look at In Memory storage engines vs Distributed ones. Trying to handle all different cases in …complications and performance overhead. MySQL has to do several fsync() calls per transaction commit to be …allows you using multiple storage engines in the query you need to test all kinds of …
