…with Merge tables for example – creating and accessing few merge tables with 1000 of subtables will likely cause your MySQL…Another possibility is to use queries which use large temporary tables…
Post: Air traffic queries in InfiniDB: early alpha
November 2, 2009 By 19 Comments
…Query Q4: mysql> SELECT Carrier, count(*) FROM ontime WHERE DepDelay > 10 AND YearD=2007 GROUP BY Carrier ORDER BY 2 DESC; I had another surprise with query…Query Q9: Q9: select Year ,count(*) as c1 from ontime group by Year; Time: 9.54 sec Ok, so there is summary table with queries…
Post: Air traffic queries in LucidDB
October 26, 2009 By 20 Comments
…Another interesting metric is datasize after load. In LucidDB db file after load takes 9.3GB. UPDATE 27-Oct-2009 From metadata table…MySQL via JDBC driver) just in SQL queries (compare with…
Post: Sphinx 0.9.8 is released just in time for OSCON 2008
July 20, 2008 By 2 Comments
…Another interesting point is Sphinx grouping performance. For example on the same 15M document collection counting…MySQL with best covering index (so no temporary table or sorting is needed for group by). Note that with…
Post: ANALYZE: MyISAM vs Innodb
September 3, 2008 By 9 Comments
…tables and see how values change: mysql> update antest set c=NULL; Query…table with same data though we can see Innodb stats are a bit off from reality too. MySQL version note: This is from MySQL…
Post: Joining on range? Wrong!
May 17, 2010 By 10 Comments
…tables with enough data to serve our purpose. Our hypothetical sales query…from join one way or another. For our example query…UPDATE items_ordered SET itm_order_date = DATE(itm_order_timestamp); Now the rewritten query: EXPLAIN SELECT COUNT(1) FROM…8569, #19548). Some replies from MySQL indicate this …
Post: The perils of InnoDB with Debian and startup scripts
January 28, 2009 By 13 Comments
…tables, InnoDB uses over 3.5G of memory for its data dictionary (the subject for another…Updating | update…from the last 15 seconds ———- SEMAPHORES ———- OS WAIT ARRAY INFO: reservation count 39125236, signal count…mysql tables in use 7, locked 0 MySQL thread id 6424, query…
Post: Just do the math!
July 6, 2009 By 4 Comments
…things not working any more with response times for individual queries taking half an hour …like this ? Say you have query like “SELECT page,count(*) cnt FROM logs GROUP BY page … Another aspect is the temporary table – the number of rows MySQL can insert/update depends on whenever temporary table…
Post: Sphinx: Going Beyond full text search
July 23, 2007 By 18 Comments
… thousands of search queries per day. The count of forum posts…mysql.com” links were stored in one table group and “google.co.uk” on another… lot of resources to update or periodically build for …with Sphinx. This also uses fair amount of tricks using fake full text search to retrieve all posts from…
