…interesting problem – query joining about 20 tables (thank you ORM by joining all tables connected with …tables, – it is not clear how far from optimal plans do we get by using a greedy search. From the same…of tables, 7) essentially limiting search depth to no more than 7 at which complexity is …
Post: Performance impact of complex queries
January 17, 2007 By 11 Comments
…complex queries on large data sets(ie some large aggregate queries) and batch jobs. It is not rare to see queries… you use Innodb tables and so do not suffer from table locks reporting queries can affect web site… database version from the backup or LVM snapshot of current database with same results. …
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 22 Comments
…table `ontime_fact` is created by joining the newly constructed dimension table tables to the staging tables, omitting the dimension columns from… 11 queries. This same SQL script was used in the Shard-Query tests. … post. Complex queries Shard-Query was tested with the simple single table version of …
Post: MySQL Query Cache
July 27, 2006 By 69 Comments
…query cache offering about double performance for simple queries with select done by primary key, obviously there is no upper boundary – Very complex queries…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
… possible scenario for MyISAM tables. Now if we take the same hard drive for fully…table. The times for full table scan vs range scan by index: mysql> select count(pad) from large;… compose the complex object which was previously normalized to several tables or perform complex queries finding …
Post: MySQL VIEW as performance troublemaker
August 12, 2007 By 53 Comments
…from the table by the key we think this is simple query, while can be real monster instead with complexity…back counts for each user and can simply query from that table restricting by user_id. If this … such query and time for the query which fetches everything from the VIEW – it is almost the same …
Post: Recovering Innodb table Corruption
July 4, 2008 By 19 Comments
…table I am getting: mysql> check table test; ERROR 2013 (HY000): Lost connection to MySQL server during query mysql> check table test; +———–+——-+———-+———-+ | Table…from simple Innodb Table Corruption. In more complex…
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 63 Comments
… to reduce complexity dramatically. Fast Invalidation Right now when you update the table all queries have to be invalidated from the query cache… … anyway. Smart Query Matching Query Cache requires queries to be exactly the same which does not work well with queries containing dynamic comments …
Post: High-Performance Click Analysis with MySQL
December 22, 2008 By 13 Comments
…, in the next row.” So we’re storing all the same data, right? Logically, yes; physically, no. Those values that we… to write a little more complex queries, but that’s often justified by a large reduction in table size. I sort of stumbled… it has a custom table, which is really constructed behind the scenes from the name-value tables in a complex query with many joins. I…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…tables whose .frm files exist but have been dropped from InnoDB, for example. (The INFORMATION_SCHEMA query…complex…
