…=%s”,$name) – wrapper will detect query is being called with multiple parameters and will perform needed checks and query rewriting. You… doing so. Using multiple tables gives some very important benefits – your data becomes managable, your ALTER TABLE or OPTIMIZE TABLE now locks… your data however it does not always bring good performance. Joins are expensive and you can often do much better with…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
… The refresh algorithm computes changes in multiple transactions. After each transaction it …mview_table_alias: o mview_join_condition: NULL mview_join_order: 999 *************************** 2. row ***************************…be more expensive. This is an optimization which is required to efficiently …
Post: Using Flexviews - part one, introduction to materialized views
March 23, 2011 By 3 Comments
… a performance optimization because: The contents of the result set are computed each time the view is accessed. If multiple statements access… joined together and pre-aggregated, CPU and memory usage may be reduced compared to computing the results. You can often generate multiple…. And some drawbacks: Not all SQL syntax supported (no outer join), no non-deterministic functions, etc. There is overhead for change…
Post: Heikki Tuuri Innodb answers - Part I
October 26, 2007 By 19 Comments
… of replacement policy optimizations possible. Q8: How do you assess current state of Innodb scalability with multiple threads and multiple concurrent transactions ? HT… denormalized database (for example, if ORDER and ORDERLINE tables are joined to form a single table), it might make sense for…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
…time=1000 on MySQL 5.5.30 and testing multiple buffer pools on MySQL 5.5.30. Finally, …| 0.001000 | 0 | 0 | 0 | 0 | 3 | 3 | | 8 | optimizing | 0.000048 | 0.000048 | 0.000000 | 0.000000 | 0 … = d_datekey join customer on lo_custkey = c_customerkey join supplier on lo_suppkey = s_suppkey join part on …
Post: Missing Data - rows used to generate result set
July 20, 2008 By 15 Comments
… optimize query anyway. The question of optimizing number of rows accessed is what would be the optimal number indicating query is typically well optimized… to reach for small fraction of queries. If you’re joining multiple tables or if you have GROUP BY query the number… results set which clearly puts query as optimization candidate. It is not always possible to optimize queries so the number of rows…
Comment: How we work on High Performance MySQL Second Edition
November 19, 2007 By 12 Comments
… on the layout, hardware/software considerations, and how the query optimizer engine works were very good. However, I felt the chapter… that is filtered by multiple fields in the foreign table and contacts table. Examples of when to use joins over the where… enjoy a discussion of a query that is filtering on multiple fields and how you would build an index for it…
Post: MariaDB 5.3 is released as GA!
March 5, 2012 By 17 Comments
…queries through speedier joins, faster subqueries, and elimination of useless tables in joins Thread pooling and…support, as well as a lot of optimizer improvements. Even the standard MySQL 5.5…, improvements to partitioning, and the addition of multiple InnoDB buffer pools. Best of all, MariaDB…
Post: Is your MySQL Application having Busy IO by Oracle Measures ?
January 8, 2012 By 1 Comment
… would be exceptional for traditional MySQL as MySQL optimizer with its nested loops joins does not favor sequential scans even for analytic… can be used for free we do not need to optimize the hardware for license costs. With Oracle license costs based… get a lot better performance with multiple MySQL instances on powerful storage. When you move to multiple instances and you have to…
Post: Watch out for Marketing benchmarks
August 23, 2006 By 7 Comments
….0 a lot of great features were implemented and new optimizations being added which made certain things much faster, sometimes hundreds… when it become few percent slower (especially due to handling multiple character sets). Of course I would not say it is… subqueries, cases when hash or sort merge join is needed and in many other advanced optimizer features. I can help in many…
