…presentation on “MySQL Query Patterns, Optimized” for Percona MySQL Webinars. If you missed it…after making certain insert/update/delete operations. If you have a dataset …MySQL to scan the `title` table first, grouping by kind_id in index order. This made the first table in the EXPLAIN seem like…
Post: MySQL and the SSB - Part 2 - MyISAM vs InnoDB low concurrency
May 22, 2013 By Leave a Comment
… one query in this flight, Q4.3, which is faster using MyISAM than InnoDB. Like the queries in Flight… does not maintain checksum consistency during regular operations and is not ACID compliant. MyISAM …/mysql56/data basedir=/usr/local/mysql socket=/var/lib/mysql/mysql.sock user=justin innodb_buffer_…
Post: MySQL 5.6 Compatible Percona Toolkit 2.2 Released
March 25, 2013 By 2 Comments
…query-digest 2.2 has fewer options now. Basically, we re-focused it on its primary objective: analyzing MySQL query…In other words, we may change things like the pt-query-digest –output json format in future releases after receiving real-world feedback. In…
Post: Rotating MySQL slow logs safely
April 18, 2013 By 7 Comments
… two of two. Like part one, published Wednesday, this is …can block MySQL because the OS serializes access to the inode during the truncate operation….in addition to logs. Flushing tables can impact running queries. Disable MySQL slow logs during rotation Flushing logs takes time. Meanwhile, queries…
Post: MySQL and Percona Server in LinkBench benchmark
May 8, 2013 By 18 Comments
…. And most likely this symptom is related to BUG#67808. For MySQL 5.6…operations per second for MySQL 5.6.11. Conclusion: In CPU-bounds case MySQL performs quite well, though we can see small performance drop in MySQL…=5000 table-definition-cache=1000 query_cache_size=0 query_cache_type=0 performance_…
Post: Implications of Metadata Locking Changes in MySQL 5.5
February 1, 2013 By 9 Comments
…in the Table Cache, any query to a table that has a DDL operation waiting, will block. Why? Because MySQL…| 2 | bar | dummy_text | +—-+——+————+ 2 rows in set (53.78 sec) session10 > show status like ‘Open%tables’; +—————+——-+ | Variable_name | Value | …
Post: Should we give a MySQL Query Cache a second chance ?
April 10, 2011 By 64 Comments
…. I’d like to see support for something like SQL_CACHE_TTL=60 to specify we’re OK to get query result which… how exactly MySQL Query Cache is working in many cases. This however can be improved and data about Query Cache content and operation can be presented as some INFORMATION_SCHEMA tables. Self Refresh MySQL Query Cache causes not…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 9 Comments
… lag. Same may happen with operating system and other system software involved. In could be even system which queries mysql. I’ve seen monitoring updates which would add excessively expensive and frequent query on information… which runs on devices themselves now, so watch for things like firmware updates bios updates etc, which even though not frequent…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
… actually quite simple in its operation. It will…querying, even during refresh. A complete refresh type view can use non-deterministic functions like NOW(). In…in descending order: mysql> call flexviews.create( -> ‘demo’,'dashboard_top_customers’,'COMPLETE’); Query OK, 1 row affected (0.00 sec) mysql…
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…operate in “Cache everything” mode. In certain caches you might want to cache only some of the queries – in this case you can set query… load, like many personal application query cache…
