Intel came on PCI-e SSD market with their Intel SSD 910 card. With a slogan “The ultimate data center SSD” I assume Intel targets rather a server grade hardware, not consumer level. I’ve got one of this card into our lab. I should say it is very price competitive, comparing with other enterprise level PCIe [...]
Visualization tools for pt-query-digest tables
August 31, 2012 By 6 Comments
When you process MySQL slow query logs using pt-query-digest you can store samples of each query into query_review table and historical values for review trend analysis into query_review_history table. But it could be difficult to easily browse those tables without a good GUI tool. For the visual browsing of tables created by pt-query-digest you may [...]
Differences between READ-COMMITTED and REPEATABLE-READ transaction isolation levels
August 28, 2012 By 3 Comments
As an instructor with Percona I’m sometimes asked about the differences between the READ COMMITTED and REPEATABLE READ transaction isolation levels. There are a few differences between READ-COMMITTED and REPEATABLE-READ, and they are all related to locking.
Can we improve MySQL variable handling ?
February 18, 2012 By 8 Comments
MySQL Settings (also known as Server Variables) have interesting property. When you set variable in running server this change is not persisted in any way and server will be back to old value upon restart. MySQL also does not have option to re-read config file without restarting as some other software so approach to change [...]
MySQL opening .frm even when table is in table definition cache
November 21, 2011 By 8 Comments
or… “the case of Stewart recognizing parameters to the read() system call in strace output”. Last week, a colleague asked a question: I have an instance of MySQL with 100 tables and the table_definition_cache set to 1000. My understanding of this is that MySQL won’t revert to opening the FRM files to read the table [...]
Fishing with dynamite, brought to you by the randgen and dbqp
November 16, 2011 By Leave a Comment
I tend to speak highly of the random query generator as a testing tool and thought I would share a story that shows how it can really shine. At our recent dev team meeting, we spent approximately 30 minutes of hack time to produce test cases for 3 rather hard to duplicate bugs. Of course, [...]
Preprocessing Data
August 8, 2011 By 3 Comments
There are many ways of improving response times for users. There are some people that spend a lot of time, energy and money on trying to have the application respond as fast as possible at the time when the users made the request. Those people may miss out on an opportunity to do some or [...]
Flexviews is a working scalable database transactional memory example
May 19, 2011 By 3 Comments
http://Flexvie.ws fully implements a method for creating materialized views for MySQL data sets. The tool is for MySQL, but the methods are database agnostic. A materialized view is an analogue of software transactional memory. You can think of this as database transactional memory, or as database state distributed over time, but in an easy way [...]
Distributed Set Processing with Shard-Query
May 14, 2011 By 27 Comments
Can Shard-Query scale to 20 nodes? Peter asked this question in comments to to my previous Shard-Query benchmark. Actually he asked if it could scale to 50, but testing 20 was all I could due to to EC2 and time limits. I think the results at 20 nodes are very useful to understand the performance: [...]
Percona’s Sessions at the O’Reilly MySQL Conference and Expo
April 7, 2011 By Leave a Comment
I just realized that we haven’t blogged a list of our sessions at the O’Reilly MySQL Conference and Expo (#mysqlconf) yet. Here is a hopefully complete list.
