It is no secret that bugs related to multithreading–deadlocks, data races, starvations etc–have a big impact on application’s stability and are at the same time hard to find due to their nondeterministic nature. Any tool that makes finding such bugs easier, preferably before anybody is aware of their existence, is very welcome.
Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
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, [...]
Shard-Query EC2 images available
May 11, 2011 By 2 Comments
Infobright and InnoDB AMI images are now available There are now demonstration AMI images for Shard-Query. Each image comes pre-loaded with the data used in the previous Shard-Query blog post. The data in the each image is split into 20 “shards”. This blog post will refer to an EC2 instances as a node from here [...]
Where does HandlerSocket really save you time?
March 16, 2011 By Leave a Comment
HandlerSocket has really generated a lot of interest because of the dual promises of ease-of-use and blazing-fast performance. The performance comes from eliminating CPU consumption. Akira Higuchi’s HandlerSocket presentation from a couple of months back had some really good profile results for libmysql versus libhsclient (starting at slide 15). Somebody in the audience at Percona [...]
Sample datasets for benchmarking and testing
February 1, 2011 By 17 Comments
Sometimes you just need some data to test and stress things. But randomly generated data is awful — it doesn’t have realistic distributions, and it isn’t easy to understand whether your results are meaningful and correct. Real or quasi-real data is best. Whether you’re looking for a couple of megabytes or many terabytes, the following [...]
Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
I am constantly referring to the amazing MySQL manual, especially the option and variable reference table. But just as frequently, I want to look up blog posts on variables, or look for content in the Percona documentation or forums. So I present to you what is now my newest Firefox toolbar bookmark: an option and [...]
Analyzing air traffic performance with InfoBright and MonetDB
October 2, 2009 By 50 Comments
Accidentally me and Baron played with InfoBright (see http://www.mysqlperformanceblog.com/2009/09/29/quick-comparison-of-myisam-infobright-and-monetdb/) this week. And following Baron’s example I also run the same load against MonetDB. Reading comments to Baron’s post I tied to load the same data to LucidDB, but I was not successful in this. I tried to analyze a bigger dataset and I took public [...]
PROCEDURE ANALYSE
March 23, 2009 By 9 Comments
Quite common task during schema review is to find the optimal data type for the column value – for example column is defined as INT but is it really needed or may be SMALLINT or even TINYINT will do instead. Does it contain any NULLs or it can be defined NOT NULL which reduces space [...]
Beware of MySQL Data Truncation
February 7, 2009 By 4 Comments
Here is nice gotcha which I’ve seen many times and which can cause just a minefield for many reasons. Lets say you had a system storing articles and you use article_id as unsigned int. As the time goes and you see you may get over 4 billions of articles you change the type for article_id [...]
Efficient Boolean value storage for Innodb Tables
April 23, 2008 By 6 Comments
Sometimes you have the task of storing multiple of boolean values (yes/now or something similar) in the table and if you get many columns and many rows you may want to store them as efficient way as possible. For MyISAM tables you could use BIT(1) fields which get combined together for efficient storage:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | CREATE TABLE `bbool` ( `b1` bit(1) NOT NULL, `b2` bit(1) NOT NULL, `b3` bit(1) NOT NULL, `b4` bit(1) NOT NULL, `b5` bit(1) NOT NULL, `b6` bit(1) NOT NULL, `b7` bit(1) NOT NULL, `b8` bit(1) NOT NULL, `b9` bit(1) NOT NULL, `b10` bit(1) NOT NULL ) ENGINE=MyISAM mysql> show table status like 'bbool' \G *************************** 1. row *************************** Name: bbool Engine: MyISAM Version: 10 Row_format: Fixed Rows: 10 Avg_row_length: 7 Data_length: 70 Max_data_length: 1970324836974591 Index_length: 1024 Data_free: 0 Auto_increment: NULL Create_time: 2008-04-24 00:41:01 Update_time: 2008-04-24 00:45:40 Check_time: NULL Collation: latin1_swedish_ci Checksum: NULL Create_options: Comment: 1 row in set (0.00 sec) |
