Blog
Understanding InnoDB MVCC
Multi versioning concurrency control (MVCC) is a database design theory that enables relational databases to support concurrency, or more simply multiple user access to common data in your database. In MySQL the InnoDB storage engine provides MVCC, row-level locking, full ACID compliance as well as other features.
Killing my softly with QUERY
The MySQL KILL command as the name suggests kills queries that are running. After identifying the Id using the SHOW PROCESSLIST command, the User of the connection/thread or a database user with SUPER privileges can execute KILL [id]; to remove the connection/thread.
Installing Perl RRD module – RRDs.pm
Perform a quick check if the module is available. $ perl -MRRDs -le 'print q(ok!)' Can't locate RRDs.pm in @INC (@INC contains: /usr/lib64/perl5/site_perl/5.8.8/x86_64-linux-thread-multi /usr/lib64/perl5/site_perl/5.8.7/x86_64-linux-thread-multi /usr/lib64/perl5/site_perl/5.8.6/x86_64-linux-thread-multi /usr/lib64/perl5/site_perl/5.8.5/x86_64-linux-thread-multi /usr/lib/perl5/site_perl/5.8.8 /usr/lib/perl5/site_perl/5.8.7 /usr/lib/perl5/site_perl/5.8.6 /usr/lib/perl5/site_perl/5.8.5 /usr/lib/perl5/site_perl /usr/lib64/perl5/vendor_perl/5.
An important Drizzle/MySQL difference
There are many features that are similar in MySQL and Drizzle. There are also many that are not. I’ve previously discussed topics like Datatypes and tables , SQL_MODE and SHOW .
The confusion over global and session status
I was trying to demonstrate to a client how to monitor queries that generate internal temporary tables. With an EXPLAIN plan you see ‘Creating temporary’. Within MySQL you can use the SHOW STATUS to look at queries that create temporary tables.
Benchmarking Drizzle with MyBench(DBD::drizzle)
With thanks to Patrick Galbraith and his DBD::drizzle 0.200 I am now able to test client benchmarks side by side with MySQL and Drizzle. For simple benchmarking with clients, generally when I have little time, I use a simple Perl framework mybench .
Verifying MySQL Replication in action
There is a very simple test to show MySQL replication in action and to also better understand the basics of MySQL Replication. With a configured MySQL environment we can run the following test on your MySQL master, and monitor the MySQL slave.
MiFi Installation woes
As I mentioned in MiFi Introduction I took the plunge and purchased a Verizon MiFi . I got this under a 2 year contract for $149.99 and $59.99 per month for 5GB of traffic.
MiFi Introduction
My first news of the Verizon MiFi was via Twitter when @DonMacAskill said “Think my iPhone 3G via MiFi is faster than AT&T 3G. Should I carry both all the time now?
Using statpack with SHOW STATUS
Mark Leith, on of the MySQL Support Team managers wrote some time ago a very nice utility I use often called Statpack . My use of Statpack is very simple. Take two snaphots of SHOW GLOBAL STATUS and compare to produce a text based version of the statistics.
The value of multi insert values
Baron got a great amount of response from his 50 things to know before migrating Oracle to MySQL . I’m glad I invited him as a fellow MySQL colleague to my presentation to the Federal Government on Best Practices for Migrating to MySQL from Oracle and SQL Server for his inspiration.
What is max_tmp_tables?
Recently I came across another configuration option I’d not heard of before. I profess to not know them all, however I do know when I find something unusual. If you are a beginner DBA, learn what is normal and expected, and identify what is out of the normal, investigate, research and question if necessary.
O’Reilly Twitter Boot Camp a success
The first O’Reilly Twitter Boot Camp – #OTBC was held in New York as a pre cursor to 140 Characters Conference – #140conf on Monday 15th June, 2009. With opening and closing keynotes were like matching bookends of The Twitter Book #twitterbook offered to all attendees and authored by the keynoters @timoreilly and @SarahM .
Wafflecloud with cream
I have been working recently with Matt Yonkovit to get Waffle Grid cloud enabled with Amazon Web Services (AWS) . An initial version of Waffle Grid Cream – Version 0.5 release is now available.