Monthly Archives - February 2013

CentOS 5.8 users: your UTF-8 data is in peril with Perl MySQL

CentOS 5.8 and earlier use Perl module DBD::mysql v3.0007 which has a bug that causes Perl not to flag UTF-8 data as being UTF-8.  Presuming that the MySQL table/column is using UTF-8, and the Perl MySQL connection is also using UTF-8, then a correct system returns:

PV = 0x9573840 “\343\203\213 \303\250″\0 [UTF8 “\x{30cb} \x{e8}”]
That’s a […]

Read more

MySQL 5.5 and MySQL 5.6 default variable values differences

As the part of analyzing surprising MySQL 5.5 vs MySQL 5.6 performance results I’ve been looking at changes to default variable values. To do that I’ve loaded the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query:

Shell

mysql [localhost] {msandbox} (test) > select var55.variable_name,left(var55.variable_value,40) value55, left(var56.variable_value,40) var56 from […]

Read more

Solving RPM installation conflicts in CentOS 5 and CentOS 6

Lately we’ve had many reports of the RPM packages for CentOS 5 (mostly) and CentOS 6 having issues when installing different combinations of our products, particularly with Percona Toolkit for MySQL. Examples of bugs related to these issues are lp:1031427 and lp:1051874.
These problems arise when trying to install a package from the distribution that […]

Read more

NoSQL is Great, But You Still Need Indexes

I’ve said it before, and, as is the nature of these things, I’ll almost certainly say it again: your database performance is only as good as your indexes.
That’s the grand thesis, so what does that mean? In any DB system — SQL, NoSQL, NewSQL, PostSQL, … — data gets ingested and organized. […]

Read more

Mystery Performance Variance with MySQL Restarts

Based on a lot of surprising comments about my MySQL 5.5 vs 5.6 performance post I decided to perform deeper investigation to see where my results could go possibly wrong. I had set up everything to be as simple as possible to get maximally repeatable results. I did Read Only ran which is typically […]

Read more

Analyzing Slow Query Table in MySQL 5.6

Analyzing SQL Queries with Percona Toolkit, Feb. 25-28, 9-11 a.m. PST
Next week I’m teaching an online Percona Training class, called Analyzing SQL Queries with Percona Toolkit.  This is a guided tour of best practices for pt-query-digest, the best tool for evaluating where your database response time is being spent.
This month we saw the GA release […]

Read more

Percona MySQL University comes to Toronto on March 22

Percona CEO Peter Zaitsev leads a track at the inaugural Percona MySQL University event in Raleigh, N.C. on Jan. 29, 2013.
Following our events in Raleigh, Montevideo, Buenos Aires, Percona MySQL University comes to Toronto on March 22nd.
This is going to our most dense event yet, absolutely packed with information. Even though we have just […]

Read more

Percona MySQL Webinar: Really Large Queries: Advanced Optimization Techniques, Feb. 27

Really Large Queries: Advanced Optimization Techniques: Wednesday, February 27, 2013 10 a.m. PST
Do you have a query you never dared to touch?
Do you know it’s bad, but it’s needed?
Does it fit your screen?
Does it really have to be that expensive?
Do you want to do something about it?
During the next Percona webinar on February 27, […]

Read more

Using MySQL Sandbox with Percona Server

One of the most useful tools if you’re working with multiple versions of MySQL Servers is MySQL Sandbox which allows you to maintain many different versions of MySQL, Percona Server, MariaDB. If you’re just working with single sandbox you can just use MySQL Sandbox in its most basic way and it will work:

Shell

root@smt2:~/sandboxes# make_sandbox […]

Read more