Posts Categorized: Technical Blog
I’ve been following the development of Tungsten Replicator for quiet some time now, and recently was fortunate enough to find the time to take a look at the product in more detail. Here’s my review, enjoy.
MySQL Replication is a powerful tool and it’s hard to find a production system not using it. On the other hand debugging replication issues can be very hard and time consuming. Especially if your replication setup is not straightforward and you are using filtering of some kind. Let’s look at an issue I had..
When I found out that NoCOUG had accepted my abstract, “Oracle 11g: Learning to Love the ADR”, I was both ecstatic and terrified. This meant that I actually had to prepare the presentation and speak in front of peers. Surely they would throw me into San Francisco Bay if I didn’t bring my A-game, so I set out to do just that.
A few days ago, we faced an interesting problem on one of our customer’s slave mysqld servers. An Alter for adding a new column was run on master server took 542 seconds where as it took few hours on the slave server to complete due to a SELECT blocking the Alter was not allowed to complete. What happened in this situation was: ALTER started first, then concurrent SELECT started on the same table, when ALTER finished copy to a temp table it tried to RENAME table, but failed to get global lock on data dictionary. All the threads that started after this point had to wait on ALTER to finish.
Backup jobs can be scheduled in many different ways (crontab, Grid Control, Scheduled Tasks, etc) and finding the log file may be tricky if you don’t know the environment well. Furthermore, log files may also have already been overwritten by the next backup or simply just deleted. An alternative way of accessing that information, thus, may come handy. Fortunately, RMAN keeps the backup metadata around for some time and it can be accessed through the database’s V$ views. Obviously, if you need this information because your database just crashed and needs to be restored, the method described here is useless.
Pythian’s Oracle ACE, Fahd Mirza appears in this month’s Community: Peer-to-Peer review “In With the New”, as published in the September/October 2011 issue of Oracle Magazine. Fahd states that “Oracle Exadata Database Machine” has most changed his life – changing the game, and setting very high standards of performance, support, scalability, reliability and unification. Shout out to Fahd from your peers at Pythian!
t’s a busy summer at Pythian, with our continuing wave of speaking sessions at upcoming community and regional industry events. Coming to a city near you, watch for Pythian presenting hot Oracle and Microsoft SQL Server database topics.
Just a few days ago I received a reminder email from Burke Scheld for the “AUSOUG National Conference Series – Perth 2011 – Call for Papers”. I had an event-related conversation with several Oracle guys in my professional networks and the answers I received triggered this blog post. Some of the very good Oracle professionals I personally respect said “…I am not sure what I would get out of it …” or “…I haven’t done anything exciting for the last FEW MONTHS …”. The answers I received shocked me a bit.
On many of our clients, we have a need to run XtraBackup as a regular OS user. Aside from running into the issue where tar4ibd was not provided with Percona’s xtrabackup-1.6.2.tar.gz package, our main issues have been with permissions when attempting a streaming backup. Here is the innobackupex command that works for us.
We have incident reporting procedures at Pythian. This incident report was sent just recently internally at Pythian. We learned some good lessons from it so I hope it would be useful to the community as well – As part of our incident management process, you will find below a summary of the details from the incident that occurred on July 29th at 3PM EDT. Overview: Pythian employees were de-motivated by the lack of refreshments on Friday afternoon