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Curious Case with MySQL Replication

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..

A NoCOUG to Remember

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.

RDBMS Online Patching

If you support Oracle RDBMS 11.2.0.2 and want to zero downtime applying patches to databases then it is time to have a look at new possibility of Online Patching delivered with 11.2.0.2 version and described here.

Alter Waiting on Select Statement to Complete

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.

Log Buffer #235, A Carnival of the Vanities for DBAs

Oracle has launched Java 7, Steve Jobs has resigned, IBM has made new alignments with HP and so on. The industry is buzzing with the breaking news while one thing is rest assured that the brightest and most innovative days are ahead of the IT industry, and so blogging is anticipating some thrilling times ahead and so are the Log Buffer Editions. To get a peek of future, lets savor Log Buffer #235.

Viewing RMAN Jobs Status and Output

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.

Log Buffer #234, A Carnival of the Vanities for DBAs

Well like all good things, summer is also ending and its closing days are rapidly approaching. For most of the database techies, there is nothing to get remorseful, because they are thrilled to be back in full flow managing and loving their databases. They are gearing up, refreshing up, re-evaluating and reassessing themselves and also blogging about it. This Log Buffer enjoys the last days of summer in this Log Buffer #234.

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