Last month at the Boston MySQL User Group, I went through the meanings of INNER, LEFT/RIGHT OUTER, CROSS, NATURAL joins, how to do a FULL OUTER JOIN in MySQL, and what STRAIGHT_JOIN means. I also explained how to recognize when you want those types of joins, and best practices for the semantics of writing joins and design patterns. Subqueries were explained in this session, and some examples of how to think differently so that you end up writing JOINs instead of subqueries. The slides (slightly different from the slides in the video — due to error correction) can be found at http://technocation.org/files/doc/2010_01MySQLJoins.pdf.
OpenSQLCamp was a huge success! Not many folks have blogged about what they learned there….if you missed it, all is not lost. We did take videos of most of the sessions (we only had 3 video cameras, and 4 rooms, and 2 sessions were not recorded).
All the videos have been processed, and I am working on uploading them to YouTube and filling in details for the video descriptions. Not all the videos are up right now….right now all the lightning talks are up.
Last night at the Boston MySQL User Group I presented on how to get a consistent snapshot to build a slave, how to use mk-table-checksum to check for differences between masters and slaves on an ongoing basis, and how to use tools such as mk-table-sync and mysqldump to sync the data if there are any discrepancies.
Singe I’ve got a special press badge this year, I felt I had to do something about it so I decided to make short interview with few people that I’m running into during this Oracle Open World.
I have already blogged about my Sunday’s interviews but I created a Youtube playlist where you can see them all (use arrows on the sides).
So far I interviewed Justin Kestelyn, Richard Foote, Stanley ACE Director, John Kanagaraj, Marko Gralike, Jacco Landlust, Chris Muir, Tim Hall, Steven Feuerstein, Gareth Llewellyn, Doug Burns, Marcel Kratochvil and Gary Goodman. There is one more day left so I’ll trying to do few more.
At the May 2009 Boston MySQL User Group, Giuseppe Maxia of Sun Microsystems gave a presentation about MySQL 5.4 with use cases and benchmarks to show how it outperforms all other current MySQL releases (including the Google patches and the OurDelta/Percona releases).
Welcome back to our videocasts — this is the last video in the series about Oracle RAC Virtual IP’s. I strongly suggest to watch the two previous videos:
I’m writing this post sitting in Vancouver airport but I won’t get into details of my travel complications here, I think it deserves a separate post as it makes a good point for DR plans. :)
What we are looking at during this videocast is how to troubleshoot the connectivity issues that can be caused by VIP’s in Oracle RAC environment and how to diagnose cryptic Oracle error messages using SQL*Net tracing facility on the client side.
We first look at the typical error message “ORA-12545: Connect failed because target host or object does not exist” and how it leads to the IP alias resolution problem that, at first, seems to be easily fixed by changing IP aliases in the connection descriptor to the numerical IP addresses. Then we find out that it’s not enough with Oracle RAC and server-side connection load balancing can still cause you some grief. Read the rest of this entry . . .
The first videocast was quite popular — it has more than 300 views in couple weeks and considering no Hollywood stars were starring in that video and there were no nude scenes, I think it’s fair to say that this format was very much welcomed by the audience.
Today, I’m posting the follow up session on VIP’s (Virtual IP’s) with Oracle RAC. What I demonstrate today is a typical configuration mistake for a RAC databases created with Database Configuration Assistant (DBCA) and what’s the result of such omission.
It’s actually logged as a bug 4338578 on Metalink (thanks to Marcin Przepiorowski for reference). However, I believe it’s not a database issue but (1) misunderstanding how remote listener registration works, (2) documentation bug and (3) DBCA bug.
The init.ora parameter remote_listener defines the list of remote listeners that an instance should register with. The parameter local_listener sets the address for the local listener registration and if not specified, by default it’s hostname and the default port 1521. However, it turns out that the local_listener parameter is used not only for local registration but for something else as well… Read the rest of this entry . . .
“Seeing it once is better than hearing about it a thousand times” — I think this is the closest translation from one Russian proverb. I may add that hearing and seeing might be often better then reading so let me try to start a series of small videocasts about Oracle database technology.
One of the topics that beginners RAC DBA’s (along with network engineers supporting Oracle database infrastructure) are confused about is the Virtual IP usage in Oracle RAC starting from Oracle Clusterware 10g.
With this videocast, I will try to clarify those concerns once and for all. I have embedded the video here in a smaller window so you might want to go directly to YouTube for the full-size version of “Pythian Video: Oracle RAC – Why VIPs“.
This is an experiment for now so let’s see how it goes. Let me know if you find this format useful and don’t forger to rate it on YouTube. Note that if you don’t leave any comments here, I’d never know whether you liked it or not so don’t be shy and comment away…
