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…
More than a month has passed since Sydney Oracle Meetup #2. We shot some video, but it took me a while to process it and publish a few interesting pieces, but I finally got it all.
Ric Van Dyke‘s presentation on tuning SQL queries using 10046 trace is available on the SOM website in the Files section (you must be a member). However, there were no material from Tanel Poder‘s session — it’s title started with “Zero Slides…” and Tanel demonstrated live some of his secrets of productivity in Oracle troubleshooting. Luckily, my colleague, Andrey Goryunov, managed to shoot some of it on the video and I’m publishing here a couple fragments on the visualization of Oracle performance troubleshooting.
Make sure you are watching them in HQ on YouTube to see more details and if you like these videos, make sure you rate them.
PerfSheet is a very handy solution based on Microsoft Excel scripting and let you automate extraction and charting of any data you can extract from an Oracle database (and generally speaking, any other database). The best thing is that Tanel has put great efforts in it and made it available to everyone for free. One demo is worth many words so here we go: Read the rest of this entry . . .
At the March Boston MySQL User Group meeting, Jacob Nikom of MIT’s Lincoln Laboratory presented “Optimizing Concurrent Storage and Retrieval Operations for Real-Time Surveillance Applications.” In the middle of the talk, Jacob said he sometimes calls what he did in this application as “real-time data warehousing”, which was so accurate I decided to give that title to this blog post.
Brian Aker delivers the keynote speech at OpenSQL Camp: State of the Open Source Databases. The presentation begins with a disclaimer: “There is no way I’m going to tell you exactly where the future of databases go. We have way too many egos in the room to ever even begin a discussion…”
and ends with Aker saying, “What the hell does that mean?”
Here’s a cool video of Alex Gorbachev commenting on the Ellison announcements today to Oracle corporate communications, just moments after the end of the keynote:
