Search

Top 60 Oracle Blogs

Recent comments

Uncategorized

Words fail me

I just stumbled across this fine example of the art of writing news articles when you clearly don’t understand the subject. The article has a date of 2 days ago on the front page, though curiously a September 2009 date on the article. The article purports to discuss the omotion feature of Oracle Rac One-Node. My [...]

Test to verify feed settings

Feed transfer did not apparently work.

VMWare Hires Redis Key Developer – But Why?

My friend MosheZ alerted me to the fact (which few hours later appeared all over the net) that VMWare hired Redis key developer. Which is as close to acquisition as you can get with an open source project.

What is Redis? Redis is yet-another-NoSQL. A key-value store, somewhat similar to Tokyo Cabinet. Except that Redis does persistence differently, which makes it faster in many cases. Redis started as a Memcached replacement, so a lot of the documentation describes it as follows: Redis is like Memcached, except it supports more data types, it is persistent to some degree and it is not distributed.

But the more interesting question is – Why does VMWare need Redis?

VMWare says: “As VMware continues its investments in the context of cloud computing, technologies such as Redis become key for future cloud based apps, whether private or public cloud, and the cloud infrastructure itself.”

So Redis is cloud and VMWare is a major cloud player, therefore VMWare needs redis. Two discrepancies stand out in this story:

Always Check Your Backups

So this is a 2 node RAC cluster on RHEL that was recently upgraded from 10.2.0.2 to 10.2.0.4. Since then clusterware restarts crs every few hours (8 in fact). A little research suggests that this can indicate problems with the automated OCR backup.  The first thing therefore is to check the state of the backups. [server] [...]

Back Again

So if all goes well the blog should be back again, now powered by WordPress. The blogger posts have made it back, but apparently 2006-2008 never existed. Fortunately it’s probably only me that cares. Those who know me personally will know that I moved jobs, and therefore needed to understand what the “private blogging” position [...]

How to CANCEL a query running in another session?

Here’s a treat for Oracle geeks, hackers and maniacs out there…

Update: As the beginning says, this article was meant as something interesting about Oracle’s internals and CTRL+C / OCICancel() handling. There’s a more practical way for canceling session calls if you are running Oracle Enterprise Edition and are currently using resource manager:

You can set the consumer group for a session to CANCEL_SQL to cancel its current call:

DBMS_RESOURCE_MANAGER.SWITCH_CONSUMER_GROUP_FOR_SESS (
session_id IN NUMBER,
session_serial IN NUMBER,
consumer_group IN VARCHAR2);

Thanks to commenter “null” for this info. Note that I haven’t tested how/whether this feature works correctly so there’s homework for you ;-)

I recently received a question about how to cancel queries running in another Oracle session, so that the session would not be killed, but would remain alive.

Well, there’s no supported way I can tell you, but thanks to how Oracle handles out-of-band breaks on Unix platforms, you can cancel database calls using an OS tool – kill.

Before we go on, here’s how query cancellation (pressing CTRL+C in sqlplus for example) works in Oracle:

Using Process Memory Matrix script for calculating Oracle process memory usage on Solaris

I just published a new script and article about calculating the real Oracle process memory usage on Solaris.

The problem with V$PROCESS* views (and the V$SESSTAT) is that they will tell you what Oracle thinks it’s using, not the real amount of memory used. There will be discrepancies due how memory is actually allocated in OS, libraries out of Oracle’s control, the static memory areas inside Oracle binary and of course bugs.

I was working on one of such problems and decided to make my life easier by writing the script. It’s not so much about calculating the exact figures (they will never be 100% correct), but more about presenting the memory usage data in a better and more convenient fashion.

The script is called procmm and stands for Process Memory Matrix as it shows the memory usage in a matrix grid.

Here’s an example output to show what I’m talking about:

Data Access APIs–Part 1: Fun with UPI

First, I’d like to apologize to our good friend SQLLIB.  Those of you who have been working with the Oracle Database for some time will notice that, while it too is a common data access library, I’ve omitted it from this series of posts. No, it’s not because of some personal vendetta against SQLLIB.  In […]

Upcoming Presentation Slots, Spring 2010

I will be presenting the Oracle Wait Interface is Useless Dog and Pony show a couple of times this spring. It was first presented at the UKOUG 2009 with Tanel Poder, and will be seeing the light of day at the following events:

I hope to see some of you there, and will get the final part posted before RMOUG – so the picture will be complete. If you’ve got any questions, it’s a good opportunity to come and heckle at one of those events!

NEXTGRES Gateway: MySQL Emulator for Oracle

So, a few people have asked me what NEXTGRES Gateway is.  My short answer, the ultimate database compatibility server. Sorry if this blog entry sounds very marketing-oriented, but I’ve been working on this personal project non-stop for the last 8 months and am really excited about it. NEXTGRES Gateway in a nutshell: Designed to assist […]