My today morning’s Advanced Oracle Troubleshooting presentation was quite a success. The 400 people room was fully pre-booked and over 300 people showed up. This is a pretty good result considering that a) my presentation was an 9 am one on the last day of conference and b) there was a big party last night :)

Thanks to everyone who attended!

I have uploaded the slides here: http://www.tanelpoder.com/files/Advanced_Oracle_Troubleshooting.pdf

PerfSheet (the Excel based automatic data visualization tool) is uploaded here: http://www.tanelpoder.com/files/PerfSheet.zip

The TPT scripts (scripts like snapper, latchprofx, ostackprof etc I demoed and a lot more) are uploaded here: http://www.tanelpoder.com/files/TPT_public.zip

Few links to my past blog entries about how to use Snapper, LatchProfX and os_explain:

• Advanced Oracle Troubleshooting Guide, part 8: LatchProfX
• Oracle Session Snapper v1.06 released
• Advanced Oracle Troubleshooting Guide, part 6: os_explain

I haven’t blogged about usage of OStackProf yet (as the tool’s very fresh), I will do so in coming week.

Feel free to send any further questions to tanel@tanelpoder.com

Also, if you liked my presentation, you will sure like my 2-day seminar on the same topic. I will go even deeper in there ;-)

Check out this page: http://blog.tanelpoder.com/seminar/. I’ve arranged my seminar in 18 cities already for 2008 and early 2009, if your city is not in the list, let me know and I’ll see what I can do :)

Thanks once more for everyone attending my OOW presentation and also my blog readers for continued support!

Tanel Poder Cool stuff, Internals, Oracle, Oracle 11g, Performance, Troubleshooting

I’ve been too busy lately to write anything serious here (and still am).

I noticed that that Oracle 11g patchset 11.1.0.7 for Linux 32/64bit is available, so that’s what I’ll be dealing with during my 20 hour flight from Singapore to San Francisco tomorrow :)

See you at Oracle OpenWorld and thanks for all the people who signed up for my troubleshooting session. The room I was supposed to speak in got fully booked, my session got moved to a larger room which is now full as well. So see you on Thursday 9am in Moscone South room 306 (unless it’s changed again…)

Tanel Poder Oracle, Oracle 11g

If you’re interested in leading edge database research, the VLDB 2008 proceedings are publicly available now.

Multiple Oracle-specific presentations are available on the industry track page

Here are direct links to them:

• Oracle SecureFiles System
• Optimizer Plan Change Management: Improved Stability and Performance in Oracle 11g
• Closing The Query Processing Loop in Oracle 11g (this one is about adaptive cursor sharing)

Enjoy! :)

Tanel Poder Design, Internals, Oracle, Oracle 11g

I have written two posts in one, about a performance issue with writes in system tablespace and introduction of a little DTrace stack sampling script.

Have you noticed that DML on tables residing in SYSTEM tablespace is slower than tables in other tablespaces?

Here’s an example, I’ll create two similar tables, one in USERS tablespace, other in SYSTEM, and inset into the first one (Oracle 10.2.0.3 on Solaris x64):

SQL> create table t1(a int) tablespace USERS;

Table created.

SQL> create table t2(a int) tablespace SYSTEM;

Table created.

SQL> exec for i in 1..100000 loop insert into t1 values(i); end loop;

PL/SQL procedure successfully completed.

Elapsed: 00:00:03.09

Insert into table in USERS tablespace took 3 seconds.

Ok, let’s commit and flush dirty buffers that they wouldn’t get on the way of next insert.

SQL> commit;

Commit complete.

Elapsed: 00:00:00.02

SQL> alter system checkpoint; -- checkpointing to flush dirty buffers from previous inserts

System altered.

Elapsed: 00:00:01.34
SQL>

And now to the insert into the SYSTEM tablespace table:

SQL> exec for i in 1..100000 loop insert into t2 values(i); end loop;

PL/SQL procedure successfully completed.

Elapsed: 00:00:08.98
SQL>

What?! The same insert took 3 times longer, almost 9 seconds?

Fine! Let’s troubleshoot it!

Read more…

Tanel Poder Administration, DTrace, Internals, Oracle, Performance, Tools