Thursday, September 29, 2011

Oracle openworld 2011

Oracle openworld 2011 is almost here . Starting Sunday I will be very active in tweeting as @fuadar an blogging via this blog . This is an exciting year to be at openworld and hopefully there will much to report see and publish

Sunday, September 25, 2011

Compatibility parameter and testing

As with any upgrade it is very important to have as proper test plan to test your application prior to a database upgrade. DBA's try to work with their application teams to ensure that the test are fair and balanced and go thru many weeks of planning before actually upgrading a major system.
One thing many DBA's do  as  a precautionary measure is to ensure that a backout plan is in place. For most it might includes backup, flashback or both. Once other medium of protecting your self is the compatibility parameters. After an upgrade the compatibility parameter is most often not changed till the application is stable. The compatibility parameter to a lower value allows for  potentially downgrading your database.
But what if your application testing was done with the compatibility parameter not set to the right version. This can cause a lot of headaches for the DBA's and the Application teams that are testing/
Compatibility parameters not only change the redo logs and the control file structure but also allow for oracle to take new code paths. Something that was very painfully evident to us when we migrated from 10.2.0.4 to 11.2.0.2 RAC. The compatibility changed actually caused us a lot of instability due to some new processes that oracle introduced. This  change caused us to go from a fully stable system to crashing down every couple of hours.
Unfortunately there is no easy remedy for changing the compatible parameter and we had to work thru the issues. A lesson well learned for us. Testing needs to be done with compatibility changes done  on dev and test to ensure process behaviour does not change

GTX Processes in Oracle 11.2.X

Oracle Has introduced new processes in Oracle 11 and above to handle XA type processes.
The Parameter global_txn_processes control is you want GTX processes to spawn or not.
If global_txn_processes >0  oracle will autotune in 11.2.0 the amount of gtx processes it needs per node.
these processes are normally used for distributed transactions and for XA based transactions. if you are using the OracleXA dataclass in your jdbc driver. you are probably using DTP or distributed transaction processing.

RAC Attack at Oracle Openworld

This year among many things the OTM Lounge will be host to IOUG RAC Attack
Jeremy  has information on this wonderful event at this blog.  Also if you have experience in RAC installation . please hit up  the Rac Attack  webpage for more info.
Hope to see everyone there.

Wednesday, September 14, 2011

The Arrival of #OOW11 and Festivties galore

Its that time of the year. Oracle OpenWorld 2011  starts in a few weeks.
Oracle Openworld  is host to an insanely massive amount of DBA's architects , developers and vendors. It is a massive Opportunity  not only to learn from peers but network with experts, Oracle ACE's and ACE directors.
While i will be posting the sessions i will be attending in a separate post i just thought I'd point out to some of the festivities  Like the Bloggers Meetup that is probably the best place to meet the greatest minds that have a real job working on Oracle related Technologies . The Details are on the Pythian Blog   and can be read in detail on pythian's blog . An excerpt from the pythian blog is below
"What: Oracle Bloggers Meetup 2011
When: Wed, 5-Oct-2011, 5:00pm


The Other Festivities include the OTN night Details on the OTN Blog. But one thing is good OTN Lounge is going to be in Howard Street which is awesome again. 
One Cool Thing on the OTN Lounge will be RAC SIG stuff

"(Special treat for Oracle RAC fans: Kick back at the OTN Lounge between 9am and 1pm each day of the show with experts from the IOUG RAC SIG, and work together to get an Oracle RAC cluster database running inside virtual machines on your own laptops.)" --From OTN Blog

I' am also hoping Oracle Closed World returns since i was unable to attend any #ocw sessions last year. Thati s a festive geek fest in itself.

Come Join us at Oracle Openworld for lots of fun and learning. and do introduce yourself.
i'm @fuadar on twitter  and #OOW11 is the official tag of Oracle OpenWorld 2011

 






Thursday, September 01, 2011

AIX Bug with 64K Memory Pages

After our Production Upgrade to 11.2.0.2 on AIX. we hit an AIX Bug relating to  AIX starving Oracle from memory pages and thus grinding the system to a halt.. Metalink Doc  1088074.1 talk about this but there was conflicting information thru Doc ID 282036.1 which stops at AIX 6.1 TL5 for this particular bug.
It is the Bug is actually fixed in TL6 SP4 .
We were on TL6 SP2 and thus had a system outage.
Moral of the story is it always pays to ensure to look at future TL's and SP's for AIX to ensure the bug was actually fixed.

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