Something I presented recently during an Oracle Database 12c Performance Management and Tuning class. Hints are a double-edged sword; they may do more harm than good. What if hinted SQL comes from an application that you as the DBA in charge can’t modify? You can tell the Optimizer to ignore that nasty hint.
One method is to use alter session set “_optimizer_ignore_hints”=true; This will make the optimizer ignore all hints during that session – also the useful ones, so maybe that is not desirable. The method I show here works on the statement level. The playground:
The Data Guard Broker is recommended for various reasons, this one is less obvious: It prevents a Split-Brain problem that may otherwise occur in certain situations. Let me show you:
Join us with this FREE event on May 19, 13:00 CET and register now, because seats are limited.
I will be talking about
These topics will be live demonstrated – positively no slide show reading.
If you speak often at conferences, sharing your screen to demo things, this could be helpful:
Throughout your presentation, the audience will be able to see your Twitter Handle, reminding them to include it with tweets about the event. I used to include it in the slides, but this is better, because it works also with live demonstrations where no slides are being showed. Which is incidentally my favorite way to do presentations
Straight after the Oracle University Expert Summit in Berlin – which was a big success, by the way – the circus moved on to another amazing place: Istanbul!
The Turkish Oracle User Group (TROUG) did its annual conference in the rooms of the Istanbul Technical University with local and international speakers and a quite attracting agenda.
Do you recognize anyone here?
Today, I got this message in my alert.log file:
Full DB Caching disabled: DEFAULT_CACHE_SIZE should be at least 709 MBs bigger than current size.
When I look at the datafile sizes and compare them with the buffer cache size, it shows:
Join us in Berlin, 18th – 20th April. The event will take place at the Adlon Hotel with Jonathan Lewis, Pete Finnigan, Christian Antognini, Javier de la Torre Medina and myself as speakers. We have over 70 enrollments already, so take action to secure your seat in time!
On behalf of Oracle University, I will be delivering a free webinar, Tuesday 26th January 2016:
http://www.oracle.com/uk/education/eblast/uk-dba-advanced-admin-181215-ol-2835011.html
Expect live demonstrations as the major content – I promise to keep the marketing part to a minimum :-)
Another year has passed. I take the opportunity to thank you for visiting and to wish you a Happy New Year 2016!
In case you didn’t recognize: That is supposed to look like fireworks, The Oracle Instructor style ;-)
2015 was a great year for uhesse.com with 345,000+ views and the crossing of the one million hits threshold. Top countries with more than 4,000 views in 2015 were
This is how an upgrade with pluggable databases looks conceptually:
You have two multitenant databases from different versions in place. Preferably they share the same storage, which allows to do the upgrade without having to move any datafiles
You unplug the pluggable database from the first multitenant database, then you drop it. That is a fast logical operation that does not delete any files
Next step is to plug in the pluggable database into the multitenant database from the higher version
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