In my last post, I described a quick show case for Oracle 12c Automatic Big Table Caching. But ABTC is just a crock, nevertheless a useful one. The biggest help from Automatic Big Table Caching for “sustainable” database performance management is the temperature of segments, heated up by TABLE ACCESS FULL. In my case, after enabling ABTC […]
Year: 2016
Oracle Automatic Big Table Caching – an improvement, not a fix
Too much TABLE ACCESS FULL in your Oracle Database? Thus, SQL elapsed time too slow for the demand? Plenty of Buffer Cache to create a temporary fix? maybe you want to consider Automatic Big Table Caching. Usually, Oracle only does Full Table Caching for small tables. Big ones will only use the Buffer Cache for the current chunk […]
Oracle 11g unable to extend datafile but ASM disk group shows free space
Sometimes Oracle Database 11gR2 complains about not being able to extend a (lob) segment with ORA-1691, but ASM monitoring based on USABLE_FILE_MB did not fire. Adding a new data file fails with ASM ORA-15041. I was under the impression this behaviour of ASM deserved some explanation. Situation Database Alert Log complains with ORA-1691: ORA-1691: unable to extend lobsegment MYUSER.SYS_LOB0013128030C00003$$ […]
My COLLABORATE16 look-at’s – an aftermath
From April 10th to April 14th 2016 many Oracle professionals congregated in Las Vegas. The three big U.S. user groups, the IOUG, the OAUG and the Quest User Group once again formed one of the best Oracle Conferences in the world: COLLABORATE16. I was honored to be there as a speaker, and glad to perform […]
Oracle SQL showing current expensive queries plus most expensive object from execution plan
Sometimes, it’s useful to see what’s currently going on in your Oracle Database. This query is meant to help with this task, that haunts every DBA from time to time. It’s just using v$sql and v$sql_plan, so no need for Enterprise Edition and Diagnostics Pack. Key features: find top buffer getters per execution from v$sql […]
Looking forward to speaking at COLLABORATE16 IOUG Forum
Yes, I did it again, submitted and got two papers accepted – speaking at COLLABORATE16 in Las Vegas (#C16LV) is always a highlight of the year! This time, it will be: The Bad One In Your Crop – SQL Tuning Analysis For DBAs 4:30 PM–5:30 PM Apr 11, 2016, Palm-A Oracle Core: 12c InMemory Column […]
Featured by Oracle Magazine
The Oracle Magazine featured me in its January / February 2016 issue. I really feel honoured and would like to say thank you for the opportunity! For details, please see the Performing Databases Blog post about the publication. […]
DOAG noon2noon RAC & Dataguard – Quick Report
There’s always something to learn – for example about Oracle RAC (Real Application Clusters) and Dataguard. And the old-school frontal teaching concept is boring, and more important, ineffective after a few hours of passive listening. So the German Oracle Users Group DOAG organized a “noon2noon” event: “Oracle RAC and Dataguard” this week in Würzburg (January 2 1st-22nd 2016). It was the […]
How to disable Oracle ACFS drivers / registry resource
Sometimes an installed ACFS can cause trouble, especially if we don’t or can’t use it (e.g. when not using an UEK Linux kernel, like with SuSE Linux Enterprise Server SLES). There’s lots of documentation how to create and maintain ACFS file systems, but how to get rid of ACFS at all wasn’t so easy to […]