Oracle Team

Oracle multitenant dictionary: rowcache

By Franck Pachot . I’ve not finished with my investigation on 12c multitenant dictionary. Here, I’m checking how metadata links are managed by the dictionary cache (aka rowcache). As I did previously, I’ll create a metadata link function(…)

IOUG Collaborate #C15LV

By Franck Pachot . The IOUG – Independant Oracle User Group – has a great event each year: the COLLABORATE. This year it’s in April 12-16, 2015 at The Mandalay Bay Resort & Casino in Las Vegas. I’ll be(…)

Flush one SQL statement to hard parse it again

By Franck Pachot . If you want a statement to be hard parsed on its next execution, you can flush the shared pool, but you don’t want all the cursors to be hard parsed. Here is how to flush(…)

Stay with non-CDB or go to CDB?

By Franck Pachot . This is a question that starts to be raised quite frequently. Oracle released the multitenant architecture 1.5 year ago. And now says that the previous architecture – known as non-CDB – is deprecated. What does(…)

When to gather workload system statistics?

By Franck Pachot . This month we started to give our Oracle Tuning Workshop. And with a new workshop comes new questions. We advise to give to the optimizer the most accurate statsistics that we can have. That(…)

Oracle OPatch and “Archive not applied” error

Recently, I have installed an Oracle 11.2.0.4 RDBMS on a server, and I wanted to install the latest Patch Set Update (PSU) 11.2.0.4.4 from October 2014. During the execution, I fell on the error “Archive not applied” and the job(…)

NLS_LANG on Windows in Europe: WE8MSWIN1252 or WE8PC850?

By Franck Pachot . In europe we have accents and non US7ASCII characters. We need special characterset. I’m not talking about Unicode here that solves all the problems. If you have a Java application, you have no problem: it’s(…)

Flashback logging overhead: ‘db file sequential read’ on UNDO tablespace

By Franck Pachot . in my previous post I’ve reproduced an issue where some bulk insert into a GTT was generating too much undo. But the real case I encountered was worse: the insert was reading lot of(…)

Insert into GTT: bulk with APPEND_VALUES

By Franck Pachot . This post is about the case I had where a GTT was generating too much undo. The effects were amplified by the fact that the database was in flashback logging (see Jonathan Lewis answer in(…)

Oracle multitenant dictionary: upgrade

By Franck Pachot . This is a second part of the previous post about metadata link. I’ve shown how a sharing=metadata function becomes a sharing=none function when it is changed in the pdb – i.e when not having(…)