Franck's Oracle blog
Blog of Franck Pachot, Consultant at dbi services
I'm a Senior Consultant, and Oracle Technology Leader at dbi services (Switzerland).
Certified DBA (OCM 11g, OCP 12c, Performance Tuning Expert, Exadata Implementation) I cover all database areas: architecture, data modeling, database design, tuning, operation, and training.
My preferred area is troubleshooting oracle and performance tuning, especially when I acheive to enable an efficient collaboration between the developers and the
As an Oracle Ace, I participate in the Oracle Community in forums, blogs, articles and presentation. You can follow my activity on this blog: and my twitter account: @FranckPachot
I've written about 12c online statistics gathering in a UKOUG OracleScene article. My opinion is clear about it: you sill need to gather stale stats afterwards or you have mising, stale and inconsistent object statistics. This post is about cases where online statistics gathering does not occur (and are not documented) - which is another reason why we can't rely on it.
I'm using Oracle SQL Developer 4.1 Early Adopter for a while and I like it. That version comes with a command line (in beta) which goal is to be fully compatible with sqlplus but running in java, and having a lot more features.
Becuse it's connecting with thin java driver by default, it doesn't use NLS_LANG. It's java. It's unicode. So here is how to set the language and characterset with the java options.
In the previous post we have seen how the OracleText index tables are maintained when new document arrives: At sync the new documents are read up to the available memory and words are inserted in the $I table with their mapping information. Now we will see how removed documents are processed. We will not cover updates as their are just delete + insert.
I plan to write several posts about OracleText indexes, which is a feature that is not used enough in my opinion. It's available in all editions and can index small text or large documents to search by words. When you create an OracleText index, a few tables are created to store the words and the association between those words and the table row that contains the document. I'll start to show how document inserts are processed.
For Exadata, oracle has introduced an 'EXADATA' mode which sets a high transfer rate (with IOTFRSPEED as in NOWORKLOAD statistics) and set a MBRC (as in WORKLOAD statistics). Those values are set rather than gathered because all the SmartScan optimization done at storage cell level, which makes the multiblock reads less expensive, is difficult to measure from the database.
Here I will explain what I stated in a previous blog: direct-path reads are not counted as multiblock reads for the MBRC system statistic. And direct-path read should be the main i/o path in Exadata as you probably bought that machine to benefit from SmartScan.
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 a speaker and a RAC Attack Ninja as well.
|IOUG COLLABORATE provides all the real-world technical training you need – not sales pitches. The IOUG Forum presents hundreds of educational sessions on Oracle technology, led by the most informed and accomplished Oracle users and experts in the world, bringing more than 5,500 Oracle technology and applications professionals to one venue for Oracle education, customer exchange and networking.|
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 only one statement, illustrated with the case where it can be useful.
During the performance training, here is how I introduce Adaptive Cursor Sharing, here is how I show the bind variable peeking problem that is well known by everyone that was DBA at the times of 9iR2 upgrades.
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 it mean? Do we have to go to the CDB architecture even if we dont want to use/pay multi-tenant?