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Database Feed

Oracle Database, Oracle 10g, Oracle 11g, Oracle XE, Oracle RAC, Oracle Instant Client, Oracle Data Guard and Oracle Exadata resources, news, and support articles.

Followup on the 4k DML bug

Another piece of good news — Oracle has opened a bug for yet another anomaly I reported earlier in my blog: row-by-row processing of bulk DML when the block size on the target table is less than the default 8k. So it’s now officially bug 20039770 – “DML SLOW WITH 4K BLOCK SIZE VS 8K BLOCK SIZE”.

Oracle locks: Identifiying blocking sessions

When you have sessions blocked on locks, you probably have all information about the waiters (they call you and anyway their waiting session is visible in v$session our ASH). But you usually need to get enough information that help to identify the blocker. Here is a query I use to get that quickly, based on V$WAIT_CHAINS
Here is the result I want to get:

After Trigger to save data on based on uncommitted update

Env: Oracle ADF, Oracle 11g

Situation: Have ADF transaction processing 2 tables (a, b) data logic and committing them in same transaction.

ADF Application Transaction T1 starts
Table A, record A1 updated
Table B, new record B1 inserted --> After insert Autonomous database Trigger T1 fires
Trigger T1 logic: Based on A1 updated value, insert new Record B2 record in Table B and explicitly commit in trigger logic.
Transaction completes (commit)

Think Stats, 2nd Edition Exploratory Data Analysis By Allen B. Downey; O'Reilly Media

Lots of Python with data analysis books. This might be a good one that is able to help readers perform statistical analysis with programs written in Python.

Plan puzzle

I was in Munich a few weeks ago running a course on Designing Optimal SQL and Troubleshooting and Tuning, but just before I flew in to Munich one of the attendees emailed me with an example of a statement that behaved a little strangely and asked me if we could look at it during the course.  It displays an odd little feature, and I thought it might be interesting to write up what I did to find out what was going on. We’ll start with the problem query and execution plan: on AIX

just released today

only in Enterprise Edition at the moment, and now available on HPUX, zLinux and AIX

My planning for DOAG 2014

I'm quickly checking the planning for DOAG these 3 days and here is the list of sessions I would like to attend.
There are still a lot of interesting ones even if my choice is limited by the language (I would like to understand German but I'm limited so sessions in English). And I've still some concurrency issues to solve because I cannot be at two places at the same time.

12c SQL Plan Directive: state has changed between and

SQL plan Directives have been introduced in 12c. If you have scripts that check their states (and I have that as I prefer to monitor closely the features that are new) you probably have seen a difference when going from - the first release of 12c and the only one avilable yet in Standard Edition - and - the first patchest. I'll explain here what are the SQL Plan Directive states and how they changed.

Thoth Gateway 1.4.0 beta release 1 available

As mentioned in my previous post about the Thoth Gateway, a mod_plsql and Apex Listener alternative that runs on IIS, the goal for the next release of the gateway (tentatively called version 1.4.0) is to change the Oracle Data Provider for .NET (ODP.NET) from the "Unmanaged" to the "Managed" driver.

APEX and Privileges Granted through Roles

The mystery has finally been solved. England’s surrendering of the Ashes last winter was nothing to do with Australia being a much better cricket team. Thanks to Kevin Pietersen’s recently published Autobiography, we now know that the problem was that there were rather too many silly points in the England dressing room.
Moving swiftly on from that weak pun, the subject at hand can also be rather mystifying at first glance.

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