Search

Top 60 Oracle Blogs

Recent comments

March 2014

  • warning: SimpleXMLElement::__construct(): Entity: line 1: parser error : Space required after the Public Identifier in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): ^ in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): Entity: line 1: parser error : SystemLiteral " or ' expected in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): ^ in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): Entity: line 1: parser error : SYSTEM or PUBLIC, the URI is missing in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.
  • warning: SimpleXMLElement::__construct(): ^ in /www/oaktable/sites/all/modules/amazon/amazon.module on line 262.

IOUG Collaborate 2014 and EM12c Odyssey

Collaborate is coming up fast and this year is going to be a great conference for all involved.  I’ll have a number of sessions, both for those attending in person and those taking advantage of the virtual content.

RLS bug

RLS – row level security, aka VPD (virtual private database) or FGAC (fine grained access control) has a critical bug in 11g. The bug is unpublished, but gets mentioned in various other documents, so can be identified as: Bug: 7828323 “SYS_CONTEXTS RETURNS WRONG VALUE WITH SHARED_CONTEXT_SENSITIVE”

The title tells you nearly everything you need to know – if you’ve declared a security policy as context_sensitive or shared_context_sensitive then a change to the context ought to result in the associated predicate function being called to generate a new security predicate the next time the policy becomes relevant. Thanks to bug 7828323 this doesn’t always happen – so queries can return the wrong set of results.

RLS bug

RLS – row level security, aka VPD (virtual private database) or FGAC (fine grained access control) has a critical bug in 11g. The bug is unpublished, but gets mentioned in various other documents, so can be identified as: Bug: 7828323 “SYS_CONTEXTS RETURNS WRONG VALUE WITH SHARED_CONTEXT_SENSITIVE”

The title tells you nearly everything you need to know – if you’ve declared a security policy as context_sensitive or shared_context_sensitive then a change to the context ought to result in the associated predicate function being called to generate a new security predicate the next time the policy becomes relevant. Thanks to bug 7828323 this doesn’t always happen – so queries can return the wrong set of results.

Automated Linux VM build on ESX

How to automatically install RedHat like (Red Hat, Cent OS, Oracle Enterprise Linux) Linux system on ESX or VirtualBox servers ? There are at least two methods. I have seen VM cloning in lot of places using ESX (VSphere Center) or VirtualBox functionality. Cloning is fine but it required some intervention after clone will be finished (like host rename or IP address change). What if we want to install different releases of systems - well it is required to have a clone of every single release like RedHat 6.2, OEL 6.3 or OEL 6.4. It require a rework every time a new release is available on the market.

Automated Linux VM build on ESX

How to automatically install RedHat like (Red Hat, Cent OS, Oracle Enterprise Linux) Linux system on ESX or VirtualBox servers ? There are at least two methods. I have seen VM cloning in lot of places using ESX (VSphere Center) or VirtualBox functionality. Cloning is fine but it required some intervention after clone will be finished (like host rename or IP address change). What if we want to install different releases of systems - well it is required to have a clone of every single release like RedHat 6.2, OEL 6.3 or OEL 6.4. It require a rework every time a new release is available on the market.

Practical Oracle Database Appliance

Book: 

Effective Indexing Webinar

Thanks to everyone for attending today's Effective Indexing webinar sponsored by IOUG with Embarcadero. For attendees, IOUG will likely send out a link to the recording and PDF of the presentation, but I also wanted to post it here.

Presentation PDF
Webinar recording

Analysing Parallel Execution Skew - Video Tutorial

Along the new mini series "Parallel Execution Skew" at "AllThingsOracle.com" that provides some information what you can do if you happen to have a parallel SQL execution that is affected by work distribution problems I'm publishing a series of video tutorials that explain how you can actually detect and measure whether a SQL execution is affected by skew or not.

Originally this tutorial was planned as one part (Part 5 actually) of the XPLAN_ASH video tutorial series, however so far I've only managed to publish just the inital two parts of that series, and these are already a bit outdated as I've released new versions of the XPLAN_ASH tool with significant changes and enhancements since then.