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May 2016

Oracle SGA memory allocation on startup

Recently I have been presenting on what running on a large intel based NUMA system looks like (OTN EMEA tour in Düsseldorf and Milan, and I will be presenting about this at the Dutch AMIS 25th anniversary event in june). The investigation of this presentation is done on a SGI UV 300 machine with 24 terabyte of memory, 32 sockets (=NUMA nodes), 480 core’s and 960 threads.

Recently I have been given access to a new version of the UV 300, the UV 300 RL, for which the CPU has improved from Ivy Bridge to Haswell, and now has 18 core’s per socket instead of 15, which means the number of core’s on a fully equipped system is 576, which makes 1152 threads.

Friday Philosophy – Half Million Views

I only noticed yesterday that I’ve had just over half a million views on my blog since I started it back in 2009.

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I think that is direct views on the blog and does not include the odd syndicated place such as the Oaktable website. Though in my case, I don’t think syndicated views make much difference</p />
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Let me START WITH sequences

It’s always cool that you can learn stuff every single day, even on the most simple of topics.  This one came from an AskTom question.  We define a sequence to start with 100, and then alter it to modify the INCREMENT BY.

Options For Pre-EM13c Target Software and Non-Supported OS in EM13c

Per Oracle documentation, you’re able to upgrade from EM12c to EM13c, including the OMR, (Oracle Management Repository) to DB12c and the OMS, (Oracle Management Service) to EM13c, but leave the agent software at a version of 12.1.0.3 or highe

BI Publisher will not start (using emctl oms start and emctl oms start -bip_only)

*Customer names obfuscated to protect the innocent (and the guilty!)

This post covers a particular customer’s recovery scenario. They had reverted their config.xml to a previous version due to a failed attempt to integrate LDAP into WLS myrealm, and ever since, they have been unable to start BI Publisher via the emctl command. Although they can start it from the WLS Admin Console, the ’emctl status oms -details’ shows BI Publisher Server is Down, and they can’t even connect to it via the https://em12c.example.com:9702/xmlpserver/. They then attempted to run the emcli setup_bipublisher to re-register it with EM but get:

Amis Conference June 2nd and 3rd

I will be at the Amis conference next Friday in Leiden not far from Amsterdam in Holland. The conference is held over two days, June 2nd and 3rd But I will be there just on the Friday due to other....[Read More]

Posted by Pete On 26/05/16 At 11:28 AM

Storing Date Values As Characters (What’s Really Happening)

For something that’s generally considered an extremely bad idea, I’ve lost count of the number of times I’ve come across applications that insist on storing date values as characters within the database. We’ve all seen them … I recently got called in to assist a customer who was having issues with a POC in relation […]

CBO++

While browsing the web recently for articles on the HyperLogLog algorithm that Oracle uses for some of its approximate functions, I came upon a blog post written in Jan 2014 with the title Use Subqueries to Count Distinct 50X Faster. There are various ways that subqueries can be used to rewrite queries for improved performance, but when the title caught my eye I couldn’t think of a way in which they could improve “count distinct”.  It turned out that the word “subquery” was being used (quite correctly) in the sense of “inline view” while my mind had immediately turned to subqueries in the select list or where clause.

Are Zero Days or Bugs Fixed by CPU The Worst?

I spoke yesterday about compartmentalising Oracle Security and one element that comes out of this is the need to consider what you are trying to achieve; secure actual data and also secure the platform. In general applying security patches will....[Read More]

Posted by Pete On 25/05/16 At 12:51 PM

Tech 16 – We Want Your Abstracts on SE, Real-World & Practical Topics

The Call for Papers is open for the UK Oracle User Group annual TECH conference. It’s in Birmingham, in December, and is being co-located with the JDE & Apps conferences too (and the call for papers is open for them also).

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If you are a Standard Edition (SE) expert, have a real-world story to tell about how you used Oracle (good or bad!) or want to teach others how to get going with some aspect of Oracle, I really want to see your abstracts.