Jeff McQuigg has posted two presentations that he gave at Openworld 2010 on his website here: http://greatobi.wordpress.com/2010/10/26/oow-presos/ They’re full of real content and well worth a read. There’s excellent levels of detail and plenty to think about if you’re involved in OBI or DW development projects.

Continuing in the beard-scratching theme of Unix related posts (previously - awk), here’s a way to graph out the I/O profile of your Oracle database via the Oracle metrics in gv$sysstat, and gnuplot. This is only the system I/O as observed by Oracle, so for belts & braces (or to placate a cynical sysadmin ;-)) you may want to cross-reference it with something like sar. First, a pretty picture of what you can get:

More of a unix thing than DW/BI this post, but I have a beard so am semi-qualified…. The requirement was to improve the performance of some ODI processing that as part of its work was taking one huge input file, and splitting it into chunks based on content in the file. To add some (minor) spice the file was fixed width with no deliminators, so the easy awk answers that I found on google weren’t applicable.

Last month I wrote about a problem that Informatica as part of OBIA was causing us, wherein an expired database account would bring Oracle down by virtue of multiple connections from Informatica. I raised an SR with Oracle (under OBIA support), who after some back-and-forth with Informatica, were told: This is not a bug. That the two error messages coming back from Oracle are handled differently is the result of a design decision and as such not a product fault.

Jeff Atwood of Coding Horror fame observed: This is sage advice (if a little crude :-)) to bear in mind when building reports for users.

As Twitter learnt yesterday, you should always sanitise user input. I was amused to see My Oracle Support doing so….recursively :) The apostrophe in “doesn’t” got escaped once, and then again, and then again, and then again, and then again ……

Here’s one in the series of stupid things I’ve done but which Google has thrown no answers, so I post it here to help out fellow idiots. Today’s episode involves our SCM tool, TortoiseSVN. I’d been happily using it for over a year, when suddenly I couldn’t commit any more. I could browse and checkout to my heart’s content, but when I tried to commit, boom: Commit failed (details follow): Authorization failed

This query, based on AWR snapshots on sys.wrh$_sysstat, includes in its metrics the I/O read throughput for a given snapshot duration. However it’s important to realise the huge limitation to this figure - it’s an average. It completely shoots you in the foot if you’re looking at capacity requirements. Consider this real-life example extracted from the above query: [sourcecode] Timestamp Total Read MBPS =========================================== 14-SEP-10 05.15.12.660 113.748 14-SEP-10 06.00.40.953 202.250 14-SEP-10 06.

I’m a geek. I like understanding things in their absolute entirety. It frustrates me to have to make presumptions or assumptions about something. I like to get down ’n dirty and find out what makes things tick. So that necessitates reading manuals. And unfortunately, Oracle don’t make that easy all the time. Some of the manuals are not very good, and others are difficult to find. Given the complexity of the OBIEE stack and proliferation of terminology and product names, sorting the wheat from the chaff can be a headache.

Introduction We’re in the process of implemention Resource Manager (RM) on our Oracle 11gR1 Data Warehouse. We’ve currently got one DW application live, but have several more imminent. We identified RM as a suitable way of - as the name would suggest - managing the resources on the server. In the first instance we’re looking at simply protecting CPU for, and from, future applications. At some point it would be interesting to use some of the more granular and precise functions to demote long-running queries, have nighttime/daytime plans, etc.