performance

I’ll be co-speaking with Randy Johnson (one of the authors of Expert Oracle Exadata) at E4 to share about the war stories and detail on a bunch of technical stuff on a Peoplesoft and BIEE consolidation project we had on one of our clients. See the abstract below:

Last week I had a lengthy post at oracle-l that tackles Calibrate IO, Short Stroking, Stripe size, UEK kernel, and ASM redundancy effect on IOPS Exadata which you can read here
followed by interesting exchange of tweets with Kevin Closson here (see 06/21-22 tweets) which I was replying in between games at UnderwaterHockey US Nationals 2012 which we won the championship for the B division I have my awesome photo with the medal here

June 28, 2012 (Modified June 28, 2012) Sometimes it is possible to build a very effective test case to reproduce a particular problem.  Sometimes the test case drifts a bit offtrack, in the process revealing other information that is not directly related to the original problem that the test case attempted to simulate.  You will [...]

A short update on the how, what and where. I got really annoyed with the website performance, so hereby a different look and feel that hopefully (trimmed and all) will provide a faster load time of pages and other material. I also introduced some caching mechanisms that hopefully will be helpful. A faster reference to

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I started writing this post in early January this year and before it gets completely old and (maybe) uninteresting, I hereby just post it, wondering what you might think. Of course I wanted to be it the ultimate perfect braindump but I realize that I can’t get my head around all the issues anyway and

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June 20, 2012 I have not had much time to respond in OTN threads recently, although I do still occasionally read threads on the forum.  I was a little surprised by one of the late responses in one of the recent threads, where one of the responders suggested actually testing the problem with the assistance of [...]

I have a permanent job at the NetCracker‘s System Performance group. Recently I was offered to do one day job outside, on-site in another company, which coincidentally has an office close to NetCracker’s Moscow office. It was an opportunity to apply my skills in a completely different situation which I couldn’t miss; plus I’ve never done public presentations before and this was a good occasion to practice that. Here I’d like to write down some notes how the event went.

One of the biggest problems in software performance today occurs when the people who write software are different from the people who are required to solve the performance problems that their software causes. It works like this:

1. Architects design a system and pass the specification off to the developers.
2. The developers implement the specs the architects gave them, while the architects move on to design another system.
3. When the developers are “done” with their phase, they pass the code off to the production operations team. The operators run the system the developers gave them, while the developers move on to write another system.

The process is an assembly line for software: architects specialize in architecture, developers specialize in development, and operators specialize in operating. It sounds like the principle of industrial efficiency taken to its logical conclusion in the software world.

You might have expected the following query ought to run reasonably efficiently, after all it seems to be targeted very accurately at precisely the few rows of information I’m interested in:

select
	column_name,
	avg_col_len
from
	dba_subpart_col_statistics
where
	owner             = 'TEST_USER'
and 	table_name        = 'TEST_COMP'
and	subpartition_name = 'P_MAX_D'

I’m after some subpartition column stats (so that I can work out whether a subpartition of a local index on a composite partition is roughly the right size) and I’m querying the view by the only columns that seem to be there to allow me to access the data efficiently. Unfortunately the execution plan isn’t doing what I need it to do. The following plan is coming from a small 11.2.0.3 database with up to date statistics:

May 30, 2012 A question appeared on the OTN Database forums yesterday that has yet to receive an answer.  The question was essentially, why did the execution plan change when the OPTIMIZER_FEATURES_ENABLED parameter was adjusted from 11.2.0.2 to 11.1.0.7, and why did the execution performance improve as a result of making the change?  A DBMS_XPLAN [...]