Ardent Performance Computing
Technical
10g Subquery Unnesting Anomalies
I’ve been spending quite a bit of time over the past week studying subquery optimization. It started with an anomaly I noticed at a client site and led me through a refresher on Jonathan Lewis’ chapter on transformations and through a lot of time reading trace files. I’ll probably write a few posts about subqueries… … Continue reading
NFS and Stats Collection in Oracle 11g
A few more 11g new features – that you might not have heard about yet – which stand out in my opinion! Direct NFS First, Kevin just posted whitepaper/press release links and made some comments about Direct NFS. Oracle 10g introduced ASM – streamlining hardware access by effectively allowing the database engine to bypass all … Continue reading
Compression in 11g: Time To Pay Attention
Well 11g is officially “launched”. I think that just means you can download the white papers from OTN now. Seems that the actual software itself still isn’t available although there was talk that it would be released by August or something – on Linux at least. I’m not exactly holding my breath although I do … Continue reading
Case Study: Statspack/AWR Latch Waits (Part 2)
What a day! Yesterday I spent about seven hours downtown taking two exams: the RAC beta exam in the morning and the Oracle on Linux beta exam in the afternoon. The Linux exam was pretty easy for me but the RAC one had a lot of questions that made me think… and there wasn’t much … Continue reading
Case Study: Statspack/AWR Latch Waits (Part 1)
I thought it might be interesting to write about a situation I ran into last week and a bit of the methodology I used to tackle it. The whole thing started as a health check for a PeopleSoft database. To give a little background, the whole environment lives on a 32-processor IBM p690 partitioned into … Continue reading
Monitoring Oracle on SMP with Hyper-Threading
So I’ve really been digging Kevin Closson’s blog lately. Back at the beginning of this month he had another post that caught my attention about running Oracle on Opteron in which he made the point that these boxes should always be run in NUMA mode (not SUMA). This grabbed my eye because I’ve been delving … Continue reading
Monitoring Oracle on NFS
Wow – the last three weeks have been crazy! During the last week of May I was wrapping up the services paper and a few submissions for the UKOUG. And for the first two weeks of June I’ve been working on some performance problems for one of our clients in the Phoenix area. Nice weather … Continue reading
Accessing Arbitrary Ancestors in Hierarchical Queries
Last Friday I wrote about a client query that could be rewritten in a much more optimized manner. However rewriting it was a little tricky, involving a hierarchical query and a column that needed to calculate a value based on it’s parent, grand-parent, great-grand-parent, etc. Raj posted a very smart solution that used sys_connect_by_path to … Continue reading
Encyclopedia Spine Problem
Dominic just posted a hint to the encyclopedia spine problem he posted last week. Sheesh… personally I think the hint totally gave it away. Or at least it gave away one solution. Here’s what I came up with. I wonder if this is how Dominic solved the problem:
Combining Hierarchical Queries With Analytics
Just a few days ago I was reading Dominic’s challenge to write a query that would give results like an Encyclopedia Spline. It apparently took over the entire day for another Dominic and I was planning to take it on myself too as soon as I had the time… but today another challenge came my … Continue reading
Disclaimer
This is my personal website. The views expressed here are mine alone and may not reflect the views of my employer.
contact: schneider @ ardentperf.com
Ardent Performance Computing 
Recent Comments