Archive for the 'Doug's Oracle Blog' Category


More Blogs 0

It’s good to see some more people joining in, particularly those I already know and admire.

First up is Mark Bobak, who I’ve met at several conferences and, as you can tell from his first few posts, is likely to have some interesting technical tales to tell.

OraPerf.com back online 0

I was just looking up a link to the original YAPP paper so that I could include it in the course notes and then noticed Anjo Kolk’s site is back online. I think it might be a little while before things are back to normal, though - sounds like there’s a bit of work to be done ….

ASH and the psychology of Hidden Parameters 0

Time for a quick break from the final push to complete the course slides. I’ve (probably foolishly) decided to apply the 10.2.0.4 patch to my test database.

As I was confirming the details of when Oracle starts to flush information from the ASH Buffer to the workload repository, I thought I’d check the value as it’s defined in a hidden parameter, _ash_eflush_trigger. The default is 66, which means that the flush begins whenever the circular buffer is 66% used, to stop it from wrapping around on itself, or filling up, whichever description you prefer.

Optimiser - Upgrading from 9i to 10g 0

On the one hand, I regret the fact I seem to be posting a lot of links to other people’s work at the moment but I couldn’t let this one by, if only for those who don’t use OraNA or the like and might miss it.

The one consistent message I kept hearing from other attendees at Openworld this year was that a lot of sites seem to have run into performance problems when upgrading from 9i to 10g due to changes in the CBO and DBMS_STATS. Yes, there are some Oracle 9i databases out there, you know.

10.2.0.4 0

Via Laurent Schneider’s blog, it looks like 10.2.0.4 is out. I’ve just had a quick look on Metalink and unfortunately (but unsurprisingly) it doesn’t seem to be available for AIX just yet, just Linux, but it’s one we’ve been waiting for for a while, so it’s good to see the first signs.

Reviewing Parameter Files 0

One of the headline recommendations during the Real World Performance groups presentations at Openworld 2007 was to review your parameter files as part of your upgrade process. It sounds like simple common sense, but they suggested that inappropriate parameter settings that had been implemented during version 7 days for long forgotten reasons were often the root cause of performance problems on 9i or 10g databases that they were asked to investigate. One of their first actions was to review the parameters carefully and question them.

8 Useful Technical Posts … 0

That number in the title is not a joke or an attempt to drag out the pain. However, OraNA has been flooded with ‘8′ posts this week, so I thought it worthwhile to post a quick list of some really nice technical posts I’ve noticed over the last couple of weeks. I was just waiting for a weekend opportunity to clean out my pockets, so to speak.