Re: 10g Memory Usage: 12 GB RAM & 5000 Connections ~ Need help understanding

Thanks for the reply.

> If you take 8 gig for SGA and 4 gig for memory for oracle.exe doesn't
> that get you up to your 12 gig?

Yes, it does. I'm just wondering what the 4 GB allocated is being used for. 8G for SGA, plus 2 more reserved to get to SGA_MAX of 10G. The other 2 GB is being reserved/used for ... ?

> Many people with servers that have this much RAM might consider
> supporting 5000 connections with dedicated server.

Yes, I tried playing around with that. I'm messing with different memory configurations: SGA_Target = 6G, 8G, 10G to see what the limits are for connections. It's just preliminary testsing. With SGA=6G I was getting about 3000 dedicated connections. We moved to shared server to get around the 32-bit addressable memory limit. These tests are to see just how many connections we can get overall.

> A lot of swapping?

Well, I didn't see any. I was following a Microsoft document on how to size your pagefile. I have max 18GB of page files. (Rule of thumb of 1 - 1.5x physical RAM).

> Sorry we don't run windows here for oracle but wouldn't you want a
> higher number for available memory on a machine that has this much
> memory?

Oracle is the only thing we're running on this server, so it doesn't really matter. But, yes. Available memory was generally in the hundreds of megs, but never got below 60M. Microsoft's docs say not to let it get below 4MB.

> Current oracle performance tuning thinking discounts the useability of
> cache hit ratios but one that is that high makes me wonder if you have
> way too much memory devoted to it. If you cut your buffer cache down
> by 50% do you still get 99.9 percent?

Interesting idea. I haven't tried as I've used the automatic memory management thus far.

Thanks, again. Received on Wed Jun 28 2006 - 12:49:26 CDT