Re: Memory Performance?

Thomas,

Well, remember that the keep buffer has to be loaded. So the first query is probably still pulling data from the tablespace. However, queries after that should be pulling data from the keep buffer.

Also, make sure that your keep buffer is big enough for all the data you're trying to load.

We did a search engine application for one of our web site clients and we added a procedure to the database startup scripts that primed the keep buffer cache to get things pre-loaded prior to actual hits by the users. We load the huge keep buffer with not only table data but also indexes as well. Performance, is pretty darn good. But, i would encourage you to check your queries with the sql*plus autotrace option taking advantage of the various hints will do. Sometimes you think one sql/hint combo method should be faster but with a little playing...you find unexpected combo gives better performance.

Anyway... that's my 2 cents.

Good luck,
Allen
http://hayden.home.mindspring.com

harrisjd_at_pluto.njcc.com wrote in message <38d07c5d.4174263_at_129.250.35.141>...
>A have a question, something that has been bugging me for some time
>across all platforms....
>
>Generally speaking, let's suppose....
>
>1. you have a SQL statement that performs a full table scan
>2. you run it once, it comes back in say 60 seconds.
>3. you run it again, and lets say it comes back in 30 seconds, a 200%
>improvement.
>4. Ok, now you decide to implement a KEEP pool large enough to hold
>the entire table.
>5. Shutdown and restart the instance/server/etc, run the same
>statement again.
>
>The timings are identical.
>
>Therefor, I am forcing the table to be in RAM. I can verify it with
>consistent gets. I am on a local wire, so the network performance
>is not an issue. I am on a quiet box, so the box is not loaded. RAM
>is ok on the box.
>
>If RAM is supposed to be at least 1000x faster than DISK (not adding
>in rotational delay, etc.), why don't I get at least 1000x the
>performance???
>
>Let me also say that from my experience, I have also seen this
>disparity. I have several production systems utilizing multiple
>buffer pools, and every other conceivable performance parameter in
>them with 99.9% hit ratios and the performance isn't that different
>from when the instance first starts or after a week after it has been
>running.
>
>This has plagued me since DBASE 3+ for a PC. For example, I setup a
>virtual drive large enough to hold the databases, indexes and
>application code, and again performance never knocked my socks off.
>
>Any insight as to why this is so?
>
>
>-Jerry
>
>P.S. Can you please reply to my email in addition to the newsgroup?
>I do not check the news groups regularly.
Received on Thu Mar 16 2000 - 00:00:00 CST