Re: I almost dropped the system due to SQL using large amounts forresources

I have a customer with a 10 million record database, and a rpglesql
pgm for users to make selections, on a tiny system. Some selections include %like
which can force a table scan, but I made sure thru edits that
there had to be some selection (like customer) so that the %like
only gets executed when a single customer selected, a logical views exist for sql to not have to build a key. You might want to (if you have not already done this) analyze the file(s) and logicals so the system doesn't need to build large temporary structures.
jim franz
----- Original Message ----- From: "Tim Gornall" <tgornall@xxxxxxxxxx>
To: <midrange-l@xxxxxxxxxxxx>
Sent: Friday, May 30, 2008 10:46 AM
Subject: I almost dropped the system due to SQL using large amounts forresources

We have a SQLRPGLE program that dynamically builds the SQL statement based
on user imput. Sometimes the statement can fairly large and when it is it
uses very large amounts of both processing and storage resources. I have
seen it gobble up processer, but was surprised yesterday when I noticed the
the system ASP when through the roof. The ASP was up to 93 percent and
climbing when I got word. As soon as I ended the job the ASP came back down
almost immediately. I backed out the process completely until I can be
assured this won't happen again.

The job is run interactivly within an order entry process. We implemented
it last week and instantly noticed slow system response when large queries
are run. As a quick fix, I change the job priority within the program
before the sql runs and then change it back afterwards. This makes it run a
bit slower for the user but the system does not take the hit.

But now with the ASP issue, I need a real fix. Is there a way to to limit
the amount of resourses the job can alocate? Both processer and ASP.
Basically put some type of govenor on SQL. Idealy it would be a global
setting for all SQL run on the machine.

Thanks, Tim