[Info-Ingres] Invalidate cache

[Cecil Westerhof]

Roy Hann wrote:

> "Cecil Westerhof" <dummy at dummy.nl> wrote in message
> news:46512088$0$320$e4fe514c at news.xs4all.nl...
>> Roy Hann wrote:
>>
>>> "Cecil Westerhof" <dummy at dummy.nl> wrote in message
>>> news:465018e1$0$337$e4fe514c at news.xs4all.nl...
>>>
>>> If you have permission to run the accessdb utility, go into the "Users"
>>> submenu, choose your user ID to edit it, and set the "Set trace flags"
>>> switch to "y".  Don't forget to save the change.  Log back in to pick up
>>> the new privilege.
>>
>> This works. Thanks.
> 
> Good.
> 
>> But it gives a new question.
>> I run my queries on a machine that is doing nothing except executing my
>> queries. Before every query I execute
>>        SET TRACE POINT DM421
>> But still there is a big difference between the queries. For example when
>> executing one of the old queries five times it takes: 355,97, 690,16,
>> 379,51, 100,27 and 60,96. When I execute the new version it takes: 2,60,
>> 10,57, 0,99, 0,74, and 1,01 seconds. So it is save to say the new query
>> is faster, but it is not clear by which factor. In the old query the
>> difference between the fastest and slowest is 11,3 and in the new query
>> it is 14,3. Is this normal?
> 
> You say you are running the same query repeatedly.  Is it exactly the same
> query each time, with exactly the same constants in the WHERE clause each
> time?   I have no explanation for why there would be a difference each
> time if it is the same query, except that perhaps the host machine is
> *very* busy doing other things as well.

Yes, the script generates a SQL-statement and this is executed repeatadly.
The host machine is only executing VMware. And the virtual machine is only
executing the sql-query.

I'll will make a simpler version of the script and post it here.


> There are a couple of presentations on our website that may be of use to
> you.  Go to www.rationalcommerce.com and click on the Presentations link,
> and from there download "Doing More with QEPs than Just Gawping" and "High
> Performance Batch Applications".

I'll look.