[Info-Ingres] Invalidate cache

[Roy Hann]

"Cecil Westerhof" <dummy at dummy.nl> wrote in message 
news:46551cbd$0$327$e4fe514c at news.xs4all.nl...
> 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.

I think you should do that, because I am either not understanding the 
description of the problem, or there is something really strange happening 
on your system.   You should see very consistent response time unless there 
is a lot of lock-contention with sessions using exclusive locks on the same 
table/page.

Roy