Subject | RE: [ib-support] High CPU usage AFTER bulk insert completed |
---|---|
Author | Michael Grabinski |
Post date | 2002-03-21T03:03:02Z |
I've seen this behavior too, after turning forced-writes OFF and slamming
the database with a lot of inserts. You mentioned that forced-writes were
OFF for your database. I'd chalk up the "after the fact" processor activity
to Interbase finally getting around to writing your inserts to disk.
I imagine your insert statements return very quickly, but the data doesn't
actaully get written to disk until later. So Interbase is still chugging
away, writing to disk, even after your program has exited. I'll bet that
you would _not_ see the "after the fact" processor utilization if you turned
forced writes back ON. You'd probably see a 20x drop in performance though.
At least that's what I've seen in my testing, but what do I know :-)
-----Original Message-----
From: Kenneth Foo [mailto:kenneth@...]
Sent: Wednesday, March 20, 2002 7:06 PM
To: ib-support@yahoogroups.com
Subject: Re: [ib-support] High CPU usage AFTER bulk insert completed
the database with a lot of inserts. You mentioned that forced-writes were
OFF for your database. I'd chalk up the "after the fact" processor activity
to Interbase finally getting around to writing your inserts to disk.
I imagine your insert statements return very quickly, but the data doesn't
actaully get written to disk until later. So Interbase is still chugging
away, writing to disk, even after your program has exited. I'll bet that
you would _not_ see the "after the fact" processor utilization if you turned
forced writes back ON. You'd probably see a 20x drop in performance though.
At least that's what I've seen in my testing, but what do I know :-)
-----Original Message-----
From: Kenneth Foo [mailto:kenneth@...]
Sent: Wednesday, March 20, 2002 7:06 PM
To: ib-support@yahoogroups.com
Subject: Re: [ib-support] High CPU usage AFTER bulk insert completed
----- Original Message -----
From: "Ann W. Harrison" <aharrison@...>
To: <ib-support@yahoogroups.com>
Sent: Thursday, March 21, 2002 1:08 AM
Subject: Re: [ib-support] High CPU usage AFTER bulk insert completed
> Are you also doing a commit after each insert? That's making things
> slower than they need to be ... at least in most cases.
Yes, I did. :-)
I have a system that sends out messages and store some information in a DB
to keep track of messages that has been sent. In case of a server crash,
the system needs to know where it left off, thus the need for commits often.
Basically, I was testing the average sustained rate of insertion for FB.
But I didn't expect the processor usage to linger even after the operation
though.
I thought once commit has been performed, there aren't any more significant
cpu-intensive operations to perform?
> >Just wondering if this has something to do with some internal memory
> >management?
> >But then again, it's just 2000 prepared statements. It can't possibly
take
> >25 seconds to free them all right?
>
> Have you traced the memory usage of the server?
Well, I think it goes up till 144Mb, according to Windows Task Manager.
This on a machine with 384Mb RAM.
Regards
Kenneth
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