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From:David Johnson Date:June 22 1999 8:18pm
Subject:Re: Update,Insert and Select
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We are quickly running into the IO boundary problem.  We do allot of updates
and have recently figured out that we will run into the IO wall long before
we run into the CPU wall.

We would be VERY interested in avoiding that problem.


----- Original Message -----
From: Sasha Pachev <sasha@stripped>
To: <mysql@stripped>
Sent: Tuesday, June 22, 1999 6:55 AM
Subject: Update,Insert and Select

> I have been messing around with the following problem ( for educational
> purposes, not a production application):
> We have a table ip (ip int unsigned not null primary key, n not null).
> We generate random ips from a given range - if the record is already in
> the table we increment the counter - otherwise we perform an insert. We
> are trying to simulate a web counter database, so we do not lock tables
> to improve insert speed. The goal is to maximize performance ( number of
> queries per second).
> I have noticed that unlike selects, updates and inserts are more disk
> I/O than CPU bound. Setting key_buffer to 0 in this situation actually
> improved performance. Regardless of the buffer settings, disk I/O is
> very intensive and mysqld is using only a very small fraction of CPU.
> Does that mean that if someone is doing a lot of inserts and updates
> they need to focus on a fast disk? Or maybe there is a way to tweak the
> settings to avoid it (other than mounting ramdisk on
> /usr/local/mysql/data/db_name) What do you guys think?
> --
> Sasha Pachev
> (home)
> (work)
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Update,Insert and SelectSasha Pachev23 Jun
  • Re: Update,Insert and SelectDavid Johnson23 Jun
    • Re: Update,Insert and SelectDan Nelson23 Jun
  • Re: Update,Insert and SelectSasha Pachev23 Jun
  • Re: Update,Insert and SelectJim Faucette23 Jun
  • Update,Insert and SelectMichael Widenius29 Jun