[TriLUG] OT: DBMS performance

David Brain dbrain at gmail.com
Wed Apr 4 14:53:48 EDT 2007


Hi,

Not sure about MySQL but for PostgreSQL (with a sensible config)  <1
second I would hope. Would depend on other factors obviously.

Just tried a query that returned 112 rows off an indexed field in a db
with 500k rows ~200ms - this is off fairly decent hardware, but
running in a Xen instance so disk IO not one of it's strong points.

If not indexed then it would end up doing a table scan, at which point
the size of the actual DB and IO bandwidth becomes the main factor.

David.

On 4/4/07, Steve Litt <slitt at troubleshooters.com> wrote:
> Hi all,
>
> From a MySQL or Postgres DBMS on a commodity machine (Athlon XP2600+ with
> 1.5MB RAM) that's not being used for anything else, running (Mandriva 2007)
> Linux, how fast should one be able to retrieve 5000 matching records out of
> 3.5 million total records? The matches match the field exactly (including
> capitalization).
>
> How long if the field being searched is indexed?
>
> How long if the field being searched is not indexed nor a primary key?
>
>
> Obviously the answers I'm looking for are very approximate. Would 5 seconds be
> good if it's indexed? If it's not indexed?
>
> How bout 1 second?
>
> Thanks
>
> SteveT
>
> Steve Litt
> Author: Universal Troubleshooting Process books and courseware
> http://www.troubleshooters.com/
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