Fwd: Re: [rt-users] Re: Does Postgres offer acceptable performance

Jamie Lawrence rtusers-lists-fsck-com at jal.org
Thu Dec 11 08:50:48 EST 2003


> Alek Cesarz <acesarz at crowley.pl> writes:
> 
> > Andrew J. Korty wrote, On 2003-12-11 13:29:
> >
> >> I'm a long-time PostgreSQL user, but it was intolerably slow with a
> >> 30,000-ticket RT database.  Even after a *lot* of tuning (server
> >> parameters, custom indexes, etc.), certain queries, especially large
> >> joins, took minutes to complete.  Other folks seem to have no
> >> problems, though, so maybe I missed something.

If you haven't done a vaccum analyze in a while, it might help.
</end-stock-advice> Note that PG 7.4 can automatically vaccum the DB. I
haven't upgraded yet, but 7.4.1 is (hopefully) coming out on the 15th,
with most of the point release bugs quashed.

> > same issue here. but migrating to mysql did not help much. it looks as
> > it is not a matter of database, but more like perl DBD/DBI modules issue.
> > when i look at cpu util, i notice db taking ~50% for 10-20 seconds and
> > after that apache is going to the roof (97%) for next 10 minutes.
> 
> I haven't seen that behavior, and MySQL is generally faster for us.
> But searching attachment content is still unusably slow.  I'm guessing
> it doesn't help that we're not using any indexing on the attachment
> content and that we're treating all attachments the same.  So if
> someone sends us a big binary file, we're searching it every time.

I've been wondering what was going to happen with a lot of tickets and
attachment searching. It is a full table scan, which won't be good in
any DBMS.

I was thinking of modifying RT to use either the PG contrib/FTI or
a similar setup we built to create a full text index. If anyone is 
interested, I'll move that up my list of things to do (although 
not very far... things to do). It would be possible to skip 
binary files (at least with our tool), but better would be a patch to 
stick them in a separate table. 

DBI shouldn't be a bottleneck on joins - all it is doing is passing the
query through. I haven't looked at the queries RT is writing -
anyone know where they live?

-j

-- 
Jamie Lawrence                                        jal at jal.org
...and then I said, "That's no tissue sample, it's a prime rib steak!"




----- End forwarded message -----



-- 
Jamie Lawrence                                        jal at jal.org
"Perl is Internet Yiddish."
   - Yoz Graehme





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