[rt-users] Severe performance problems suddenly in RT 3.8.2

[Kenneth Marshall]

On Wed, Feb 18, 2009 at 06:13:08PM +0000, Tim Cutts wrote:
> 
> On 18 Feb 2009, at 5:54 pm, Dave Holland wrote:
> 
> > On Tue, Feb 17, 2009 at 05:52:23PM -0500, Jesse Vincent wrote:
> >> An excellent question. I have a sneaking suspicion there's some DB
> >> corruption in there somewhere :/ But maybe it's just a database bug.
> >
> > After chasing some red herrings we found something "interesting":
> >
> > mysql> select count(*) from Attachments;
> > +----------+
> > | count(*) |
> > +----------+
> > |   807113 |
> > +----------+
> > 1 row in set (1 min 47.01 sec)
> >
> > mysql> select count(*) from Attachments ignore index(PRIMARY);
> > +----------+
> > | count(*) |
> > +----------+
> > |   807113 |
> > +----------+
> > 1 row in set (0.66 sec)
> >
> > So I did a quick "alter table Attachments drop primary key, add  
> > primary
> > key (id);" and now we are seeing much more sensible behaviour:
> >
> > mysql> select count(*) from Attachments;
> > +----------+
> > | count(*) |
> > +----------+
> > |   807568 |
> > +----------+
> > 1 row in set (0.00 sec)
> >
> > There is still an occasional hiccup when it goes slower - possibly  
> > when
> > an Attachment has been added - but by and large it's working as  
> > expected
> > now.
> >
> > Thanks everyone for your help, I've learned rather a lot about MySQL  
> > in
> > the last day or so!
> 
> Should add that any form of full text search of Content is still  
> taking so long that the web interface times out, and in some browsers  
> this can then have a nasty effect on the session and you can't open  
> any more RT windows without shutting down your browser (behaviour seen  
> on both IE and Firefox)
> 
> Tim
> 

Tim,

That is a consequence of the I/O needed versus the performance of your
I/O subsystem. If full text search of content is needed I would recommend
using a backend database with that support. Currently there are two
recipes on the wiki for adding that support to Oracle and PostgreSQL. I
am biased,  but the PostgreSQL recipe is extremely easy to set up and
preforms wonderfully -- but I am biased. :)

Cheers,
Ken