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

[Tim Cutts]

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


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