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From Nick North <nort...@gmail.com>
Subject Re: Replication of attachment is extremely slow
Date Fri, 24 Jan 2014 13:06:33 GMT
On 24 January 2014 12:44, Dave Cottlehuber <dch@jsonified.com> wrote:

> On 24. Jänner 2014 at 08:23:16, Nick North (north.n@gmail.com) wrote:
> > From: Nick North <north.n@gmail.com>
>
> > There is a known inefficiency
> > in parsing of attachments containing certain character strings.
> > This doesn't obviously sound like an instance of it, but you can
> > eliminate the possibility very quickly if you replace all hyphens
> > (i.e. the character "-") in your mixed content file by some other
> > character, like "X". If replication of the modified file runs
> > quickly, you've hit this particular problem.
> > Nick
>
> Hey Nick, https://issues.apache.org/jira/browse/COUCHDB-1953 thanks
> for bringing that up. I’ve quickly re-done my timing checks with that
> and see no major difference, do you want to compare a few with some
> other modified test docs and see how that looks?
>
> A+
> Dave
>
>
I'm not really expecting this problem to be the cause of the slowdown:
the attachment needs to contain a lot of initial prefixes of the MIME
boundary string for things to be really bad. While the patch speeds up
parsing in all cases, I suspect the processing time is usually dominated by
other parts of the process. I just mentioned it as it's the only bit of
code I know whose performance varies with attachment content, so it's worth
a try. It would be great if Scott is able to put his offending file up
somewhere for us to try out.

Nick

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