[notmuch] Notmuch performance problems on OSX

[Olly Betts]

On 2010-02-09, Oliver Charles wrote:
> I just upgraded to xapian-core HEAD and notmuch master tip today, in
> desparation to get away from GMail. Sadly it's still taking at least
> 0.7s to tag a single thread (with one message). I'm really eager to
> solve this, could anyone give me any pointers on how I could go about
> profiling it or finding the cause of this problem?

The first thing to try is disabling use of F_FULLFSYNC.  You'll need to
run this command in the xapian-core source tree to comment out the F_FULLFSYNC
code:

perl -pi -e 's/^#ifdef F_FULLFSYNC/#if 0/' backends/*/*_io.h

Then run "make" and "make install".

This makes you a bit more vulnerable to power failures, but no worse than
a typical Unix system.  There's some background here:

http://lists.apple.com/archives/Darwin-dev/2005/Feb/msg00072.html

Assuming that helps, then (a) you have a workaround, and (b) we'll know for
sure it is F_FULLFSYNC to blame.

I've created a ticket for a change to Xapian which should help here, but
not had a chance to work on it yet:

http://trac.xapian.org/ticket/426

Cheers,
    Olly