On Mon, 12 Apr 2010 15:33:35 +0200, "Sebastian Spaeth" <Sebastian@SSpaeth.de> wrote:
> fsync is really killing xapian (and notmuch). What suffers, are the
> boolean prefixes (tag, id, and thread). Using libeatmydata (which
> disables fsync) shows a 10x speedup for tagging. The speedup is only
> factor 2 for e.g. from: searches. This is ext4 on recent stock
> Ubuntu. Given that search by tag and thread are performed really often
> (each time I advance a thread, for example), that really hurts.

Wow, this is really interesting, Sebastian.  For those of us not in the
know, can you explain what libeatmydata is and how it's used?  It sounds
like something I would *not* want to use!  So you didn't have to
recompile here, and only had to set LD_PRELOAD=./libeatmydata.so?  Is
there any drawback to what you're doing here?

jamie.