Notmuch new speed degradation

[Austin Clements]

Quoth Dmitry Bogatov on Jul 24 at 12:19 pm:
> Hello!
> 
> I have ~ 3 000 000 mails. I wanted to index them.
> First 1 000 000 took several hours, next 200 000 took several days.
> 
> And now, even with libeatmydata, it takes ~ 4 sec for a file.
> 
> Is it any way I can improve perfomance?
> 
> PS. Please, keep me in CC.

Hi Dmitry.  My guess is that's you've exceeded your OS buffer cache
size by enough that most B-tree reads are going to disk at least once.
How big is your database (du -h $MAIL/.notmuch/xapian) and what does
free -h report on that computer?  Also, is this on an SSD or an HDD?

You could try running notmuch compact.  That should shrink the
database, and, more importantly, pack more into the active page set
and, I think, also linearize the database.