From: Sebastien Binet <binet@cern.ch>
To: Austin Clements <amdragon@MIT.EDU>
Subject: Re: query on a subset of messages ?
In-Reply-To: <20120709163000.GG18195@mit.edu>
References: <871ukl5oj7.fsf@cern.ch> <20120709163000.GG18195@mit.edu>
User-Agent: Notmuch/0.13.2+60~g7ecf77d (http://notmuchmail.org) Emacs/24.1.1
	(x86_64-unknown-linux-gnu)
Date: Mon, 9 Jul 2012 19:06:37 +0200
Message-ID: <87obno3luq.fsf@cern.ch>
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1;
	protocol="application/pgp-signature"
Keywords: CERN SpamKiller Note: -50
Cc: Notmuch developer list <notmuch@notmuchmail.org>
Precedence: list

--=-=-=
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable

Austin Clements <amdragon@MIT.EDU> writes:

> Quoth Sebastien Binet on Jul 09 at 10:25 am:
>>=20
>> hi there,
>>=20
>> I was trying to reduce the I/O stress during my usual email
>> fetching+tagging by writing a little program using the go bindings to
>> notmuch.
>>=20
>> ie:
>> db, status :=3D notmuch.OpenDatabase(db_path,
>>     		notmuch.DATABASE_MODE_READ_WRITE)
>> query :=3D db.CreateQuery("(tag:new AND tag:inbox)")
>> msgs :=3D query.SearchMessages()
>> for _,msg :=3D range msgs {
>>   tag_msg(msg, tagqueries)
>> }
>>=20
>>=20
>> where tagqueries is a subquery of the form:
>> [
>>     {
>>         "Cmd": "+to-me",
>>         "Query": "(to:sebastien.binet@cern.ch and not tag:to-me)"
>>     },
>>     {
>>         "Cmd": "+sci-notmuch",
>>         "Query": "from:notmuch@notmuchmail.org or to:notmuch@notmuchmail=
.org or subject:notmuch"
>>     }
>> ]
>>=20
>>=20
>> the idea being that I only need to crawl through the db only once and
>> then iteratively apply tags on those messages (instead of repeatedly
>> running "notmuch tag ..." for each and every of those many
>> 'tag-queries')
>>=20
>> I couldn't find any C-API to do such a thing using the notmuch library.
>> did I overlook something ?
>>=20
>> Is it something useful to add ?
>>=20
>> -s
>
> Have you tried a more direct translation of the multiple notmuch tag
> commands into Go, where you don't worry about subsetting the queries?
> Unless you're tagging a huge number of messages, the cost of notmuch
> tag is almost certainly the fsync that it does when it closes the
> database (which every call to notmuch tag must do).  However, in Go,
> you can keep the database open across all of the tagging operations
> and then close and fsync it just once.

nope, I haven't tried that, but will do.

>
> Note that there is an important optimization in notmuch tag that you
> might have to replicate.  It manipulates the original query to exclude
> messages that already have the desired tags, so that they get skipped
> very efficiently at the earliest stage possible.
I already have this in my original shell script.
(wouldn't be too hard to automatically do, though.)

=2Ds

--=-=-=
Content-Type: application/pgp-signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.19 (GNU/Linux)

iEYEARECAAYFAk/7D50ACgkQPj4AVbsZCCbNJQCgt63SDJf50TSrnZ/j6szzYHsu
76EAoO3+PD1VEncWbu/uMckjhesXTOKu
=rRi9
-----END PGP SIGNATURE-----
--=-=-=--