Re: lastmod based on date/time

[David Bremner <david@tethera.net>]

Al Haji-Ali <abdo.haji.ali@gmail.com> writes:

> Would it be possible to search for lastmod messages based on time
> rather than revision ID?  Using revision ID is convenient for
> tools/scripts, but not for actual everyday use.
>

The modification time is not saved in the database.

> I sometimes find myself needing to find a message that I accidentally
> archived/moved and it would be convenient if I can list all the
> messages that I modified (tag or otherwise) in the past day for
> example. I currently use the current value of revision ID minus a few
> hundreds as a proxy for time.

A workaround could be to run a cron job or equivalent that logs
(lastmod,timestamp) pairs to a file. Of course that would make using the
information a bit inconvenient without further tooling.

Because of concerns about performance, we have so far resisted having a
"tagging hook".  'lastmod:' was added at some point because it addressed
some of the usecases for a tagging hook.

At the time (2014) we chose the counter approach over timestamps because
of the difficulty of synchronizing clocks between machines and the
possibility of clock changes on a given machine [1]. In principle
modification timestamps could be added as additional data for each
message. I'm not sure about the cost/benefit here (either for
implementation or performance) but if someone wants to investigate
further I can point them in the right direction (mostly, copy the
lastmod stuff).

[1]: I think most of the discussion is in the thread 
https://nmbug.notmuchmail.org/nmweb/show/1396800683-9164-1-git-send-email-eg%40gaute.vetsj.com