[FEATURE] Purge ignored messages from index

[David Bremner]

Markus Weimar <markus.weimar at gmail.com> writes:

> On Thu, 2018-11-22 16:49:56 -0400, David Bremner wrote:
>> Notmuch new works very hard to not visit files that haven't
>> changed. Changing this would have a big negative performance impact, afaik.
>
> I see. I thought it might be possible to purge the entries without
> looking at any files by doing a cheap comparison of indexed file path
> against ignored patterns. If that’s not possible, I agree that ´new´
> shouldn’t be slowed down for this edge case.
>

File paths aren't really indexed, only the directory part.

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