feature request: caching message arrival time

[David Bremner]

Daniel Kahn Gillmor <dkg at fifthhorseman.net> writes:

>  * i don't think we have a way to search properties by range (e.g. the
>    way that we can search date ranges).  i don't need that feature for
>    my use case, but maybe someone will come up with a use case that
>    wants it?  is there a way to store the datestamp in a way that it can
>    be scanned the way that "date" can?  or do we already have this and
>    i'm just unaware?

you'd need to use a value slot to get (native Xapian) range
searches. To quote the xapian docs

      For performance it is important to keep the amount of data stored
      in the values to a minimum, since the values for a large number of
      documents may be read during the search - the more data that has
      to be read, the slower the search will be.

So it's definitely something that would need to be profiled.

Probably the patches that added lastmod: are a good example for someone
wanting to investigate this.