It will be convenient not to have to construct a notmuch query object
when parsing subqueries, so the commit rewrites the query
expansion (currently only used for thread:{} queries) using only
Xapian. As a bonus it seems about 15% faster in initial experiments.
Xapian 1.4 is over 3 years old now (1.4.0 released 2016-06-24),
and 1.2 has been deprecated in Notmuch version 0.27 (2018-06-13).
Xapian 1.4 supports compaction, field processors and retry locking;
conditionals checking compaction and field processors were removed
but user may want to disable retry locking at configure time so it
is kept.
The observation is that we are only using the messages to get there
thread_id, which is kindof a pessimal access pattern for the current
notmuch_message_get_thread_id
This change allows queries of the form
thread:{from:me} and thread:{from:jian} and not thread:{from:dave}
This is still somewhat brute-force, but it's a big improvement over
both the shell script solution and the previous proposal [1], because it
does not build the whole thread structure just generate a
query. A further potential optimization is to replace the calls to
notmuch with more specialized Xapian code; in particular it's not
likely that reading all of the message metadata is a win here.
[1]: id:20170820213240.20526-1-david@tethera.net
This change allows queries of the form
thread:{from:me} and thread:{from:jian} and not thread:{from:dave}
This is still somewhat brute-force, but it's a big improvement over
both the shell script solution and the previous proposal [1], because it
does not build the whole thread structure just generate a
query. A further potential optimization is to replace the calls to
notmuch with more specialized Xapian code; in particular it's not
likely that reading all of the message metadata is a win here.
[1]: id:20170820213240.20526-1-david@tethera.net
