[Xapian-tickets] [Xapian] #224: Supply and optimise more OP_VALUE_ comparison operators

Xapian nobody at xapian.org
Mon Feb 1 01:36:18 GMT 2021


#224: Supply and optimise more OP_VALUE_ comparison operators
-----------------------------+-------------------------------
 Reporter:  Richard Boulton  |             Owner:  visvesh
     Type:  enhancement      |            Status:  new
 Priority:  low              |         Milestone:  1.4.x
Component:  Matcher          |           Version:  git master
 Severity:  minor            |        Resolution:
 Keywords:  GoodFirstBug     |        Blocked By:
 Blocking:                   |  Operating System:  All
-----------------------------+-------------------------------
Comment (by Olly Betts):

 The query optimiser would need to detect when there are two `OP_VALUE_*`
 subqueries on the same value slot in the same `AndContext` and create a
 single `PostList` object for the pair (instead of one for each as
 currently happens.)

 It probably ought to gather up all the subqueries on the same slot even if
 there are more than two, and eliminate any that are redundant - e.g. in `x
 >= 3 AND x > 2 AND x <= 4` we can ignore `x > 2` as it's ensured by `x >=
 3`.

 (That's "query optimiser" as in the parts of the code that optimises
 queries - it wouldn't necessarily be done in the `QueryOptimiser` class
 itself, though it might well be.)
-- 
Ticket URL: <https://trac.xapian.org/ticket/224#comment:14>
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