[Xapian-tickets] [Xapian] #671: Performance issues when querying over large number of local databases (shards)

[Xapian]

#671: Performance issues when querying over large number of local databases
(shards)
----------------------------------+--------------------------
 Reporter:  wgreenberg            |             Owner:  olly
     Type:  defect                |            Status:  new
 Priority:  normal                |         Milestone:
Component:  Matcher               |           Version:
 Severity:  normal                |        Resolution:
 Keywords:  sharding performance  |        Blocked By:
 Blocking:                        |  Operating System:  Linux
----------------------------------+--------------------------

Comment (by wgreenberg):

 Thanks for the feedback. I amended the patch to only readahead the top
 level of the B-tree, and removed some of the unnecessary cruft I copied
 from ::find.

 I removed the stateful changes to the current cursor since, if I
 understand this right, there's no reason the readahead method should alter
 cursor state at all. strace again verifies that this patch reads the
 correct blocks (even for multi-term queries).

 I'll try to get another patch in which does a similar readahead
 optimization for record.DB lookups (using fetch, as per IRC discussion
 with olly).

--
Ticket URL: <http://trac.xapian.org/ticket/671#comment:6>
Xapian <http://xapian.org/>
Xapian