[Xapian-tickets] [Xapian] #450: wdf_upper_bound is not always correct on WritableDatabase

[Xapian]

#450: wdf_upper_bound is not always correct on WritableDatabase
---------------------------+------------------------------------------------
 Reporter:  richard        |       Owner:  olly     
     Type:  defect         |      Status:  new      
 Priority:  normal         |   Milestone:  1.1.5    
Component:  Backend-Chert  |     Version:  SVN trunk
 Severity:  normal         |   Blockedby:           
 Platform:  All            |    Blocking:           
---------------------------+------------------------------------------------
 If get_wdf_upper_bound() is called on a WritableDatabase when unflush
 modifications have been made to a term, an incorrect bound can be
 returned.

 For example, I will attach a patch to tests/dbcheck.cc which makes it
 check the consistency of bounds.  If the patch is applied to SVN trunk,
 various testcases will fail: for example, modtermwdf1 will fail at line
 135 with the error:

 {{{
 /home/richard/private/Working/xapian/trunk/xapian-
 core/tests/dbcheck.cc:276: (wdf_upper_bound) <=
 (db.get_wdf_upper_bound(*t))
 Evaluates to: 2 <= 0
 }}}

 Adding further debugging shows that this is testing the bound for the term
 "takeaway", for which the posting list contains one entry with wdf 2, so
 db.get_wdf_upper_bound(*t) should be returning at least 2.

-- 
Ticket URL: <http://trac.xapian.org/ticket/450>
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