[Xapian-tickets] [Xapian] #250: replace_document should make minimal changes to database file

[Xapian]

#250: replace_document should make minimal changes to database file
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 Reporter:  richard        |       Owner:  richard  
     Type:  enhancement    |      Status:  assigned 
 Priority:  normal         |   Milestone:  1.2.x    
Component:  Backend-Chert  |     Version:  SVN trunk
 Severity:  normal         |    Keywords:           
Blockedby:                 |    Platform:  All      
 Blocking:                 |  
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Comment(by richard):

 I've applied a patch for this (based originally on Kan-Ru's patch, but
 largely rewritten) to trunk in r13808.

 One point to note - for Flint, if the document length has changed, we need
 to update all the postings for that document, because the document length
 is stored in the posting entries.  This isn't an issue with Chert or
 Brass, which don't store the document length in posting entries.  For
 Flint, if the only changes are adding or removing of terms with 0 wdf, or
 more generally if the wdf change sums to 0, only those postings which have
 actually been changed will be applied, and the speedups should be visible.

 This largely fixes this ticket in trunk, though it would be good to make
 minimal changes to the value slots in Chert and Brass, in a similar manner
 to this.

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Ticket URL: <http://trac.xapian.org/ticket/250#comment:17>
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