[Xapian-tickets] [Xapian] #333: Keep track of last modification time of database

[Xapian]

#333: Keep track of last modification time of database
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 Reporter:  richard        |        Owner:  olly     
     Type:  enhancement    |       Status:  new      
 Priority:  normal         |    Milestone:           
Component:  Backend-Chert  |      Version:  SVN trunk
 Severity:  normal         |   Resolution:           
 Keywords:                 |    Blockedby:           
 Platform:  All            |     Blocking:           
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Comment(by olly):

 Not sure I buy the status information use really - I kind of feel you're
 scratching around for a second use there!

 But a way to determine if a previous query might return different results
 now would be handy.  Not just for the HTTP if-modified-since, but for
 general caching of results - e.g. you could cache rendered output from
 Omega along with the timestamp.  Hmm, actually just being able to read the
 current revision would be enough for that, but that doesn't seem to
 provide an easy way to implement the HTTP if-modified-since case.  But
 using a timestamp is a bit brittle if the HTTP server and Xapian server
 are on different machines as there's potential for clock skew.

 Acutally, isn't the timestamp of the newer base file of the record table a
 reliable timestamp, even in the face of failed updates?  It won't be quite
 right after xapian-compact as record isn't updated last there, but it will
 just be a bit too old.  The major advantage of this approach is that it
 will work for existing databases, both flint and chert.

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Ticket URL: <http://trac.xapian.org/ticket/333#comment:1>
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