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[Bug 641198] Re: Prefix search is not using an index

 

** Attachment added: "glob-index-test.py"
   https://bugs.edge.launchpad.net/bugs/641198/+attachment/1597664/+files/glob-index-test.py

** Changed in: zeitgeist
       Status: New => In Progress

** Changed in: zeitgeist
     Assignee: (unassigned) => Markus Korn (thekorn)

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Prefix search is not using an index
https://bugs.launchpad.net/bugs/641198
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Status in Zeitgeist Framework: In Progress

Bug description:
In the prefix search we are using a 'GLOB' sql-statement, this statement is not using the index and thus slow, some timings from me running the attached script:

* Database with ~50k events
* ~1% of these event have a subject with uri beginning with 'http://aa'

* searching for all uris beginning with 'http://aa' using the 'GLOB' expression (what we have now in lp:zeitgeist) takes ~0.03 sec
* changing this query to some (x >= S AND x < T) statement reduces this time to ~0.002 sec

This is easy to implement (and test) for ascii chars, but as we support unicode esp. testing seems to be a bit tricky





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