On Thu, Jan 7, 2010 at 2:02 PM, Mario Briggs <mario.bri...@in.ibm.com> wrote: > Russ, > > The indexing that Oracle is supporting is 'index-on-expression'. DB2 > also supports that, but it isnt enabled for character long columns, > since they hadnt had a request for that. I talked to the DB2 server > folks about these use-cases and they have agreed to support this via > index-on-expression shortly. For the immediate needs, Rahul is going > to look at supporting this via 'hidden' columns - Whenever there is a > text field with an index specified, the backend will create a hidden > and generated column (poplated with first X chars of the text field). > The index will be created on this hidden column. When there is a > lookup by value, the backend will actually do the lookup on the hidden > indexed column. - you see any blockers to this ?
I'm not sure what you're asking me. "Blockers" of what? I know almost nothing about DB2; I know only slightly more about Oracle. I can only advise you on what Django does. In this case, the code tells you everything you need to know: Django needs to be able to issue the following query: action_list = LogEntry.objects.filter( object_id = object_id, content_type__id__exact = ContentType.objects.get_for_model(model).id ).select_related().order_by('action_time') As long as you can satisfy that requirement, you've done everything you need to do. > BTW, index is not turned ON on LogEntry.object_id. Do you feel this > use-case usage is low to warrant that ? I can't say the lack of an index on that field has been a performance problem on any site I've managed, and I don't recall seeing any reports on the mailing list or Trac that indicate that it has caused a problem for anyone else. Yours, Russ Magee %-)
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