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author | Bruce Momjian | 2004-04-20 01:00:26 +0000 |
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committer | Bruce Momjian | 2004-04-20 01:00:26 +0000 |
commit | 6ef77149f7ed29d65096b126d9b062dc110b5b74 (patch) | |
tree | 32e2691cfecb4b5b8dca74cfa70a0b16a7f31905 /doc/FAQ_AIX | |
parent | 6949fc0269e0686bb3dd1d2b0d73a653f843705b (diff) |
> >> My question is whether postgres can index null values, and if not, do I
> >> have to accept a full table scan when locating records.
> >
> > It indexes them, but "is null" is not an indexable operator, so you
> > can't directly solve the above with a 3-column index. What you can do
> > instead is use a partial index, for instance
> >
> > create index i on CUSTOMER.WCCustOrderStatusLog (WCOrderStatusID)
> > where Acknowledged is null and Processing is null;
>
> That's a very nifty trick and exactly the sort of answer I was after!
Add CREATE INDEX doc mention of using partial indexes for IS NULL
indexing; idea from Tom.
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