On 15.09.2013 03:14, Alvaro Herrera wrote:
+ Partial indexes are not supported; since an index is concerned with minimum
and
+ maximum values of the involved columns across all the pages in the table, it
+ doesn't make sense to exclude values. Another way to see "partial" indexes
+ here would be those that only considered some pages in the table instead of
all
+ of them; but this would be difficult to implement and manage and, most likely,
+ pointless.
Something like this seems completely sensible to me:
create index i_accounts on accounts using minmax (ts) where valid = true;
The situation where that would be useful is if 'valid' accounts are
fairly well clustered, but invalid ones are scattered all over the
table. The minimum and maximum stoed in the index would only concern
valid accounts.
- Heikki
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