On Tue, Dec 16, 2014 at 12:15 PM, Robert Haas <robertmh...@gmail.com> wrote: > <langote_amit...@lab.ntt.co.jp> wrote: >> Robert wrote: >>> On Sun, Dec 14, 2014 at 9:12 PM, Amit Langote >>> <langote_amit...@lab.ntt.co.jp> wrote: >>> > This means if a user puts arbitrary expressions in a partition >>> > definition, say, >>> > >>> > ... FOR VALUES extract(month from current_date) TO extract(month from >>> current_date + interval '3 months'), >>> > >>> > we make sure that those expressions are pre-computed to literal values. >>> >>> I would expect that to fail, just as it would fail if you tried to >>> build an index using a volatile expression. >> >> Oops, wrong example, sorry. In case of an otherwise good expression? > > I'm not really sure what you are getting here. An "otherwise-good > expression" basically means a constant. Index expressions have to be > things that always produce the same result given the same input, > because otherwise you might get a different result when searching the > index than you did when building it, and then you would fail to find > keys that are actually present.
I think the point is partitioning based on the result of an expression over row columns. Or if it's not, it should be made anyway: PARTITION BY LIST (extract(month from date_created) VALUES (1, 3, 6, 9, 12); Or something like that. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
