View columns calculated

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От Peter Darley
Тема View columns calculated
Дата
Msg-id PDEOIIFFBIAABMGNJAGPEEGJDEAA.pdarley@kinesis-cem.com
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Ответы Re: View columns calculated  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-performance
Folks,
    I have a question about views:  I want to have a fairly wide view (lots of
columns) where most of the columns have some heavyish calculations in them,
but I'm concerned that it will have to calculate every column even when I'm
not selecting them.  So, the question is, if I have 5 columns in a view but
only select 1 column, is the system smart enough to not calculate the unused
columns, or am I taking a performance hit over a smaller view that doesn't
have the extra 4 columns?
Thanks,
Peter Darley


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