Re: Problem with large query - Mailing list pgsql-performance

From Adam Sah
Subject Re: Problem with large query
Date
Msg-id 413F1B85.9040302@speakeasy.net
Whole thread Raw
In response to Re: Problem with large query  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
by the way, this reminds me: I just ran a performance study at a company doing
    an oracle-to-postgres conversion, and FYI converting from numeric and decimal
    to integer/bigint/real saved roughly 3x on space and 2x on performance.
    Obviously, YMMV.

adam


Tom Lane wrote:

> Marc Cousin <mcousin@sigma.fr> writes:
>
>>I'm having trouble with a (quite big) query, and can't find a way to make it
>>faster.
>
>
> Seems like it might help if the thing could use a HashAggregate instead
> of sort/group.  Numeric is not hashable, so having those TO_NUMBER
> constants in GROUP BY destroys this option instantly ... but why in the
> world are you grouping by constants anyway?  You didn't say what the
> datatypes of the other columns were...
>
>             regards, tom lane
>
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