Re: WIP Patch: Use sortedness of CSV foreign tables for query planning

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: "Etsuro Fujita" <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp>, "'PostgreSQL-development'" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: WIP Patch: Use sortedness of CSV foreign tables for query planning
Date: 2012-08-02 16:28:53
Message-ID: 501A64750200002500049353@gw.wicourts.gov
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"Etsuro Fujita" <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp> wrote:

> I would like to propose single-column sortedness options and
> insert appropriate pathkeys into the ForeignPath node based on
> these information:
>
> sorted: Boolean option to specify whether data file is sorted by
> a column.
> key: Specifies the name of a column by which data file is sorted.
> Required when the above option is set to true.
> direction: Specifies the sort order: asc or desc. The default is
> asc.
> nulls: Specifies that nulls sort before or after non-nulls: first
> or last. first is the default when direction option is set
> desc. When direction option is not set desc, last is the
> default.

For character-based columns, don't we need to know the collation?

-Kevin

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