Re: patch: SQL/MED(FDW) DDL

Excerpts from Robert Haas's message of mar sep 28 10:26:54 -0400 2010:

> Then:
>
> - Begin a sequential scan with the following set of quals.
> - Begin an index scan using the index called X with the following set of quals.
> - Fetch next tuple.
> - End scan.

I'm not sure that it's a good idea to embed into the FDW API the set of
operations known to the executor. For example your proposal fails to
consider bitmap scans. Seems simpler and more general to hand the quals
over saying "I need to scan this relation with these quals", and have it
return an opaque iterable object; the remote executor would be in charge
of determining their usage for indexscans; or even for filtering tuples
with quals that cannot be part of the index condition.

There doesn't to be much point in knowing the names of remote indexes
either (if it came to referencing them, better use OIDs)

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Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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