Re: SQL/MED - core functionality

Andrew Dunstan <andrew@dunslane.net>

From: Andrew Dunstan <andrew@dunslane.net>
To: Simon Riggs <simon@2ndQuadrant.com>
Cc: Shigeru HANADA <hanada@metrosystems.co.jp>, pgsql-hackers@postgresql.org
Date: 2010-12-22T15:31:04Z
Lists: pgsql-hackers

On 12/22/2010 10:00 AM, Simon Riggs wrote:
> 7. Why does ANALYZE skip foreign tables? Surely its really important we
>>> know things about a foreign table, otherwise we are going to optimize
>>> things very badly.
>> Quite apart from other reasons, such as possible ephemerality of the
>> data, the difficulty of taking a reasonable random sample from an
>> arbitrary foreign data source seems substantial, and we surely don't
>> want ANALYSE to have to run a full sequential scan of a foreign data source.
> I think we need something that estimates the size of a table, at least,
> otherwise queries will be completely un-optimised.
>
>

Perhaps we could allow FDWs to register a size estimation function. Does 
this need to be done on the first go round? Time is running a bit short.

cheers

andrew