Re: SQL/MED - core functionality - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: SQL/MED - core functionality
Date
Msg-id 4D1219B8.9080609@dunslane.net
Whole thread Raw
In response to Re: SQL/MED - core functionality  (Simon Riggs <simon@2ndQuadrant.com>)
List 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


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