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