Re: Free Space Map thoughts - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Free Space Map thoughts
Date
Msg-id 1194600568.4251.372.camel@ebony.site
Whole thread Raw
In response to Re: Free Space Map thoughts  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: Free Space Map thoughts  (Heikki Linnakangas <heikki@enterprisedb.com>)
List pgsql-hackers
On Thu, 2007-11-08 at 21:50 -0300, Alvaro Herrera wrote:
> Simon Riggs wrote:
> 
> > Presumably we would not store an FSM for small tables? On the basis that
> > the purpose of the FSM is to save on pointless I/O there must be a size
> > of table below which an FSM is just overhead.
> 
> Hmm, do you mean that we would open and verify every page of a small
> relation until we find one with free space?  That doesn't sound very
> good.

I was trying to guess at Heikki's reason for saying the FSM should be in
a separate file. If we have one extra file per table that seems like a
huge number of additional files, with space and fsync implications.
Let's wait and see what Heikki's answer is.

--  Simon Riggs 2ndQuadrant  http://www.2ndQuadrant.com



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