Thread: Interaction between Free Space Map an alternate location for a database

Interaction between Free Space Map an alternate location for a database

From
Dave Cramer
Date:
Can someone explain how the free space map deals with alternate database
locations?

Given that the free space map is global, and it is ostensibly managing
free disk space, how does it deal with tuples across disk locations ?


Dave

--
Dave Cramer
http://www.postgresintl.com
519 939 0336
ICQ#14675561


Re: Interaction between Free Space Map an alternate location for a database

From
Josh Berkus
Date:
Dave,

> Given that the free space map is global, and it is ostensibly managing
> free disk space, how does it deal with tuples across disk locations ?

Are you talking Tablespaces?

--
Josh Berkus
Aglio Database Solutions
San Francisco

Re: Interaction between Free Space Map an alternate location for a database

From
Tom Lane
Date:
Dave Cramer <pg@fastcrypt.com> writes:
> Can someone explain how the free space map deals with alternate database
> locations?

It doesn't really care.  It identifies tables by database OID+table OID,
and where they happen to sit physically doesn't matter.

            regards, tom lane

Re: Interaction between Free Space Map an alternate location

From
Dave Cramer
Date:
No, have a look at the create database command

there is a clause 'with location' that allows you to set up a separate location for the db

Dave

Josh Berkus wrote:
Dave,
 
Given that the free space map is global, and it is ostensibly managing
free disk space, how does it deal with tuples across disk locations ?   
Are you talking Tablespaces?
 

-- 
Dave Cramer
http://www.postgresintl.com
519 939 0336
ICQ#14675561

Re: Interaction between Free Space Map an alternate location

From
Dave Cramer
Date:
Ok, so the global part of the fsm is just that it is in shared memory.  If certain databases have more
free space they will simply take up more of the fsm. There is no cross database movement of tuples.
( I realized this when I tried to form my next question)

Dave

Tom Lane wrote:
Dave Cramer <pg@fastcrypt.com> writes: 
Can someone explain how the free space map deals with alternate database 
locations?   
It doesn't really care.  It identifies tables by database OID+table OID,
and where they happen to sit physically doesn't matter.
		regards, tom lane

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-- 
Dave Cramer
http://www.postgresintl.com
519 939 0336
ICQ#14675561