Thread: Interaction between Free Space Map an alternate location for a database
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
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
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
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:
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
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:
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 ---------------------------(end of broadcast)--------------------------- TIP 7: don't forget to increase your free space map settings
-- Dave Cramer http://www.postgresintl.com 519 939 0336 ICQ#14675561