Rainer Bauer <usenet@munnin.com> writes:
> Erik Jones wrote:
>> What temporary created data are you referring to?
> The one described in the manual
> <http://www.postgresql.org/docs/8.2/static/sql-cluster.html>:
> "During the cluster operation, a temporary copy of the table is created that
> contains the table data in the index order. Temporary copies of each index on
> the table are created as well."
That's probably a bit misleading. There is no "temporary" copy of the
table, just the new permanent copy. The document is trying to point out
to you that the transient disk space requirement will be 2X the table
size, but maybe we could phrase it better.
For btree indexes, there is a temporary copy of the index data, which
will go wherever you have arranged for temp files to go. (I think that
easy user control of this may be new for 8.3, though.)
regards, tom lane