Re: About tapes

On Fri, Jun 18, 2010 at 3:11 PM, mac_man2005@hotmail.it
<mac_man2005@hotmail.it> wrote:
> Il 18/06/2010 21:00, Robert Haas ha scritto:
>>
>> On Fri, Jun 18
>> Did you read the rest of the comment?  It explains how the code avoids
>> this...
>>
>>
>
> Robert, thanks for your reply.
> I read the rest of the document, but please take in account that my question
> wasn't about "avoiding".
> My question is "in which cases"?
>
> I repeat my question. Tuplesort.c and logtape.c DO implement tapes on disk
> and currently they do not request 2x or 4x of the input space: so, again, in
> which case implementing tapes on disks requires between 2x and 4x of input
> space?

I think that the comment is saying that it *would* take 2x or 4x the
input space IF we created a separate file for each input.  So instead
we don't.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company