On Fri, Jun 18, 2010 at 2:36 PM, mac_man2005@hotmail.it
<mac_man2005@hotmail.it> wrote:
> Please take a look at the initial comment contained into the logtape.c file:
> http://doxygen.postgresql.org/logtape_8c-source.html
>
> Almost at the beginning of that file, it is affirmed that implementing tapes
> on disk (quote: by creating a separate file for each "tape") will require
> more space than implementing merge on tapes themselves.
> Now, taking in account that tuplesort.c and logtape.c actually DO implement
> tapes on disk, in which case it would require between 2x and 4x the input
> space?
Did you read the rest of the comment? It explains how the code avoids this...
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company