Re: in-memory sorting

Samuel Gendler <sgendler@ideasculptor.com> writes:
> Answered my own question.  Cranking work_mem up to 350MB revealed that
> the in-memory sort requires more memory than the disk sort.

Yeah.  The on-disk representation of sortable data is tighter than the
in-memory representation for various reasons, mostly that we're willing
to work at making it small.  Datums aren't necessarily properly aligned
for example, and there's also palloc overhead to consider in-memory.

            regards, tom lane