On 4 October 2016 at 12:47, Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>> Why not just make each new run start at a block boundary?
>> That way we waste on average BLCKSZ/2 disk space per run, which is
>> negligible but we avoid any need to have code to read back in the last
>> block.
>
>
> Hmm. You'd still have to read back the last block, so that you can update
> its next-pointer.
If each run is in its own file, then you can skip that bit.
And we do want the sort to disk to use multiple files so we can
parallelize I/O as well as CPU.
So since we know we'll want multiple files, we should be thinking
about how to split things up between files.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
