> Sure, but bulk load + reandom selects is going to *guarentee*
> fragmentatioon on a COW system (like ZFS, BTRFS, etc) as the selects
> start to write out all the hint-bit-dirtied blocks in random orders...
>
> i.e. it doesn't take long to make an originally nicely continuous block
> random....
I'm testing with DD and Bonnie++, though, which create their own files.
For that matter, running an ETL procedure with a newly created database
on both recordsizes was notably (2.5x) faster on the 128K system.
So I don't think fragmentation is the difference.
--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com