Re: fillfactor and cluster table vs ZFS copy-on-write

On Thu, Apr 16, 2015 at 5:09 AM, Geoff Speicher <gspeicher@umtechx.com> wrote:
> Therefore one might posit that PostgreSQL should be configured to use 100%
> fillfactor and avoid clustering on ZFS. Can anyone comment on this?
>

Even with COW, I can see fillfactor < 100% still have its virtues. For
example, HOT update can avoid adding an extra index item on the index
page if it finds the new item can be inserted in the same heap page.

When you do CLUSTER command, engine will overwrite table into new
files any way, so COW does not affect here.

Regards,
Qingqing