On 2019-Jun-14, Peter J. Holzer wrote:
> There was a discussion about ZFS' COW behaviour and PostgreSQL reusing
> WAL files not being a good combination about a year ago:
> https://www.postgresql.org/message-id/flat/CACukRjO7DJvub8e2AijOayj8BfKK3XXBTwu3KKARiTr67M3E3w%40mail.gmail.com
>
> Maybe you have the same problem?
Note that Joyent ended up proposing patches to fix their performance
problem (and got them committed). Maybe it would be useful for Tiemen
to try that code? (That commit cherry-picks cleanly on REL_11_STABLE.)
commit 475861b2615dd63ae8431d811749a6f9a15bbfd6
Author: Thomas Munro <tmunro@postgresql.org>
AuthorDate: Tue Apr 2 14:37:14 2019 +1300
CommitDate: Tue Apr 2 14:37:14 2019 +1300
Add wal_recycle and wal_init_zero GUCs.
On at least ZFS, it can be beneficial to create new WAL files every
time and not to bother zero-filling them. Since it's not clear which
other filesystems might benefit from one or both of those things,
add individual GUCs to control those two behaviors independently and
make only very general statements in the docs.
Author: Jerry Jelinek, with some adjustments by Thomas Munro
Reviewed-by: Alvaro Herrera, Andres Freund, Tomas Vondra, Robert Haas and others
Discussion: https://postgr.es/m/CACPQ5Fo00QR7LNAcd1ZjgoBi4y97%2BK760YABs0vQHH5dLdkkMA%40mail.gmail.com
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services