On Thu, Mar 18, 2021 at 02:37:43PM -0300, Álvaro Herrera wrote:
> On 2021-Mar-18, Stephen Frost wrote:
> > This is discussed in src/backend/access/transam/README, specifically the
> > section that talks about Skipping WAL for New RelFileNode. Basically,
> > it's the 'wal_level=minimal' optimization which allows WAL to be
> > skipped.
>
> Hmm ... that talks about WAL-skipping *changes*, not WAL-skipping
> *relations*. I thought WAL-skipping meant unlogged relations, but
> I understand now that that's unrelated. In the transam/README, WAL-skip
> means a change in a transaction in a relfilenode that, if rolled back,
> would disappear; and I'm not sure I understand how the code is handling
> the case that a relation is under that condition.
>
> This caught my attention because a comment says "encryption does not
> support WAL-skipped relations", but there's no direct change to the
> definition of RelFileNodeSkippingWAL() to account for that. Perhaps I
> am just overlooking something, since I'm just skimming anyway.
First, thanks for looking at these patches --- I know it isn't easy.
Second, you are right that I equated WAL-skipping relfilenodes with
relations, and this was wrong. I have updated the attached patch to use
the term WAL-skipping "relfilenodes", and checked the rest of the
patches for any incorrect 'skipping' term, but didn't find any.
If "WAL-skipping relfilenodes" is not clear enough, we should probably
rename RelFileNodeSkippingWAL().
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
If only the physical world exists, free will is an illusion.