On Tue, Jul 23, 2019 at 7:29 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Parallel workers aren't ever allowed to write, in the current
> implementation, so it's not real obvious why they'd have any
> WAL log files open at all.
Parallel workers are not forbidden to write WAL, nor are they
forbidden to modify blocks. They could legally HOT-prune, for example,
though I'm not positive whether they actually do.
The prohibition is at a higher level: they can't create new tuples or
delete existing ones.
--
Robert Haas
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