On 2025/06/03 19:45, Etsuro Fujita wrote:
On Mon, Jun 2, 2025 at 12:33 PM Michael Paquier <mich...@paquier.xyz> wrote:
On Mon, Jun 02, 2025 at 12:03:50PM +0900, Fujii Masao wrote:
I'm not sure this change should be considered a bug fix,
since the current behavior of postgres_fdw with a local read-only
transaction isn't clearly documented. Some users might see this
as a behavioral change rather than a fix. Anyway if we go with it,
shouldn't we document the change in the v18 release notes?
After going through the thread and the commit, I have to admit that I
was surprised to see this applied on HEAD now that we are in feature
freeze. This is a behavior change. Perhaps this could be done once
v19 happens, still it's rather unclear if the new behavior is better
than the previous one.
No, this is a fix, not a feature, as discussed in the thread; as
mentioned in the commit message, the previous version of postgres_fdw
could cause surprising behaviors that would never happen in normal
cases where a read-only and/or deferrable transaction only
accesses/modifies data on the local server, so this commit fixes those
behaviors.
I agree this could be considered a fix if the new behavior has been
clearly explained in the documentation from before or based on
standards like SQL/MED. But if that's not the case, it seems more
like a behavior change. In that case, I think it should wait for v19
and be applied only after reaching consensus. Some systems might
rely on the previous behavior.
By the way, if a read-only transaction on the local server is meant
to block all write operations on the remote server, this patch alone
might not be sufficient, for example, that read-only transaction can
invoke a login trigger on the remote server and it could still
perform writes.
Regards,
--
Fujii Masao
NTT DATA Japan Corporation
