ALTER enums (was Re: [COMMITTERS] pgsql: doc: first draft of Postgres 10 release notes)

Bruce Momjian wrote:
> doc: first draft of Postgres 10 release notes

I noticed that this item

+<!--
+Author: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
+2016-09-05 [15bc038f9] Relax transactional restrictions on ALTER TYPE ... ADD V
+-->
+<para>
+Reduce locking required for adding values to enum types (Andrew Dunstan,
+Tom Lane)
+</para>
+
+<para>
+Previously it was impossible to run <command>ALTER TYPE ... ADD
VALUE</> in a
+transaction block unless the enum type was created in the same block.
+Now, only references to uncommitted enum values from other transactions
+is prohibited.
+</para>

does not really explain this change very clearly. (The release note item
was slightly changed later, but not in the substance.) It says it's
about "locking", but it is certainly not about what we normally call
"locking" in Postgres.

So, firstly I suggest it doesn't belong in the "Locking" section, but
rather it should be under "Utility Commands" instead. Second, I think
it should say "Reduce transactional requirements" rather than "reduce
locking required".

I think there are further changes needed because of commits 175774d2932d
and 01c5de88ff2, but that's not what I'm on about here, though
discussion on that is welcome.

Contrary opinions?

--
Álvaro Herrera https://www.2ndQuadrant.com/
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