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From: Jelte Fennema-Nio <postgres@jeltef.nl>
Date: Mon, 8 Dec 2025 22:42:56 +0100
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Subject: Re: Proposal to allow setting cursor options on Portals
To: Dave Cramer <davecramer@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
	Jacob Champion <jacob.champion@enterprisedb.com>
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On Sun, 7 Dec 2025 at 15:38, Dave Cramer <davecramer@gmail.com> wrote:
> My main driver here is to allow the creation of Holdable portals at the protocol level for drivers.

Overall seems like a sensible feature to want. A somewhat random
collection of thoughts:

1. We still have fairly limited experience with protocol options, so
afaik not everyone agrees what we should use a version bump for vs a
protocol extension.
2. I think I like the idea of optional fields that a client can add to
the existing messages. That way "implementing" the new protocol
version is a no-op for clients.
3. I think we should mark optional fields more clearly in the docs
somehow. e.g. Make the docs say <term>Optional Int32</term> and
explain what Optional means in the "Message Data Types" section.
4. I think the server should be strict that it only receives this
optional field for the expected protocol version.
5. Do we really need to add the CURSOR_BINARY flag? Seems confusing
with our other way of indicating binary support, i.e. what does it
mean to say text as the format code but then specify CURSOR_BINARY.
6. What is the benefit of PQsendQueryPreparedWithCursorOptions? I
understand the use case for PQsendBindWithCursorOptions, but not for
PQsendQueryPreparedWithCursorOptions.
7. The server should check that no unknown flags are passed
8. Docs need to be added for the new libpq function(s)

I have one question about your intended usage: I expect you intend to
make using this opt-in for the users of pgjdbc? (i.e. by using some
flag/different method to use this HOLD behaviour)