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From: Jelte Fennema-Nio <postgres@jeltef.nl>
Date: Wed, 25 Mar 2026 08:46:35 +0100
Message-ID: 
 <CAGECzQTcWG4Y7nuZ7vjkcDFQKnH9uYd3gf411WBuv-6L8zChvA@mail.gmail.com>
Subject: Re: Proposal to allow setting cursor options on Portals
To: Dave Cramer <davecramer@gmail.com>
Cc: Sami Imseih <samimseih@gmail.com>, Hannu Krosing <hannuk@google.com>,
	Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>,
	Jacob Champion <jacob.champion@enterprisedb.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Heikki Linnakangas <hlinnaka@iki.fi>
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Precedence: bulk

On Tue, 24 Mar 2026 at 11:01, Dave Cramer <davecramer@gmail.com> wrote:
> _pq_.cursor would be fine.

I think that makes sense as a name for the option. I think adding flag
support for SCROLL and NO SCROLL would make sense in that case.

Some notes on the patch (but I didn't look look at the client side
libpq code in detail):

For the protocol definition I'd like a few changes:
1. I'd like the new field in the bind message that you add to be
described as an extension bitmap, not specifically for cursor options,
so that future extensions could add bits too it too.
2. Related to that, I think the used bits should not align with the
internal bits. Having the only valid flag bit be 0x0020 is kinda
weird. Let's just make that 0x0001. We could update the internal ones
to match if desired, but I think it's fine for the protocol bits to
differ from the bits in the postgres server.

Docs still mention CURSOR_OPT_BINARY, but support for that has been
removed from the code afaict (which I think is indeed what should
happen)

There's a bunch of protocol version 3.3 code still around, which
should be removed now that the protocol option is added.

PQsendBindWithCursorOptions and PQsendQueryPreparedWithCursorOptions
should error out if conn->holdable_portal_enabled is false. Right now
it silently skips the cursor options if the connection does not
support the protocol extension.

There should be a libpq function to inspect whether the connection
supports cursor options, so some kind of graceful fallback logic can
be implemented by the application when it's not supported.

libpq docs are missing