public inbox for [email protected]
help / color / mirror / Atom feedFrom: Steve Lau <[email protected]>
To: [email protected] <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Doc of typmod arg perhaps deserves an update
Date: Fri, 11 Oct 2024 05:33:54 +0000
Message-ID: <[email protected]> (raw)
# Context
I hit the issue described in this thread when building my toy pgvector implementation: https://www.postgresql.org/message-id/162867790903161317q178e11e6ie276d1254c279dd1%40mail.gmail.com, TLDR of the thread is that: When you define a new custom type that needs a type modifier, it is possible (I would say highly possible in my case) that you won’t receive the stored typmod in this type’s input function’s third argument even though it is **stored** in a column’s metadata.
# Documentation of CREATE TYPE perhaps needs more elaboration
The documentation of CREATE TYPE (https://www.postgresql.org/docs/current/sql-createtype.html) says that
“and the third is the typmod of the destination column, if known (-1 will be passed if not).”
Before hitting the issue, I thought -1 will be passed if and only if this type does not have type modifiers, as it is indeed unknown. However, it surprises me that it could also be unknown if your type needs type modifiers and the type modifiers have been successfully stored in the metadata. So I think we could elaborate on this a bit.
Regards, Steve.
view thread (2+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected]
Subject: Re: Doc of typmod arg perhaps deserves an update
In-Reply-To: <[email protected]>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox