Message-ID: <b9e99ded23e0b40822f028fdf0a34dfb02a4c1c4.camel@cybertec.at>
Subject: Re: Bug in copy
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: me nefcanto <sn.1361@gmail.com>
Cc: Zhang Mingli <zmlpostgres@gmail.com>, pgsql-bugs@lists.postgresql.org
Date: Sun, 09 Feb 2025 17:39:47 +0100
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On Sun, 2025-02-09 at 16:00 +0330, me nefcanto wrote:
> @laurenz if I use `insert into` or the `merge` would I be able to bypass =
records
> with errors? Or would I fail there too? I mean there are lots of ways a r=
ecord
> can be limited. Unique indexes, check constraints, foreign key constraint=
s, etc.
> What happens in those cases?

With INSERT ... ON CONFLICT, you can only handle primar and unique key viol=
ations.
MERGE allows some more freedom, but it also only checks for rows that match=
 existing
rows.

You won't find a command that ignores or handles arbitrary kinds of errors.
You have to figure out what kinds of errors you expect and handle them expl=
icitly
by running queries against the data.

I don't think that a catch-it-all handler that handles all errors would be =
very
useful.  Normally, there are certain errors you want to tolerate, while oth=
ers
should be considered unrecoverable and lead to errors.

Yours,
Laurenz Albe