From: Tom Lane <tgl@sss.pgh.pa.us>
To: robb@public.law
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18926: PostgreSQL 17.5 produces malformed binary COPY output (`GPOCYP` instead of `PGCOPY`) across platform
Date: Wed, 14 May 2025 08:57:16 -0400
Message-ID: <7389.1747227436@sss.pgh.pa.us> (raw)
In-Reply-To: <18926-f08e7be3ec3647f9@postgresql.org>
References: <18926-f08e7be3ec3647f9@postgresql.org>
PG Bug reporting form <noreply@postgresql.org> writes:
> I'm encountering a bug in PostgreSQL 17.5 where a `COPY ... TO STDOUT WITH
> (FORMAT binary)` operation produces malformed output: the file begins with
> `GPOCYP` instead of the expected `PGCOPY`. This behavior occurs consistently
> across environments, including:
Works as expected for me, on macOS and RHEL8:
$ psql -q -f mini_test.sql >output.bin
$ hexdump -C output.bin | head
00000000 50 47 43 4f 50 59 0a ff 0d 0a 00 00 00 00 00 00 |PGCOPY..........|
00000010 00 00 00 00 01 00 00 00 04 00 00 00 01 ff ff |...............|
0000001f
I think your version of hexdump is regarding the input as 2-byte LSB-first
integers. (Maybe you replaced it with some "helpful" alias?)
You might try double-checking the file with some other tool, eg od:
$ od -c output.bin | head
0000000 P G C O P Y \n 377 \r \n \0 \0 \0 \0 \0 \0
0000020 \0 \0 \0 \0 001 \0 \0 \0 004 \0 \0 \0 001 377 377
0000037
regards, tom lane
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To: pgsql-bugs@postgresql.org
Cc: tgl@sss.pgh.pa.us, robb@public.law, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18926: PostgreSQL 17.5 produces malformed binary COPY output (`GPOCYP` instead of `PGCOPY`) across platform
In-Reply-To: <7389.1747227436@sss.pgh.pa.us>
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