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Subject: BUG #19494: Error on transaction commit inside pipeline triggers
 psql's Assert
To: pgsql-bugs@lists.postgresql.org
From: PG Bug reporting form <noreply@postgresql.org>
Cc: exclusion@gmail.com
Reply-To: exclusion@gmail.com, pgsql-bugs@lists.postgresql.org
Date: Tue, 26 May 2026 19:00:01 +0000
Message-ID: <19494-97a86d84fee71c47@postgresql.org>
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Archived-At: 
 <https://www.postgresql.org/message-id/19494-97a86d84fee71c47%40postgresql.org>
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The following bug has been logged on the website:

Bug reference:      19494
Logged by:          Alexander Lakhin
Email address:      exclusion@gmail.com
PostgreSQL version: 18.4
Operating system:   Ubuntu 24.04
Description:       =20

The following psql script:
CREATE TABLE t(a INTEGER PRIMARY KEY DEFERRABLE INITIALLY DEFERRED);
\startpipeline
INSERT INTO t VALUES ($1), ($1) RETURNING * \bind 1 \sendpipeline
\endpipeline

results in:
 a
---
 1
 1
(2 rows)

ERROR:  duplicate key value violates unique constraint "t_pkey"
DETAIL:  Key (a)=3D(1) already exists.
psql: common.c:1503: discardAbortedPipelineResults: Assertion
`pset.available_results > 0' failed.

Program terminated with signal SIGABRT, Aborted.
(gdb) bt
#0  __pthread_kill_implementation (threadid=3D281473811984096,
signo=3Dsigno@entry=3D6, no_tid=3Dno_tid@entry=3D0)
    at ./nptl/pthread_kill.c:44
#1  0x0000ffffba60b718 [PAC] in __pthread_kill_internal (threadid=3D<optimi=
zed
out>, signo=3D6) at ./nptl/pthread_kill.c:89
#2  0x0000ffffba5b757c in __GI_raise (sig=3Dsig@entry=3D6) at
../sysdeps/posix/raise.c:26
#3  0x0000ffffba5a1d48 [PAC] in __GI_abort () at ./stdlib/abort.c:77
#4  0x0000ffffba5b05e0 [PAC] in __assert_fail_base (fmt=3D<optimized out>,
assertion=3D<optimized out>,
    file=3D0xaaaac5a317a8 "common.c", line=3D1503, function=3D<optimized ou=
t>) at
./assert/assert.c:118
#5  0x0000aaaac59d3ffc [PAC] in discardAbortedPipelineResults () at
common.c:1503
#6  0x0000aaaac59d4b28 in ExecQueryAndProcessResults (query=3D0xaaaae5929250
"INSERT INTO t VALUES ($1), ($1) RETURNING * ",
    elapsed_msec=3D0xffffe4d657b0, svpt_gone_p=3D0xffffe4d657af, is_watch=
=3Dfalse,
min_rows=3D0, opt=3D0x0, printQueryFout=3D0x0)
    at common.c:1830
#7  0x0000aaaac59d37b0 in SendQuery (query=3D0xaaaae5929250 "INSERT INTO t
VALUES ($1), ($1) RETURNING * ") at common.c:1214
#8  0x0000aaaac59ee4f8 in MainLoop (source=3D0xffffba730870 <_IO_2_1_stdin_=
>)
at mainloop.c:515
#9  0x0000aaaac59cd488 in process_file (filename=3D0x0,
use_relative_path=3Dfalse) at command.c:4977
#10 0x0000aaaac59fbbcc in main (argc=3D10, argv=3D0xffffe4d65f68) at
startup.c:424

Reproduced starting from 41625ab8e (with s/\sendpipeline/\g/ before
17caf6644).