Message-ID: <ebf6ce77-b180-4d6b-8eab-71f641499ddf@postgrespro.ru>
Date: Wed, 16 Apr 2025 21:31:59 +0700
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Subject: Re: Add Pipelining support in psql
To: Michael Paquier <michael@paquier.xyz>,
 Daniel Verite <daniel@manitou-mail.org>
Cc: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com>,
 Jelte Fennema-Nio <postgres@jeltef.nl>,
 PostgreSQL Hackers <pgsql-hackers@postgresql.org>
References: 
 <CAO6_Xqroaof=Gu_NCg4bZfpdgwOjNW9fg753cuuts-FBnv9UGw@mail.gmail.com>
 <a96682c3-9505-456f-b5c7-1b9d1e6303b4@manitou-mail.org>
 <Z8kilUVjYAHko17g@paquier.xyz>
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From: "a.kozhemyakin" <a.kozhemyakin@postgrespro.ru>
In-Reply-To: <Z8kilUVjYAHko17g@paquier.xyz>
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Hello,

After commit 2cce0fe on master

When executing query:
psql postgres <<EOF
CREATE TABLE psql_pipeline();
\startpipeline
COPY psql_pipeline FROM STDIN;
SELECT 'val1';
\syncpipeline
\getresults
EOF


ERROR:  unexpected message type 0x50 during COPY from stdin
CONTEXT:  COPY psql_pipeline, line 1
Pipeline aborted, command did not run
psql: common.c:1510: discardAbortedPipelineResults: Assertion `res == 
((void *)0) || result_status == PGRES_PIPELINE_ABORTED' failed.
Aborted (core dumped)


The psql crashes with the stack trace:
(gdb) bt
#0  __pthread_kill_implementation (no_tid=0, signo=6, 
threadid=<optimized out>) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=6, threadid=<optimized out>) at 
./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=<optimized out>, signo=signo@entry=6) 
at ./nptl/pthread_kill.c:89
#3  0x0000760edd24527e in __GI_raise (sig=sig@entry=6) at 
../sysdeps/posix/raise.c:26
#4  0x0000760edd2288ff in __GI_abort () at ./stdlib/abort.c:79
#5  0x0000760edd22881b in __assert_fail_base (fmt=0x760edd3d01e8 
"%s%s%s:%u: %s%sAssertion `%s' failed.\n%n",
     assertion=assertion@entry=0x5ba46ab79850 "res == ((void *)0) || 
result_status == PGRES_PIPELINE_ABORTED", file=file@entry=0x5ba46ab6fcad 
"common.c",
     line=line@entry=1510, function=function@entry=0x5ba46ab9c780 
<__PRETTY_FUNCTION__.3> "discardAbortedPipelineResults") at 
./assert/assert.c:96
#6  0x0000760edd23b517 in __assert_fail 
(assertion=assertion@entry=0x5ba46ab79850 "res == ((void *)0) || 
result_status == PGRES_PIPELINE_ABORTED",
     file=file@entry=0x5ba46ab6fcad "common.c", line=line@entry=1510,
     function=function@entry=0x5ba46ab9c780 <__PRETTY_FUNCTION__.3> 
"discardAbortedPipelineResults") at ./assert/assert.c:105
#7  0x00005ba46ab2bd40 in discardAbortedPipelineResults () at common.c:1510
#8  ExecQueryAndProcessResults (query=query@entry=0x5ba4a2ec1e10 "SELECT 
'val1';", elapsed_msec=elapsed_msec@entry=0x7ffeb07262a8,
     svpt_gone_p=svpt_gone_p@entry=0x7ffeb07262a7, 
is_watch=is_watch@entry=false, min_rows=min_rows@entry=0, 
opt=opt@entry=0x0, printQueryFout=0x0)
     at common.c:1811
#9  0x00005ba46ab2983f in SendQuery (query=0x5ba4a2ec1e10 "SELECT 
'val1';") at common.c:1212
#10 0x00005ba46ab3f66a in MainLoop (source=source@entry=0x760edd4038e0 
<_IO_2_1_stdin_>) at mainloop.c:515
#11 0x00005ba46ab23f2a in process_file (filename=0x0, 
use_relative_path=use_relative_path@entry=false) at command.c:4870
#12 0x00005ba46ab1e9d9 in main (argc=<optimized out>, 
argv=0x7ffeb07269d8) at startup.c:420


06.03.2025 11:20, Michael Paquier пишет:
> On Wed, Mar 05, 2025 at 03:25:12PM +0100, Daniel Verite wrote:
>> 	Anthonin Bonnefoy wrote:
>>> I do see the idea to make it easier to convert existing scripts into
>>> using pipelining. The main focus of the initial implementation was
>>> more on protocol regression tests with psql, so that's not necessarily
>>> something I had in mind.
>> Understood. Yet pipelining can accelerate considerably certain scripts
>> when client-server latency is an issue. We should expect end users to
>> benefit from it too.
> That was not a test case we had in mind originally here, but if it is
> possible to keep the implementation simple while supporting your
> demand, well, let's do it.  If it's not that straight-forward, let's
> use the new meta-command, forbidding \g and \gx based on your
> arguments from upthread.
> --
> Michael