Thread: Failure with pgbench and --disable-thread-safety in ~v16

Hi all,
(Alvaro in CC.)

While running some tests for 8984480b545d, I have noticed that the TAP
tests of pgbench fail when ~16 is compiled with
--disable-thread-safety:
[16:51:10.467](0.004s) not ok 227 - working \startpipeline with serializable status (got 1 vs expected 0)
[16:51:10.467](0.000s)
[16:51:10.467](0.000s) #   Failed test 'working \startpipeline with serializable status (got 1 vs expected 0)'
#   at t/001_pgbench_with_server.pl line 845.
[16:51:10.467](0.000s) not ok 228 - working \startpipeline with serializable stdout /(?^:type:
.*/001_pgbench_pipeline_serializable)/
[16:51:10.467](0.000s)
[16:51:10.467](0.000s) #   Failed test 'working \startpipeline with serializable stdout /(?^:type:
.*/001_pgbench_pipeline_serializable)/'
#   at t/001_pgbench_with_server.pl line 845.
[16:51:10.467](0.000s) #                   ''
#     doesn't match '(?^:type: .*/001_pgbench_pipeline_serializable)'
[16:51:10.467](0.000s) not ok 229 - working \startpipeline with serializable stdout /(?^:actually processed: (\d+)/\1)/
[16:51:10.467](0.000s)
[16:51:10.467](0.000s) #   Failed test 'working \startpipeline with serializable stdout /(?^:actually processed:
(\d+)/\1)/'
#   at t/001_pgbench_with_server.pl line 845.
[16:51:10.467](0.000s) #                   ''
#     doesn't match '(?^:actually processed: (\d+)/\1)'

This ./configure switch has been removed in 17~, and, while I've not
analyzed the problem in details, I am wondering if this points to an
actual bug with \startpipeline in all branches.

Thanks,
--
Michael

On 2023-Dec-04, Michael Paquier wrote:

> While running some tests for 8984480b545d, I have noticed that the TAP
> tests of pgbench fail when ~16 is compiled with
> --disable-thread-safety:
> [16:51:10.467](0.004s) not ok 227 - working \startpipeline with serializable status (got 1 vs expected 0)
> [16:51:10.467](0.000s) 
> [16:51:10.467](0.000s) #   Failed test 'working \startpipeline with serializable status (got 1 vs expected 0)'
> #   at t/001_pgbench_with_server.pl line 845.
> [16:51:10.467](0.000s) not ok 228 - working \startpipeline with serializable stdout /(?^:type:
.*/001_pgbench_pipeline_serializable)/
> [16:51:10.467](0.000s) 
> [16:51:10.467](0.000s) #   Failed test 'working \startpipeline with serializable stdout /(?^:type:
.*/001_pgbench_pipeline_serializable)/'
> #   at t/001_pgbench_with_server.pl line 845.
> [16:51:10.467](0.000s) #                   ''
> #     doesn't match '(?^:type: .*/001_pgbench_pipeline_serializable)'
> [16:51:10.467](0.000s) not ok 229 - working \startpipeline with serializable stdout /(?^:actually processed:
(\d+)/\1)/
> [16:51:10.467](0.000s) 
> [16:51:10.467](0.000s) #   Failed test 'working \startpipeline with serializable stdout /(?^:actually processed:
(\d+)/\1)/'
> #   at t/001_pgbench_with_server.pl line 845.
> [16:51:10.467](0.000s) #                   ''
> #     doesn't match '(?^:actually processed: (\d+)/\1)'
> 
> This ./configure switch has been removed in 17~, and, while I've not
> analyzed the problem in details, I am wondering if this points to an
> actual bug with \startpipeline in all branches.

Thanks, I'll have a look.  I'm sure I didn't test any of this code with
threading disabled :-)

-- 
Álvaro Herrera               48°01'N 7°57'E  —  https://www.EnterpriseDB.com/
"Saca el libro que tu religión considere como el indicado para encontrar la
oración que traiga paz a tu alma. Luego rebootea el computador
y ve si funciona" (Carlos Duclós)

On 2023-Dec-04, Michael Paquier wrote:

> While running some tests for 8984480b545d, I have noticed that the TAP
> tests of pgbench fail when ~16 is compiled with
> --disable-thread-safety:
> [16:51:10.467](0.004s) not ok 227 - working \startpipeline with serializable status (got 1 vs expected 0)

So the problem is that we do this:

./pgbench -c4 -j2 -t 10 -n -M prepared -f
/home/alvherre/Code/pgsql-build/REL_16_STABLE/src/bin/pgbench/tmp_check/t_001_pgbench_with_server_main_data/001_pgbench_pipeline

and get this error:
pgbench: error: threads are not supported on this platform; use -j1

So, the fix is just to remove the -j2 in the command line.  I'll do that
in a jiffy.  There's no other test that uses -j, except the one
specifically designed to test threads.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
Bob [Floyd] used to say that he was planning to get a Ph.D. by the "green
stamp method," namely by saving envelopes addressed to him as 'Dr. Floyd'.
After collecting 500 such letters, he mused, a university somewhere in
Arizona would probably grant him a degree.              (Don Knuth)

On Mon, Dec 04, 2023 at 12:17:37PM +0100, Alvaro Herrera wrote:
> So, the fix is just to remove the -j2 in the command line.  I'll do that
> in a jiffy.  There's no other test that uses -j, except the one
> specifically designed to test threads.

Thanks for the quick fix.
--
Michael