Re: Random pg_upgrade test failure on drongo

Hello Kuroda-san,

21.11.2023 13:37, Hayato Kuroda (Fujitsu) wrote:
>> This email tells an update. The machine drongo failed the test a week ago [1]
>> and finally got logfiles. PSA files.
> Oh, sorry. I missed to attach files. You can see pg_upgrade_server.log for now.
>

I can easily reproduce this failure on my workstation by running 5 tests
003_logical_slots in parallel inside Windows VM with it's CPU resources
limited to 50%, like so:
VBoxManage controlvm "Windows" cpuexecutioncap 50

set PGCTLTIMEOUT=180
python3 -c "NUMITERATIONS=20;NUMTESTS=5;import os;tsts='';exec('for i in range(1,NUMTESTS+1):
tsts+=f\"pg_upgrade_{i}/003_logical_slots \"'); exec('for i in range(1,NUMITERATIONS+1):print(f\"iteration {i}\");
assert(os.system(f\"meson test --num-processes {NUMTESTS} {tsts}\") == 0)')"
...
iteration 2
ninja: Entering directory `C:\src\postgresql\build'
ninja: no work to do.
1/5 postgresql:pg_upgrade_2 / pg_upgrade_2/003_logical_slots ERROR            60.30s   exit status 25
...
pg_restore: error: could not execute query: ERROR:  could not create file "base/1/2683": File exists
...

I agree with your analysis and would like to propose a PoC fix (see
attached). With this patch applied, 20 iterations succeeded for me.

Best regards,
Alexander