Re: Regression test fails when 1) old PG is installed and 2) meson/ninja build is used

Hi,

On 2025-04-11 07:53:07 +0000, Hayato Kuroda (Fujitsu) wrote:
> Dear hackers,
>
> While creating patches for older branches I found the $SUBJECT. I do not have much knowledge
> for meson thus I'm not sure it is intentional.

> Reproducer
> =======
> I could reproduce the failure with steps:
>
> 1. install old PG, e.g., PG16. To your system. .so file must be put on your $$LD_LIBRARY_PATH.
> 2. build newer PG, e.g., master, with meson build system [1].
> 3. run regression test and ERROR would be reported [2].
>
> This issue does not happen when I used autoconf/make build system.
>
> Analysis
> =====
>
> According to the log, the instance could be started but psql could not work correctly:
>
> ```
> ----------------------------------- stdout -----------------------------------
> # executing test in /home/hayato/builddir/testrun/regress/regress group regress test regress
> # initializing database system by copying initdb template
> # using temp instance on port 40047 with PID 949892
> Bail out!# test failed
> ----------------------------------- stderr -----------------------------------
> psql: symbol lookup error: psql: undefined symbol: PQservice
> # command failed: "psql" -X -q -c "CREATE DATABASE \"regression\" ...
>
> (test program exited with status code 2)
> ==============================================================================

I can't reproduce this. For me the psql started by pg_regress is the one in
tmp_install and so is the libpq it links to.

$ killall -STOP psql
$ ps aux|grep psql
andres 3375208 0.0 0.0 28696 9972 pts/5 T Apr10 0:00 psql tpch_10
andres 3597915 1.0 0.0 36036 10120 ? T 09:42 0:00 psql -X -a -q -d regression -v HIDE_TABLEAM=on -v HIDE_TOAST_COMPRESSION=on
andres 3597916 1.0 0.0 36036 10120 ? T 09:42 0:00 psql -X -a -q -d regression -v HIDE_TABLEAM=on -v HIDE_TOAST_COMPRESSION=on
andres 3597918 0.6 0.0 36036 10144 ? T 09:42 0:00 psql -X -a -q -d regression -v HIDE_TABLEAM=on -v HIDE_TOAST_COMPRESSION=on
andres 3597920 0.3 0.0 36036 10104 ? T 09:42 0:00 psql -X -a -q -d regression -v HIDE_TABLEAM=on -v HIDE_TOAST_COMPRESSION=on
andres 3597922 0.6 0.0 36036 10120 ? T 09:42 0:00 psql -X -a -q -d regression -v HIDE_TABLEAM=on -v HIDE_TOAST_COMPRESSION=on
andres 3597955 0.0 0.0 6608 2180 pts/0 S+ 09:42 0:00 grep psql
$ ls -l /proc/3597918/exe
lrwxrwxrwx 1 andres andres 0 Apr 11 09:42 /proc/3597918/exe -> /srv/dev/build/postgres/m-dev-assert/tmp_install/srv/dev/install/postgres/m-dev-assert/bin/psql

$ less /proc/3597918/maps
...
000 103:06 4831894711 /srv/dev/build/postgres/m-dev-assert/tmp_install/srv/dev/install/postgres/m-dev-assert/lib/x86_64-linux-gnu/libpq.so.5.18

And meson-logs/testlog.txt shows that the command is executed with
PATH=/srv/dev/build/postgres/m-dev-assert/tmp_install//srv/dev/install/postgres/m-dev-assert/bin:<other things>
LD_LIBRARY_PATH=/srv/dev/build/postgres/m-dev-assert/tmp_install//srv/dev/install/postgres/m-dev-assert/lib/x86_64-linux-gnu

Can you check whether your meson-logs/testlog.txt shows the appropriate
PATH/LD_LIBRARY_PATH and whether libpq is in the right place?

Greetings,

Andres Freund