shmem examples not working

[latot]

Hi! I'm learning how to do the shared memory, running the actual example it returns an error:

select vec_select();
ERROR:  PgLwLock was not initialized

Seems the examples are also using a older version of pgrx which can't be used with the git one.

Thx!

[usamoi]

Have you added shmem.so to shared_preload_libraries?

[latot]

Hi! no, I don't see nothing like that in the example project. Other projects (out of pgrx) do not request what is wrote here: https://github.com/pgcentralfoundation/pgrx/blob/develop/docs/src/extension/install.md

pgrx seems to mount its own PG right? where is postgres.conf?

I think would be nice add this points to the example and the missing steps :)

[usamoi]

I think would be nice add this points to the example and the missing steps :)

It's documented in https://docs.rs/pgrx/latest/pgrx/macro.pg_shmem_init.html; this step is needed only if PostgreSQL's shared memory api is used.

where is postgres.conf?

You can get it by SHOW config_file;.

[latot]

Hi, thx for the answer! would be nice write that here. https://github.com/pgcentralfoundation/pgrx/tree/develop/pgrx-examples/shmem

I think is better make that things explicit, when we are starting there is a lot of new things and functions to read, write the needed parts to be able to run the examples can improve them a lot to introduce to pgrx.

I forgot SHOW config_file; exists, thx remind me that!

[latot]

could also be nice have in that example a pg config file and in the instructions load it with

cargo pgrx start --postgres-conf custom_conf_file

This would make the example complete because we can know all that is needed to run it and the exceptions to the rule.