What is for contrib_regression DB in Postgres DBs list?

Question

I ran 2 commands

psql -U postgres

and

postgres=# \l

and then I saw

     List of databases
        Name        | Owner  | Encoding |   Collate   |    Ctype    | Access privileges 
--------------------+--------+----------+-------------+-------------+-------------------
 contrib_regression | spuser | UTF8     | C           | C           | 

I'm interested in purpose of contrib_regression DB. All that I could google a mention of it https://www.postgresql.org/docs/13/contrib-dblink-get-result.html

However, there is no explanation of contrib_regression.

Answer 1

This database is created when you run the regression tests for a PostgreSQL extension that is built using PGXS, the PostgreSQL extension building infrastructure.

The typical procedure is like this:

tar -xzvf extension.tgz
cd extension
make
sudo make install
make installcheck

The last step runs the regression tests and will create the database contrib_regression for that purpose.

You can safely drop that database once the regression tests are done.