PostgreSQL FATAL: could not access file "pg_stat_statements": No such file or directory

Question

Our postgres database (version 9.4 instaled on Debian) stopted working (it has been working for several month withouth problem). When I try to connect using psql I get:

psql: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?

When I check status it seems ok:

service postgresql status
● postgresql.service - PostgreSQL RDBMS
   Loaded: loaded (/lib/systemd/system/postgresql.service; enabled)
   Active: active (exited) since Mon 2018-11-05 17:04:58 CET; 31s ago
  Process: 1367 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 1367 (code=exited, status=0/SUCCESS)

I tried to restart server

service postgresql restart

and in log file I have got

FATAL:  could not access file "pg_stat_statements": No such file or directory

I have tried to find a solution. Mostly the answers are that there is a problem with pg_stat_statements module. I checked the /etc/postgresql/9.4/main/postgres.conf file but the line was commented:

#shared_preload_libraries = ''          # (change requires restart)

As I know we haven't change any postgres configuration files and we haven't done any upgrade or update recently. Thank you in advance for your help.

Answer 1

I fixed the problem with installing

postgresql11-contrib-11.7-1PGDG.rhel8

pay attention that official (pgdg11 repo) RPM for RHEL8/CentOS/Fedora has version (i.e. 11) in packet name:

postgresql11-contrib

P.S Yum also installed dependencies: perl-Carp-1.42-396.el8.noarch perl-Exporter-5.72-396.el8.noarch perl-libs-4:5.26.3-416.el8

Answer 2

I had ever met with the same problem. But later found the cause is that I was running the psql command "alter system set shared_preload_libraries='pg_stat_statements';", which overwrite the PostgreSQL.auto.conf under the $PGDATA path. And, as a consequence, when restarting the postgesql instance again by issuing the "service postgresql start", the postmaster process will read the parameter "shared_preload_libraries" from the conf file "postgreSQL.auto.conf" under $PGDATA instead of from /etc/postgresql/10/main/postgres.conf. where the parameter = ''. So, please comment out the parameter shared_preload_libraries='pg_stat_statements' in postgresql.auto.conf if you want to solve the issue. Thanks.

Answer 3

At the end I have installed pg_stat_statements and then I was able to start postgresql.

Added to postgres.conf:

shared_preload_libraries = 'pg_stat_statements'
pg_stat_statements.track = all
pg_stat_statements.max = 10000
track_activity_query_size = 2048

Installed package postgresql-contrib-9.4:

apt-get install postgresql-contrib-9.4

Restarted postgresql service:

service postgresql restart