Postgresql – “Unrecognized configuration parameter: qreplace_function” trying to backup a database

There are various ways to set the search_path in PostgreSQL.

To diagnose, log into the same database as the same superuser and check:

SHOW search_path;

If it contains dbms_sql, then check your postgresql.conf, databse and role settings to find where it came from.

Use any editor or for instance grep on in a Linux shell to audit postgresql.conf:

grep 'search_path' /your/path/to/postgresql.conf

To check on database and role settings, use the default command line client psql or a graphical GUI like pgAdmin.

In pgAdmin you just select the object in the object browser to see all settings in the SQL pane.

In psql, use

\drds superuser

to see settings for this role. And

\drds '' db_name

to see settings for the database. Or just

\drds 

to see all settings for all roles and databases.

I hacked the problem by running (as root):

mv /usr/bin/pg_ctl{,-orig}
echo '#!/bin/bash' > /usr/bin/pg_ctl
echo '"$0"-orig "${@/unix_socket_directory/unix_socket_directories}"' >> \
     /usr/bin/pg_ctl
chmod +x /usr/bin/pg_ctl

Run pg_upgrade as intended, then undo the hack:

    mv -f /usr/bin/pg_ctl{-orig,}

The problem is that pg_upgrade executes the program pg_ctrl with arguments that specify files in the old "unix_socket_directory" rather than the new "unix_socket_directories" (note the second is plural). This hack renames the original /usr/bin/pg_ctl to /usr/bin/pg_ctl-orig, and then creates a shell script in its place that simply calls the original pg_ctl program, passing all arguments with any strings "unix_socket_directory" changed to "unix_socket_directories".

In bash, one can change a portion of a string, say from bar to baz in a variable $foo, by using ${foo/bar/baz} (note this does not change the variable, but rather returns the variable's modified contents). Arrays can also be used with ${x/y/z} to retrieve an array with all of its contents replaced, all at once. The variable $@ is an array that contains all arguments passed to the program/script/function, so the new pg_ctl script executes the old one with all arguments changed from the old directory name to the new one.