Manual:$wgDBport

Database settings: $wgDBport
Database port. Only used by PostgreSQL.
Introduced in version:	1.7.0 (r15118)
Removed in version:	still in use
Allowed values:	number (or empty string if not set)
Default value:	5432

Other settings: Alphabetical | By Function

Details

Port number used by the database. If left blank, the appropriate port number is used, depending on the DB system being used (as specified by $wgDBtype):

MySQL 

Unused. Set $wgDBserver to "hostname:port" if you need nonstandard port.

Postgres

5432