How the issue manifests
The following error appears during a database upgrade:
PSQLException: ERROR: language "pltcl" does not exist
Cause
The procedural language PL/Tcl (pltcl) is missing from the database.
👉 This typically occurs after a PostgreSQL update, where:
the main PostgreSQL package is updated
but the corresponding
postgresql-pltclpackage is missing
Resolution
Connect to the database (typically for each company)
Run:
CREATE LANGUAGE pltcl;
If the command fails
You need to install the missing package:
postgresql-pltcl-<version>
(e.g. postgresql-pltcl-13)
Once installed, run the command again.