"Function unaccent(text) does not exist" in update trigger

Question

I've created a trigger for table x1 to update a column y with the expression to_tsvector(unaccent(x1.col1 || ' ' || x2.col1)). This trigger function throws:

function unaccent(text) does not exist

Why would this function not exist when a trigger is called, but exist when executed manually? I'm using Supabase to manage this database.

Answer 1

The function unaccent() is typically the one installed by the additional module unaccent. See:

• Does PostgreSQL support "accent insensitive" collations?

Additional modules can be installed to any schema. (I like to use a dedicated schema.) See:

• Is it recommended to install extensions into pg_catalog schema?

If so, then the schema must be added to the search_path to allow function calls without schema-qualification like you demonstrate.

The obvious explanation for your observation would be that you call the function in one session with an appropriate search_path, and execute the trigger in another session with a different search_path.

To diagnose, add this line to your PL/pgSQL trigger function just before the command calling unaccent() temporarily (and make sure notices are logged or reported to the client, depending on where you look):

RAISE NOTICE 'Current search_path: %', current_setting('search_path');

The simple & safe fix is to schema-qualify the function name. Like:

my_extension_schema.unaccent(text)

But investigate whether schemas and the search_path are handled properly across your DB cluster ...

• Alb: Thank you! I was not aware of the influence of search_path in this case. I thought that these functions were globally accessible.