How to fix 0Z000: diagnostics_exception in PostgreSQL

-- Check function definition
SELECT pg_get_functiondef('your_function_name'::regproc);

-- Or view all functions in your schema
SELECT
    n.nspname as schema,
    p.proname as function,
    pg_get_functiondef(p.oid) as definition
FROM pg_proc p
JOIN pg_namespace n ON p.pronamespace = n.oid
WHERE n.nspname = 'your_schema'
ORDER BY p.proname;

CREATE OR REPLACE FUNCTION example_function()
RETURNS void AS $$
BEGIN
    -- Your main logic here
    -- ...

EXCEPTION
    WHEN OTHERS THEN
        -- GET STACKED DIAGNOSTICS must be here, not elsewhere
        DECLARE
            v_sqlstate TEXT;
            v_message TEXT;
            v_context TEXT;
        BEGIN
            GET STACKED DIAGNOSTICS
                v_sqlstate = RETURNED_SQLSTATE,
                v_message = MESSAGE_TEXT,
                v_context = PG_EXCEPTION_CONTEXT;

            RAISE NOTICE 'Error: % %', v_sqlstate, v_message;
        END;
END;
$$ LANGUAGE plpgsql;

# On Linux systems, typically:
sudo tail -f /var/log/postgresql/postgresql-*.log

# Or check log location from psql:
psql -c "SHOW log_directory;"
psql -c "SHOW log_filename;"

-- Test basic exception handling
DO $$
BEGIN
    -- Force an error
    PERFORM 1/0;
EXCEPTION
    WHEN division_by_zero THEN
        RAISE NOTICE 'Caught division by zero';
END $$;

-- Test GET DIAGNOSTICS usage
DO $$
DECLARE
    v_count INTEGER;
BEGIN
    INSERT INTO test_table (id) VALUES (1);
    GET DIAGNOSTICS v_count = ROW_COUNT;
    RAISE NOTICE 'Inserted % rows', v_count;
END $$;

SELECT version();