How to fix 2D000: invalid_transaction_termination in PostgreSQL

First, verify that you're actually inside a transaction when trying to COMMIT or ROLLBACK. In PostgreSQL, you need explicit BEGIN statements:

-- This will work:
BEGIN;
INSERT INTO users (name) VALUES ('test');
COMMIT;

-- This will fail with 2D000:
INSERT INTO users (name) VALUES ('test');
COMMIT; -- No BEGIN statement

Check your application code or SQL scripts to ensure every COMMIT/ROLLBACK has a corresponding BEGIN.

PostgreSQL functions (created with CREATE FUNCTION) are atomic by default and cannot contain COMMIT or ROLLBACK. Use CREATE PROCEDURE for code that needs transaction control:

-- This function will cause 2D000 error:
CREATE FUNCTION bad_function() RETURNS void AS $$
BEGIN
  INSERT INTO logs (message) VALUES ('test');
  COMMIT; -- NOT ALLOWED in functions
END;
$$ LANGUAGE plpgsql;

-- Use a procedure instead:
CREATE PROCEDURE good_procedure() AS $$
BEGIN
  INSERT INTO logs (message) VALUES ('test');
  COMMIT; -- ALLOWED in procedures
END;
$$ LANGUAGE plpgsql;

Convert functions to procedures if they need transaction control.

If you need a procedure to commit independently of the calling transaction, use autonomous transactions (available in PostgreSQL 11+):

CREATE PROCEDURE log_error(error_msg text)
LANGUAGE plpgsql
AS $$
DECLARE
  PRAGMA AUTONOMOUS_TRANSACTION;
BEGIN
  INSERT INTO error_logs (message, logged_at) 
  VALUES (error_msg, NOW());
  COMMIT;
END;
$$;

The AUTONOMOUS_TRANSACTION pragma allows the procedure to commit without affecting the main transaction.

Many application frameworks (Django, Rails, Hibernate) manage transactions automatically. The 2D000 error can occur when:
1. Manual SQL with COMMIT/ROLLBACK interferes with framework transaction management
2. Nested @Transactional annotations or decorators
3. Framework attempting to commit after application already committed

Review your framework's transaction documentation and ensure you're not mixing manual transaction control with framework-managed transactions.

For nested transaction scenarios, use savepoints instead of attempting multiple COMMITs:

BEGIN;
INSERT INTO orders (customer_id) VALUES (1);
SAVEPOINT sp1;

-- Nested work that might need rollback
INSERT INTO order_items (order_id, product_id) VALUES (currval('orders_id_seq'), 100);
-- If something goes wrong:
ROLLBACK TO SAVEPOINT sp1;
-- Or continue:
RELEASE SAVEPOINT sp1;

COMMIT; -- Only one COMMIT at the end

Savepoints allow partial rollback without ending the main transaction.

Certain transaction isolation levels and configurations can affect transaction termination. Check your session settings:

SHOW transaction_isolation;
SHOW default_transaction_isolation;
SHOW transaction_read_only;

Read-only transactions cannot have COMMIT statements that modify data. Also ensure you're not in a subtransaction context where COMMIT/ROLLBACK would be invalid.