PostgreSQL Error 0B000: invalid_transaction_initiation

PostgreSQL error 0B000 (invalid_transaction_initiation) occurs when your code attempts to start a transaction in a context where it is not permitted. This typically happens when nesting BEGIN statements inside an already-active transaction block, or trying to issue transaction control commands inside a regular PL/pgSQL function. Understanding this error is key to writing robust, production-grade PostgreSQL applications.

Top 3 Causes

1. Nested BEGIN Statements

PostgreSQL does not support true nested transactions in the standard sense. Calling BEGIN inside an already-open transaction block triggers a warning (or error depending on the client driver).

-- PROBLEMATIC: Nested BEGIN BEGIN ; INSERT INTO orders ( customer_id , amount ) VALUES ( 1 , 100 .…