PostgreSQL cannot begin/end transactions in PL/pgSQL

Question

I am seeking clarification of how to ensure an atomic transaction in a plpgsql function, and where the isolation level is set for this particular change to the database.

Answer 1

START TRANSACTION;
select foo() ;
COMMIT;

"Unfortunately Postgres has no stored procedures, so you always need to manage the transaction in the calling code" – a_horse_with_no_name

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