sqlpostgresqltriggersautocommittransaction-isolation

postgresql trigger: disable auto commit and set isolation level


i'm writing a trigger on database INSTEAD OF INSERT ON a table, that made some operation, then insert data into different related tables. Now i need to disable autocommit and set a different isolation level inside trigger, how can i do?


Solution

  • PostgreSQL doesn't have a setting that disables autocommit except for embedded SQL. If you try to set autocommit off in, say, PSQL, you'll see something like this error.

    sandbox=# set autocommit=off;
    ERROR:  SET AUTOCOMMIT TO OFF is no longer supported
    

    Instead, use BEGIN to start a transaction. In PostgreSQL, you can start a transaction and set the isolation level in a single statement. (Other platforms require multiple statements.) Skeleton syntax for PostgreSQL 9.2 is

    BEGIN [ WORK | TRANSACTION ] [ transaction_mode [, ...] ]
    
    where transaction_mode is one of:
    
        ISOLATION LEVEL { SERIALIZABLE   | REPEATABLE READ | 
                          READ COMMITTED | READ UNCOMMITTED }
        READ WRITE | READ ONLY
        [ NOT ] DEFERRABLE
    

    End the transaction with either COMMIT or ROLLBACK.