SYNOPSIS

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

DESCRIPTION

Note

The following description applies both to Postgres-XC and PostgreSQL if not described explicitly.

This command begins a new transaction block. If the isolation level, read/write mode, or deferrable mode is specified, the new transaction has those characteristics, as if SET TRANSACTION (SET_TRANSACTION(7)) was executed. This is the same as the BEGIN(7) command.

PARAMETERS

Refer to SET TRANSACTION (SET_TRANSACTION(7)) for information on the meaning of the parameters to this statement.

COMPATIBILITY

In the standard, it is not necessary to issue START TRANSACTION to start a transaction block: any SQL command implicitly begins a block. Postgres-XC's behavior can be seen as implicitly issuing a COMMIT after each command that does not follow START TRANSACTION (or BEGIN), and it is therefore often called "autocommit". Other relational database systems might offer an autocommit feature as a convenience.

The DEFERRABLEtransaction_mode is a PostgreSQL language extension.

The SQL standard requires commas between successive transaction_modes, but for historical reasons Postgres-XC allows the commas to be omitted.

See also the compatibility section of SET TRANSACTION (SET_TRANSACTION(7)).