SET

SET changes the default isolation level for the current connection.

Synopsis

SET { ISOLATION_LEVEL | ISOLATIONLEVEL | TRANSACTION_ISOLATION }
    { = | TO } { 'READ COMMITTED' | 'SNAPSHOT' }

Description

All three variable spellings target the same connection-local isolation setting. Other connections, including handles for the same embedded engine, retain their own defaults.

Parameters

The value must be a string literal naming READ COMMITTED or SNAPSHOT. Use BEGIN with an explicit isolation level when a per-transaction choice is required.

Result

Success returns an empty command result. New transactions without an explicit level use the updated default.

Transaction behavior

SET changes the default isolation of the current connection only. It does not modify an already active transaction or the defaults of sibling connections.

Errors and limitations

Unknown variable names and isolation values fail. Changing the default while a transaction is active also fails, so the next transaction has an unambiguous connection-local default.

Privileges

SET requires an authenticated session with CONNECT but no object privilege.

Example

SET ISOLATION_LEVEL = 'READ COMMITTED';
BEGIN;
ROLLBACK;