SQL99
SERIALIZABLE is the default isolation level in
SQL99, but it is not the usual default in
PostgreSQL: the factory default setting
is READ COMMITTED.
PostgreSQL
does not provide the isolation levels READ UNCOMMITTED
and REPEATABLE READ. Because of lack of predicate
locking, the SERIALIZABLE level is
not truly serializable. See the User's Guide
for details.
In SQL99 this statement can specify two other
properties of the new transaction: whether the transaction is
read-only and the size of the diagnostics area. Neither of these
concepts are currently supported in
PostgreSQL.
