Transaction Isolation-opracowanie

Transaction Isolation
When a memcached operation such as get or incr causes a query or DML operation in the
underlying InnoDB table, you can control whether it sees the very latest data written to the table, only
data that has been committed, or other variations of transaction isolation level. You control this feature
through the innodb_api_trx_level [1741] configuration option. The numeric values specified with
this option correspond to the familiar isolation level names such as REPEATABLE READ [1501]. See
the description of the innodb_api_trx_level [1741] option for the full list.
The stricter the isolation level, the more certain you can be that the data you retrieve will not be rolled
back or changed suddenly so that a subsequent query sees a different value. But that strictness comes
with greater locking overhead that can cause waits. For a NoSQL-style application that does not use
long-running transactions, you can typically stay with the default isolation level or switch to a less strict
one.
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