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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 fuli list.

The stricter the isolation level, the morę 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.