Connection Transaction Isolation

Use

With this function you can manage the transaction isolation level for the connections created by a particular DataSource object. For more information about transaction isolation, see Locks in the Development Manual.

Activities

This function is available in the Additional tab of the JDBC Connector Service runtime control in the Visual Administrator.

To define the transaction isolation level, set the Default Connection Isolation property. You can choose one of the following options:

DEFAULT - the isolation level of the database in use
Tip
The default isolation level for an Open SQL data source is TRANSACTION_READ_UNCOMMITTED .
TRANSACTION_NONE - this level indicates that the database does not support transactions
TRANSACTION_READ_UNCOMMITTED - this level enables transactions to read data that is being modified by other transactions before they either commit or roll back
TRANSACTION_READ_COMMITTED - this level enables transactions to read data only after the modifying transaction has committed
TRANSACTION_REPEATABLE_READ - this level guarantees that the data the transaction reads is not being modified by another transaction and will not change unless the reading transaction modifies it and commits
TRANSACTION_SERIALIZABLE - this level guarantees maximum data integrity, since only one transaction run as a single serial operation can both read and modify the data at a time. Other transactions can access the data only after the serializable transaction has committed or rolled back.
Note
Running a transaction as a single serial operation is time-consuming. It is therefore recommended that you avoid using the TRANSACTION_SERIALIZABLE isolation level if speed is important for your system.

Tip
The Open SQL for Java framework supports only TRANSACTION_READ_COMMITTED and TRANSACTION_READ_UNCOMMITTED isolation levels for Open SQL data sources.