Isolation levels let you control the degree to which data can be accessed by other users during a transaction. With version 15.0, Replication Server decouples isolation levels and serialization methods for the replicate data server, and enables all isolation levels for replicate data servers that Replication Server supports. In versions earlier than 15.0, Replication Server supported only isolation level 3.
Through the use of custom function strings, Replication Server supports all isolation levels the replicate data servers may use. Support is not limited to the ANSI standard only.
Each isolation level specifies the types of actions that are not permitted while concurrent transactions are processing. Higher levels include the restrictions imposed by lower levels.
0 – ensures that data written by one transaction represents the actual data.
1 – prevents dirty reads and ensures that data written by one transaction represents the actual data.
2 – prevents nonrepeatable reads and dirty reads, and ensures that data written by one transaction represents the actual data.
3 – prevents phantom rows, nonrepeatable reads, and dirty reads, and ensures that data written by one transaction represents the actual data.
The default value is the current transaction isolation level for the target data server.
alter connection to TOKYO_DS.pubs2 set dsi_isolation_level to ‘2’
alter connection to TOKYO_DS.pubs2 set dsi_serialization_method to ’isolation_level_3’
alter connection to TOKYO_DS.pubs2 set dsi_serializaiton_method to ’wait_for_start’
alter connection to TOKYO_DS.pubs2 set dsi_isolation_level to ’3’