Access intent -- isolation levels and update locks

WebSphere Application Server access intent policies provide a consistent way of defining the isolation level for CMP bean data across the different relational databases that might be used in your environment. Within a deployed application, the combination of an access intent policy concurrency definition and access type signifies the isolation level value that WebSphere Application Server sets on the database connection. This combination also signifies the update lock flag that Application Server passes to the database through a JDBC prepared statement. Within the database, the isolation level that is configured by WebSphere Application Server corresponds to a single setting that can differ across database vendors.

The following matrix shows how access intent policies correspond to different database isolation levels and update lock settings:

Access Intent profile Isolation level Update lock implementation
  DB2 Oracle* Sybase Informix Cloudscape SQL Server  
wsPessimisticUpdate- Weakest LockAtLoad (Default policy for CMP beans) RR RC RR RR RR RR No (*Oracle, Yes)
wsPessimisticUpdate RR RC RR RR RR RR Yes
wsPessimisticRead RR RC RR RR RR RR No
wsOptimisticUpdate RC RC RC RC RC RC No
wsOptimisticRead RC RC RC RC RC RC No
wsPessimisticUpdateNo-Collisions RC RC RC RC RC RC No
wsPessimisticUpdate- Exclusive S S S S S S Yes





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Last updated: Jun 21, 2007 9:56:50 PM CDT    WebSphere Application Server for z/OS, Version 5.0.2
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