Configuring read-read consistency checking with an assembly tool

Read-read consistency checking only applies to LifeTimeInCache beans whose data is read from another transaction. The product checks that the data is consistent with the data store, and ensures that it is not updated after checking for access intents that are repeatable read (RR).

About this task

For access intents that are read committed (RC), the product checks that the data is consistent at the point of checking; it does not guarantee that the data does not change after the checking. This makes the behavior of the LifeTimeInCache bean the same as beans that are non-LifeTimeInCache.

To perform this checking, you need to configure CMP entity beans with read-read consistency checking. You can do this using an assembly tool. To learn how to complete this task see the topic, Adding bean-level access intent for entity beans 2.x in the assembly tool information center.

Example

Read-read consistency checking only applies to LifeTimeInCache beans whose data is read from another transaction.

Usage scenario

For the access intents that are for repeatable read (RR), this means the product checks that the data is consistent with that in the data store and ensures that no one updates it after the checking. For the Access Intents that are for read committed (RC), this means the product checks that the data is consistent at the point of checking, but it does not guarantee that the data does not change after the checking. This makes the behavior of the LifeTimeInCache bean the same as non-LifeTimeInCache beans.

You have three options for setting consistency checking, as shown in the following scenarios concerning the calculation of interest in "Ann's" bank account. In each case, the data store is shared by this Enterprise JavaBeans (EJB) container managed persistence (CMP) application to calculate the interest and other applications, such as EJB bean managed persistence (BMP) , Java Database Connectivity (JDBC), or legacy applications. Also in each case, the EJB account is configured as a long-lifetime bean.

NONE Read-read checking AT_TRAN_BEGIN Read-read checking AT_TRAN_END



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Last updated: Oct 20, 2010 11:50:58 PM CDT
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