Databases Reference
In-Depth Information
Non-transactional proxy
This is the default type of proxy and the only type of proxy that existed prior to 11
g
.
In this case, if there is no incoming transaction then the proxy will not execute as part
of a transaction. Any transactional proxies or business services that it invokes will
each execute in their own transaction. This means that the invoked services will not
necessarily be all complete or all roll back together. Some services may succeed and
commit, others may throw an error and rollback.
Transactional proxy
A new feature in OSB 11
g
is the transactional proxy. A transactional proxy will start
a new transaction if one does not exist in the request received. From this point on,
the behavior is the same as the transactional binding case, with all transactional calls
in a flow being part of the same transaction. In this case, the transaction is committed
when the proxy flows have completed.
Comparison to EJB
Although OSB is not built using EJBs, the non-transactional proxy behaves
transactionally in a similar way to EJBs with the transaction semantics of participates.
If a transaction exists, they will participate in it, but they will not create a new
transaction themselves.
The transactional proxy and BPEL processes with the transaction partner link
property of
Required
behave in a similar way to EJBs with the transaction
semantics of
Required
. If a transaction already exists, they will participate
in it; if no transaction exists, they will start a new one.
BPEL processes with a transaction partner link property of
requiresNew
behave in a
similar fashion to EJBs with transaction semantics of
requiresNew
. They will always
start a new transaction rather than participate in any calling transaction.
Clustering
The SOA Suite and OSB both take advantage of the underlying clustering capabilities
of the application server. A cluster can consist of one or more server instances
running either the OSB, the SOA Suite, or
Business Activity Monitoring
(
BAM
).
When running on WebLogic, a domain may have no more than one OSB cluster,
one SOA Suite cluster, and/or one BAM cluster.
