Databases Reference
In-Depth Information
Adapter considerations
Some of the adapters need to synchronize their access to shared inbound resources
such as files, database tables, and message queues. The JCA adapters that require
this communicate using cluster software called
Coherence
to run in
active-active
mode, meaning that all adapters are active at the same time but they co-ordinate
their activities to avoid conflicts. This is configured by default and is a significant
improvement over the active-passive adapter configurations that were required in
SOA Suite 10
g
.
Metadata repository considerations
The repository is used not just to hold metadata, but also to persist runtime
information such as BPEL process instance state. Hence it is important that this
component is highly available to avoid outages due to database failure. Oracle
Real Application Clusters can be used to provide a highly available database for
the repository. Without the repository, the SOA Suite will not be able to operate so
thought must be given to the availability characteristics of the database it uses.
Database connections
Although of a particular concern to the metadata repository, the number of
database connections needed in a cluster is also relevant to application data sources.
When sizing the database connection pools in the application server, it should be
remembered that every dispatcher thread (invoker, engine, and system) will need
at least one connection to the metadata repository. In addition, each concurrent
request/reply message will require another connection.
When sizing the number of sessions and processes in the database, it is important
to remember to size them based on the sum of the number of connections in the
managed server pools multiplied by the number of managed servers, plus the
number of connections in the connection pools of the Admin server.
