Kbase P82759: What is the expected behavior of a V 2.0 Fathom Replicated database when the TCP connection for the
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
12/9/2008 |
|
Status: Verified
GOAL:
What is the expected behavior of a V 2.0 Fathom Replicated database when the TCP connection for the Fathom Replication Agent is lost?
FACT(s) (Environment):
All Supported Operating Systems
Fathom Replication
FIX:
Much of the behavior is dependant upon Fathom Replication Version, Replication configuration settings and what state the database is in when the problem occurs.
A general description will be given below, but the Fathom Replication User Guide chapter for Administration and Procedures section "Failure conditions" should be referenced for more detailed coverage.
For Replication V2.0A
When the database is up and running and connection for the Fathom Replication Agent to the target database is lost the AI files will still capture the transactions for updating the target database. The length of time the source stays in replication mode is determined by a number of things such as Fathom Property settings including but not limited to connect-timeout and transition, the amount of AI space available, is there a schema update being done at the time the error occurs, the type of agent connection, etc.
If the agent type is Synchronous Replication and the agents are not connected, the Source database activity will not continue.
When the agent type is Asynchronous and the Fathom Replication server is able to reconnect to the Fathom Replication agent, it again begins processing AI blocks from the RDBMS. When it gets within ten AI blocks of the RDBMS, the Fathom Replication server halts normal database activity and completes the synchronization process. Schema updates are not allowed while the Fathom Replication server is performing synchronization. If schema updates are being performed when failure recovery synchronization begins, source database updates will block until failure recovery completes.
If the Fathom Replication server is not able to reconnect to Fathom Replication agents in the configured connect-timeout period, the Fathom Replication server will terminate and source database activity will continue. When source database activity continues while the Fathom Replication server is not running, be sure that there is enough AI extent space to handle all database activity until the Fathom Replication server is restarted and replication continues.
There is a possibility when failure recovery is being performed and synchronization takes place that the Fathom Replication server might not catch up to the RDBMS. During this time, all target databases are not up to date with the source.
Under normal conditions when the database is being started and Fathom Replication Agent to the target database is lost, the source will can continue to run for
up to 24 hours provided there are enough empty AI files to handle all the
clients activity during this time frame and the value used for the
defer-agent-startup is at the maximum setting of 1440.
For behavior of Replication V 1.0A please reference Solution P82783