sqdconf start./oracdc/oracdc.cabIt is important to realized that the return code, and message from sqdconf indicating that the start command was executed successfully, does not necessarily mean that the agent is still in started state. It only means that the start command was accepted by the capture agent and that the initial setup necessary to launch a capture thread were successful. These preparation steps involve connecting to Oracle and setting up the necessary environment to start a log mining session as well as opening channels to third party queuing systems such as MQ, if used. These steps would not detect, for instance, a queue-full condition.
The capture agent runs as a daemon, so it does not have a terminal window to emit warnings or errors. Such messages are instead posted in the system log. The daemon name for Oracle capture is sqdlogm NOT sqdconf. If there is a mechanism in place to monitor the system log, it is a good idea to include the monitoring of sqdlogm messages. This will allow you to detect when a capture agent is mounted, started, or stopped - normally or because of an error. It will also contain, for most usual production error conditions, some additional information to help diagnose the problem.
Mar 10 12:11:52 linux sqdlogm[8587]: SQDF018I Mounted capture agent for configuration file ha9
Mar 10 12:12:01 linux sqdlogm[8587]: SQDF024I Started capture agent for configuration file ha9
Mar 10 12:12:36 linux sqdlogm[8587]: SQDF025E The Oracle Database has not been altered for minimal supplemental logging
Mar 10 12:12:36 linux sqdlogm[8587]: SQDF023W The capture thread has been interrupted at Log Point:115292150 for configuration file ha9, rc(0x70018805)