Why are missing any tasks ID data in Srvrmgr command List tasks output?

Prior to v8.0, when a task is started, the task info will occupy a 'task slot' in the shared memory of the Siebel server. This task will stay in the shared memory until the task is completed. Once a task is completed, it will stay in the shared memory until all of the 'task slots' are used up. Over time, older completed tasks will be purged from the shared memory to make room for storing new running tasks.

This is the reason why some of the completed tasks will be gone from your 'list task' command once the task is complete.

Starting in v8.0, all these tasks slots are moved from the shared memory into the heap space of each component process. We also introduced a new feature that can persist all the tasks info into a database table: S_SRM_TASK_HIST. This table can be purged periodically by the SvrTblCleanUp component. By moving the tasks slots out of the shared memory, we can accommodate more processes/tasks on the same server, thus improving scalability.

Note that there will be entries in the S_SRM_TASK_HIST table only if task history is enabled and the SvrTaskPersist component is running without any problems on that Siebel server.