Improving performance by deleting ETO control blocks
With ETO, IMS can dynamically delete control blocks. Dynamically deleting control blocks reduces storage usage and can improve performance.
- No user is signed on, and a checkpoint occurs.
- The session is terminated normally or abnormally by either an MTO command or by an autologoff timeout.
If the node is a 3600/Finance or SLU P terminal, message resynchronization
is necessary. The control blocks are not deleted following warm-session
termination, but will be deleted following a /CHANGE NODE
COLDSESS command. For ISC terminals, the control blocks are
deleted after a cold-session termination. The control blocks remain,
however, after an ISC warm-session termination.
/SET, /TEST MFS,
or /EXCLUSIVE command, and issues the /SIGN
OFF command (or is automatically signed off), IMS deletes the user control blocks if: - No messages are queued to any LTERMs related to this user.
- The user is not in conversation, Fast Path mode, or full-function response mode.
If the preceding conditions exist, dynamically created user control blocks are deleted. If the preceding conditions do not exist, the user control blocks can continue to exist until the conditions exist or until an IMS cold start occurs. After special processing options are reset and if all other criteria for deletion exist, the control blocks are deleted at the next checkpoint.
/CHANGE or
the /ASSIGN commands with the SAVE keyword.
These user control blocks are then retained until the commands are
reentered with the NOSAVE keyword.For terminals or users in full-function response mode, IMS does not delete user control blocks after a terminal logoff or a user signoff if both SRMDEF=LOCAL and RCVYRESP=YES, because in this case the full-function response mode is recoverable.