Journal fileless mode is a mode in which system journal files (recovery journals containing historical information about OpenTP1, user journals containing historical information about UAPs, and statistical journals) are not acquired.

OpenTP1 acquires system journal files which can be used to recover the system or investigate aspects of OpenTP1 operation. However, system journal files do not need to be acquired in the following system configurations.

Examples of systems where system journal file acquisition is unnecessary:

• Systems that use TP1/EE to control transactions
• Systems that do not implement system recovery using the journal service
• Systems that use name service nodes instead of transaction control

Using journal fileless mode for systems of this nature can help free resources for other uses.

To enable journal fileless mode, specify Y for the jnl_fileless_option operand in the system common definition. Environments that use journal fileless mode are said to be running in journal fileless mode.

The OpenTP1 facilities listed in the following table cannot be used in journal fileless mode.

Table 4-14 Facilities unavailable in journal fileless mode

Category	Unavailable facility
Facility	Transaction facility#1
	Transactional linkage using the XA resource service
	Resource managers (such as DAM and TAM) provided by OpenTP1
	Statistical information
	Global archive journal facility
	Automatic unloading facility
Library function	dc_jnl_ujput
	dc_trn_begin
	dc_trn_unchained_commit
	dc_trn_chained_commit
	dc_trn_unchained_rollback
	dc_trn_chained_rollback
	dc_trn_info
	tx_begin
	tx_close
	tx_commit
	tx_info
	tx_open
	tx_rollback
	tx_set_commit_return
	tx_set_transaction_control
	tx_set_transaction_timeout
Operation command	jnlls
	jnlunlfg
	jnlchgfg
	jnlopnfg
	jnlclsfg
	jnlswpfg
	jnlrinf
	jnldelpf
	jnladdpf
	jnlardis
	jnlarls
	jnlatunl
	jnlmkrf
	dcdefchk (logic checks of the journal service definition, system journal service definition, and checkpoint dump service definition)
Other	System recovery by restarting OpenTP1
	atomic_update operand#2 in the user service definition

#1

Because it is not possible to access resource managers via the XA interface, the trnlnkrm command cannot be used to register resource managers with OpenTP1. If a resource manager is registered with OpenTP1 when you start OpenTP1 in journal fileless mode, an error occurs in the startup processing of the monitoring service for the transaction resource manager, and OpenTP1 terminates abnormally.

#2

Because the transaction facility is unavailable, OpenTP1 operates as if the atomic_update operand in the user service definition is set to N, regardless of the actual setting.

The OpenTP1 files and definition files listed in the following table cannot be used in journal fileless mode.

Table 4-15 Files unavailable in journal fileless mode

File type	Unavailable file
OpenTP1 file	System journal file
	Checkpoint dump file
Definition file	Journal service definition file
	System journal service definition file
	Checkpoint dump service definition file