Type              (TST - Runtime)

DESCRIPTION
"Type" displays the location for the storage of a Temporary Storage (TS) queue.


VALUES
The "Type" can display one of three values:
   'M' for main storage (shared memory)
   'A' for auxiliary storage (disk)
   ' ' for default (see Interpretation, below)

INTERPRETATION
Sun MTP can either keep TS queues in main memory or on disk. A TS queue on disk
is maintained as a VSAM file. Hence, Sun MTP can support recoverable TS queues 
on auxiliary storage. When a TS queue is kept in shared memory, Sun MTP simply 
manages the space as blocks of data. A main storage TS queue is not recoverable.

Sun MTP supports the ability to specify the "Type" of the TS queue upon creation.
If this option is not specified to the WRITEQ TS command, the "Type" defaults to
auxiliary storage unless the Sun MTP system was initiated with a '-T M' command 
line option to unikixmain. The '-T' option forces Sun MTP to use either main (M)
or auxiliary storage (A) regardless of what the application program specifies in
the WRITEQ TS command. As long as Sun MTP starts without a '-T' option, the
application program has the opportunity to determine where to store a TS queue.


CONCLUSIONS
Applications that intend to frequently use a particular TS queue should specify 
the "Type" to 'M' (main storage) when a Sun MTP system's response time is slow. 
Because Sun MTP implements an auxiliary "Type" TS queue as a VSAM file, the
storage incurs substantial overhead to access the items on the TS queue. The 
overhead infringes upon the amount of time and CPU available for processing 
transactions. As long as memory availability is high, it is preferable to keep a
TS queue in shared memory. The access speed more than outweighs the memory 
consumption. 

If, however, the TS queue must be recoverable, the TS queue should have be kept
on auxiliary storage. Sun MTP writes all recoverable TS queues to the VSAM file 
TEMPSTGR.  This is a standard recoverable KSDS file.  The recovery mechanism
must be turned on in the Sun MTP VSAM table in order to recover a TS queue.
Sun MTP writes a nonrecoverable auxiliary storage TS queue to the file TEMPSTG.

