z/OS V1R8 DFSMS Technical Update - IBM Redbooks

In Figure 3-18 we show sample data resulting from the command when a latch was found to
be in contention. This information may be used to identify the holder from the ASID shown,
which may lead to a decision as to whether the holder could be cancelled or whether it would
be necessary to wait.
IGW343I VSAM RLS DIAG STATUS (V.01) 035
|----RESOURCE---| |------ WAITER ------| |--HOLDER---| ELAPSED
TYPE ID JOB NAME ASID TASK ASID TASK TIME
-------- -------- -------- ---- -------- ---- -------- --------
LATCH 7F38B928 SMSVSAM 000A 007CBB58 000A 007CBE88 00:01:07
DESCRIPTION: IDAVTCP - VTCPage Storage Pool
Figure 3-18 Example of information available if RLS latch contention is detected
3.6.3 VSAM RLS DIAG command on pre-z/OS V1R8 systems
There is no support for the VSAM RLS DIAG command on lower level systems, but toleration
maintenance is available to handle the command if it should be issued. In Figure 3-17 on
page 26 we show the toleration maintenance available for systems prior to z/OS V1R8.
Table 3-2 RLS DIAG command toleration maintenance
APAR Description Effect
OA14568 Eliminates confusing message relating to another
internal function
In Figure 3-19 we show the result of issuing the command on a z/OS V1R7 system that has
VSAM RLS enabled and has the PTF for APAR OA14568 installed.
Figure 3-19 D SMS, SMSVSAM,DIAG(CONTENTION) command and output on z/OS V1R7
3.6.4 VSAM RLS performance enhancement
Generates message IGW495I D
SMS,SMSVSAM,DIAG COMMAND FUNCTION
HAS FOUND THE DIAG TABLE HAS NO
ENTRIES
D SMS,SMSVSAM,DIAG(CONTENTION)
IGW495I D SMS,SMSVSAM,DIAG COMMAND FUNCTION HAS FOUND 074
THE DIAG TABLE HAS NO ENTRIES.
z/OS V1R8 introduced a performance enhancement that skips cleaning up the XES lock table
when the SMSVSAM address space is terminated. This function is automatically available,
but can be triggered by using the following command if necessary:
V SMS,SMSVSAM,TERMINATESERVER
If the command is issued on a z/OS V1R8 system, since RLS is a sysplex-wide function, it
affects other systems, and toleration maintenance is required for this.
Chapter 3. DFSMSdfp V1R8 enhancements 27