HP 3000 Manuals HP 3000 Manuals
SET SAMPLING
Enables sampling of the data buffer pool
Scope
SQLMON Only
SQLMON Syntax
SET SA[MPLING] [ON ]
[OFF]
Parameters
ON Specifies that SQLMON samples the data buffer
pool each time a SampleIO subsystem screen is
refreshed. The default value.
OFF Specifies that SQLMON does not sample the data
buffer pool. Improves the performance of SQLMON.
Description
* It is recommended that you issue SET SAMPLING ON, perform
sampling, issue SET SAMPLING OFF, and then access the SampleIO
screens to view the results. You may find it easier to use the
SampleIO screens when sampling is not being performed, because CPU
utilization is smaller.
* SQLMON samples the data buffer pool only when SAMPLING is ON and
you access a SampleIO screen. In that case, SQLMON samples the
data buffer pool 25 times during each refresh cycle.
* The SWAPIN, SWAPOUT, and TOTALIO counters on the SampleIO screens
are incremented to reflect activity during sampling. The counters
are initialized to 0 when you issue SET DBENVIRONMENT. For more
information, see the chapter "Troubleshooting with SQLMON."
* When sampling is ON, the DISPLAYSAMPLES variable determines
whether you see a scale or a screen when samples are collected.
For more information, see the command page for SET DISPLAYSAMPLES.
sequence. First, to turn on sampling, enter
SQLMONITOR SAMPLEIO => SET SAMPLING ON