Sybase 12.5.1, User Manual

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APPENDIX B Specifications for Defining Recording Session Views
User’s Guide
123
To create a non-raw playback view that shows per-process data, the recording
session view and the playback view must include both the Process ID and
Kernel Process ID data items. If playback is
raw
, using only Process ID is
allowed.
Views that include Process ID return rows as follows:
• Recording session views and raw playback views.
These views return a row only for Process IDs that exist at the end of a
sample interval. If a server process terminates in the middle of a sample
interval, a row is not returned for its Process ID.
• Playback views when the session’s summarization_level parameter is
actual
,
entire
, or user-defined intervals.
These views return rows for all server processes included in any of the input
samples. However, since process IDs are not guaranteed to be unique, the
Kernel Process ID data item must also be included to ensure uniqueness of the
key. Otherwise, the view could erroneously summarize two different
processes.
Using the application name
Historical Server accumulates performance data per application by summing
the data for all processes having the same application name. It collects
performance data only for processes that exist as of the end of the sample
interval. See “Using the Process ID” on page 122 for more information.
Empty rows versus no rows in views
When there is no activity to report, some data items cause an empty row (that
is, a row with zero values for result data items) to appear in a view, and other
data items cause the row to be omitted. The rules controlling whether empty
rows appear in a view are:
• Server-level data items always return a row, even when there is no activity
to report.
• Views that contain the key data item Process ID or Application Name only
report on processes that are active as of the end of the sample period.
• Views that contain the key data items Object ID or Stored Procedure ID
omit the row when there is no activity to report during the sample period.