Sybase 12.5.1, User Manual

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Summarization level details
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Historical Server
For example, if the playback session start_time is 3 p.m. and the end_time is 6
p.m., and an input recording session started at 1 p.m. and ended at 9 p.m.,
Historical Server calculates data item values for the hours between 3 p.m. and
6 p.m. It prorates cumulative (session) counts and uses weighted averages for
cumulative percentages and rates if the start and end times specified for
playback do not match the start and end times of the input sessions.
Playback with user-defined intervals
This option plays back data summarized into sample intervals of the specified
length. The parameter value is the sample interval, specified as:
“S”
“M:S”
“H:M:S”
“D H:M:S”
where:
• S is seconds.
• M is minutes.
• H is hours.
• D is days.
All components are numeric and can be one or two digits. Some examples are:
"30" (specifies sample intervals of 30 seconds)
"10:0" (specifies sample intervals of 10 minutes)
"8:30:0" (specifies sample intervals of 8 1/2 hours)
"5 0:0:0" (specifies sample intervals of 5 days)
The first sample interval starts at start_time, and every sample, except possibly
the last one, has the specified length. If the requested playback start or end
times fall in the middle of a sample interval in the original recording session,
Historical Server prorates the recorded data values for the playback
sample.The last sample might be shorter, if necessary, to end at the end_time
specified.
Choose this option to summarize data into any desired granularity. This type of
summary can mediate deviations in activity and is useful for observing trends
over time.