Sybase 12.5.1, User Manual

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CHAPTER 4 Command Reference
User’s Guide
83
For the client to receive a timestamp in this case, there must be a
playback view containing only the data item
Timestamp
or
Timestamp
Datim
. A view containing any other data items returns zero rows.
The playback session’s summarization level affects the number of
empty samples returned during playback:
• if summarization_level is
raw
or
actual
, the entire gap is
represented with one sample. For example, a gap in data between
the hours of 5 p.m. and 9 a.m. would be represented by one
sample.
• if summarization_level is a time interval, such as 1/2 hour
(specified as
"0 00:30:00"
), the gap is represented with a
sample for each time interval. For example, if the time interval is
specified as 1/2 hour, a gap in data between the hours of 5 p.m.
and 9 a.m. would be represented by 32 empty samples.
• if summarization_level is
entire
, gaps are ignored.
hs_shutdown
Description
Shuts down Historical Server.
Syntax hs_shutdown [wait_option]
Parameters
wait_option
specifies whether termination should occur immediately or wait for
active connections to close. Valid values are:
•
no_wait
– causes Historical Server to shut down immediately and
terminates any connections (including those performing playback)
and active recording sessions. The active recording sessions and
playback sessions that are creating new sessions are shut down in
a controlled manner, which prevents corruption of the control file
or any historical data files.
•
wait
(the default) – defers shutdown until all active recording
sessions (including those performing playback) complete and any
other active connections are closed. No new connections are
accepted during this time.
Examples
This example shuts down Historical Server immediately and terminates
any connections and active recording sessions.