Daily retrieval

Daily retrieval is the retrieval of stored data for the given time period based on a resolution of one day, regardless of whether or not the value of the tag(s) has changed. Daily retrieval works similarly to Cyclic retrieval, except that the resolution is always a full local time day (86400000 milliseconds, except across changes between standard and daylight saving time). It works with all types of tags. Daily retrieval produces a virtual rowset, which may or may not correspond to the actual data rows stored on the AVEVA Historian.

In daily retrieval, one row is returned for each cycle. Each cycle represents a day that starts at the local time specified in StartDateTime, and ends when that time next occurs. If the cycle falls on a day that gains or loses an hour due to the start/end of daylight saving time (based on server time), that is accounted for.

If the last cycle ends with less than a full day’s data, either due to ending at a time for which data for the tag is not yet stored, or a time that is less than 24 hours after the previous cycle, that will be reflected in the PercentGood. Time for which data is not available will be treated as “not good.” For example, if only 12 hours of data are available for the cycle, and the day is 24 hours (i.e. not a day with a daylight-saving related time change), the PercentGood will normally be 50, because there is only good data for half of the cycle.

Daily retrieval is only supported with the AnalogSummaryHistory table.