Query a registered time series cache for data within a timestamp range, immediately returning any cached data. Missing data is retrieved from the data source in the background. Call repeatedly to obtain additional data as it arrives.
system.db.getSeriesCache(handle, begints, endts, [gapTolerance,] valuecolumns) returns Dataset
|handle||Long||Numeric handle from registerSeriesCache().|
|begints||Date||Query start timestamp. Must not be null.|
|endts||Date||Query end timestamp. Must not be null.|
|gapTolerance||Long||Optional, Milliseconds. Insert a null row when consecutive timestamps are further apart than this tolerance.|
|valuecolumns||String||List of Strings defining the value columns to be delivered.|
If there is a chance you won't call the getSeriesCache() function often enough to keep the handle from expiring, you should wrap a first attempt in a try/except block, where the except clause obtains a fresh handle.
The Dataset returned is actually a supporting subclass: SeriesFragment. It carries additional properties and methods that can describe the progress of the cache query.
See the timeSeriesCache expression function for a description of the underlying cache behavior.