Lightstreamer .Net Adapter 1.10.0
IMetadataProvider.GetMinSourceFrequency Method

Called by Lightstreamer Kernel through the Remote Server to ask for the minimum ItemEvent frequency from the Data Adapter at which the events for an Item are guaranteed to be delivered to the Clients without loss of information. In case of an incoming ItemEvent frequency greater than this value, Lightstreamer Kernel may prefilter the events. Such prefiltering applies only for Items requested with publishing Mode MERGE or DISTINCT. The frequency set should be greater than the ItemUpdate frequencies allowed to the different Users for that Item. Moreover, because this filtering is made without buffers, the frequency set should be far greater than the ItemUpdate frequencies allowed for that Item for which buffering of event bursts is desired. If an Item is requested with publishing Mode MERGE or DISTINCT and unfiltered dispatching, then specifying any limited source frequency will cause the refusal of the request by the Kernel. This feature is just for ItemEventBuffers protection against Items with a very fast flow on the Data Adapter and a very slow flow allowed to the Clients. If this is the case, but just a few Clients need a fast or unfiltered flow for the same MERGE or DISTINCT Item, the use of two differently named Items that receive the same flow from the Data Adapter is suggested. 

This method runs in the Server thread pool specific for the Data Adapter that supplies the involved items, if defined. 


double GetMinSourceFrequency(string item);
double GetMinSourceFrequency(string item);
Visual Basic
Function GetMinSourceFrequency(item As string) As double
string item 
An Item Name. 

The minimum ItemEvent frequency that must be processed without loss of information, in ItemEvents/sec. A zero return value indicates that incoming ItemEvents must not be prefiltered. If the ItemEvents frequency for the Item is known to be very low, returning zero allows Lightstreamer Kernel to save any prefiltering effort.