readProcessed() and MaxReturnDataValues.

[sunny]

Hi, support team

I'm trying to test readProcessed() service MyUAServer.

From Part11, I saw MaxReturnDataValues
"defines the maximum number of values that can be returned by the Server for each HistoricalNode accessed during a request."
It means it will be a limit for readRaw(), readProcessed(), readAtTime() and so on?

I have a C++ source version SDK.In the HistoryManagerBase::readProcessed() function of
/uaserver/uaservercpp/coremodule/historymanagerbase.cpp,
readRaw() is called in the readProcessed() with the maxValues = 5000.

Would you please me tell me
1)why the maxValues is set to 5000?
2)in readProcessed(), the output paramter 'valuesToReturn' size is closely related with 'MaxReturnDataValues'?

Thanks a lot.

sunny

[Support Team]

Hello sunny,

that is just an internal setting for the processing in HistoryManagerBase to stay responsive.
Because the aggregate calculation takes some time the HistoryManagerBase processes the response in pieces of max. 5000 so that the call doesn't timeout while the aggregate calculation is still running.
Like that if the total operation takes too long the server can return a partial result plus a continuation point instead of running into a timeout and discarding the result.