@nimesh.jain, yes, if you increase the number of items you can expect the extraction time to increase. Extraction time depends on several parameters:
It is impossible to calculate the time for an extraction, it varies too much. I tried making the same query repeatedly and measuring the extraction time, the variance was high. Experience will give you a feeling for the type of time you can expect.
The obvious rule of thumb is: the more data you request, the longer it will take.
That said, it is more efficient to make one request for many RICs, rather than many requests for few RICs, because of the overhead. See this document for tips on optimizing your requests.
@nimesh.jain, you do not mention if you are using the SOAP or REST API, nor what kind of prices or how many fields you are extracting, but I a not surprised by what you observe, 40-50 seconds is the type of performance you can expect from DSS, which is not a real-time product.
@Christiaan Meihsl this is the case when i try to extract 60 instruments. will the time increase if i try to extract 350-400 instruments through REST API in one go. Also i wanted to know what is the maximum number of instruments i can use in on request.