I was looking for clarifications on the rate limiting for historical data requests. In the post describing this, it said whenever you make a new history request, your number of active requests is increased by 1. Every 1/25th of a second (40 milliseconds) this number decreases by one. As long as you don't exceed a rolling average of 50 history requests per second, you will avoid the "too many requests" error. In other words: time your requests such that you do not exceed 50 per second."

Does this mean I can make 50 new historical requests per second, even if the previous ones have not finished? Or do existing historical requests count in this 50 count as well? For example, if I have currently 15 historical data request ongoing, assuming they don't finish soon, am I limited to 50 new historical requests or 35 (50-15) requests in the next second?

Yes.



No. The historical request limits formerly worked this way, but don't anymore. It's just 50 per second, period. It doesn't matter how many are still running.

I should clarify that the 50 per second limit is per login ID. Making multiple connections with the same login ID doesn't let each connection make 50 requests per second. It is 50 total across all connections, unless you have multiple login IDs.

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Sincerely,
Gary Stephen
DTN IQFeed Implementation Support Specialist