Performance of PI Web Services versus PI to PI Interface in pull configuration

Discussion created by mjarvis Employee on Jun 30, 2011
Latest reply on Jul 6, 2011 by spilon

Hello Team,


I have an external customer that would like data in my PI Server. They have a PI Server, but would like to use PI Web Services to pull the data if possible. I have read in another thread that Stephen Mohr is currently researching performance with PI Web Services, and that  "The number of events should be in the low tens of thousands" This is quite generic, and I'm sure depends on lots of factors, so can we examine my situation?


PI Server 2010 in Seatle, WA. PI Web Services node in the same data center. Client Web Service is in Germany. Ping time is 318ms, windows file sharing yields a throughput of 193 KBytes/sec. I have 1000 float32 tags, each recieving 1 data point/second. 60,000 events/minute. Would it be possible to pull this amount of data using PI Web Services? I can do this with PI to PI and can keep the data up to date within a few seconds - using a push configuration for snapshot data through the Buffer. What overhead is involved with PI Web Services with this type of network communication? I know with the general PI Network Manager we send data in 4KB packets, and there is some overhead using the buffer, is there any compression/addtional overhead with PI Web Services?


I am prepared to test this scenario, but would like some guidance on the approach. My plan is to use the Web Client in Germany to execute an asynchronous call using PIAsynchStatus for each of the 1000 points every minute. I am going to use the  basicHttp binding for the best performance. Are there any other performance tweaks I should consider?


I would like to see if the limit is based on ping time and bandwidth. Even if I cannot send all of the data, I would like to know how much data I can send. I have done similar performance testing with the PI to PI Interface, and would like to see what PI Web Services can handle.




Mike Jarvis