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»Forums Index »Product Support »DTN.IQ Client Software Support »Error "Send Failed to Client" in IQConnectLog.txt
Author Topic: Error "Send Failed to Client" in IQConnectLog.txt (4 messages, Page 1 of 1)

-Interested User-
Posts: 6
Joined: Oct 24, 2020

Posted: Aug 30, 2021 11:44 AM          Msg. 1 of 4

I'm working with QIFeed client on the remote host. When I run a few requests (HIT type) simultaneously, I get in IQConnectLog errors that look like this:
STATUS LookupError 292 7 2021-08-29 17:03:35 Queuing HistoryData to Client: Bytes To Send 7243 : Bytes Sent 872 : Bytes Queued 6371
STATUS LookupError 292 7 2021-08-29 17:03:35 Send Failed to Client: Bytes To Send 13690 : Error 10035 : First 256 bytes of data H_0000000000,2021-06-14 04:09:00,16.300,16.250,16.250,16.250,3015,97,0,

But eventually, I get the same data as with one request without errors (I saved it in files and compared). I suppose that after an error in data sending IQFeed sends it again unless I get all the necessary data, but I'm not sure. Can someone confirm that I will get all data I need when I do parallel requests and see errors like this? Or give me some advice where can I read about it, may be some documentation?

-DTN Evangelist-
Posts: 210
Joined: Jul 3, 2019

Posted: Aug 30, 2021 04:45 PM          Msg. 2 of 4
That is a classic "queueing" situation.

Error 10035 is socket error WSAEWOULDBLOCK, which basically means that the port is blocked when nothing is instructed to block it. This happens whenever the socket receive block is full, and IQFeed cannot send any more data to it. When this happens, IQFeed will hold onto the data and keep trying to re-send it, until it is able to do so, or until there is such a backlog of data that the IQConnect.exe app crashes.

The message "First 256 bytes of data H_0000000000,2021-06-14 04:09:00,16.300,16.250,16.250,16.250,3015,97,0," is what IQFeed was trying to send at the time.

So to answer your question, yes, IQFeed will hold onto any missed data and re-send it as long as it is able to do so. To minimize this, we recommend the following best practices, in no particular oder:

  • Use multi-threading. There should be different threads in your app to receive the data, parse it, and then act on it.

  • Make messages as efficient as possible. Use the SELECT UPDATE FIELDS command on Level 1 to get only the fields you need. Use tSYMBOL instead of wSYMBOL if you don't need bid/ask updates.

  • Having multiple simultaneous connections to IQFeed can help.

  • Increasing the size of the socket receive buffer can help.

Gary Stephen
DTN IQFeed Implementation Support Specialist

-Interested User-
Posts: 6
Joined: Oct 24, 2020

Posted: Aug 31, 2021 07:36 AM          Msg. 3 of 4
Thank you, for your explanation. I'm already using some of these tips and I will think about others.

-Interested User-
Posts: 6
Joined: Oct 24, 2020

Posted: Aug 31, 2021 10:43 AM          Msg. 4 of 4
Can you explain one more thing? In the phrase "Send Failed to Client", does "client" mean my application? Not IQFeed client (IQConnect.exe)?
And where can I find a detailed description of IQConnectLog file?


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