I/O error occured while sending to the backend on JDBC connection

Hello, We have front application error out on regular basis with 'com.vertica.util.PSQLException: An I/O error occurred while sending to the back-end.' Vertica version is 6.0.x / JDBC Version 5.0.14. We use JDBC to make the call to database and I'm trying to understand why this error happening, We don't see corresponding error on the vertica.log as the SQL ran successfully on the db side. For some reason, the connection got closed or error happened with the connection. SQL runs for few seconds ( 1 to 25 seconds). All our connection are routed thru netscalar load balancer and here is the setting. Any thoughts on why I'm hitting this error ? Settings: Type Vserver_Port Setting Current_Value Default_Value application 5433 clienttimeout 3600 180 application 5433 servertimeout 3600 360 vserver 5433 vserverclienttimeout 3600 180


  • Any update on this?
  • Any update on this?
  • I regularly have this error as well, from JDBC, odbc or direct vsql connection, but could not find any reason. Using stingray as a load balancer, with a 10 hour timeout limit.
  • Hi all, For what it's worth: This is something that we periodically see with various load-balancer products. I'm not personally familiar with these particular products; I would suggest contacting them. One important thing to note, Vertica does not currently send any sort of keepalive message. So it can sit idle for an unusually long period of time without any sign of activity, particularly with long-running queries. Some load-balancers are not designed for this, and so have trouble with it. Relatedly, any system that does network-address translation ("NAT"; community users may see this with home routers, for example) will also likely have trouble with this type of connection. Adam
  • Thanks for pointing this out Adam. If you say 'with various load balancer' does that mean that if we follow the way documented in the doc (using the IPVS load balancer package as described at https://my.vertica.com/docs/6.1.x/HTML/index.htm#15246.htm) we would be fine? Thanks,
  • Hi Guillaume, In that case, yes, I would expect you to be fine. (Assuming that the problem is actually with your load balancer, not with some other part of the network; and that you're fully replacing your load balancer with IPVS.) Adam

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