Unexpected EOF on client connection

It happened to me when ha-proxy, used to load balance the ETL and reporting tools connecting to Vertica, had the default timeout period of a few minutes. For queries running longer than the timeout of the load balancer, the session closed with an Unexpected EOF in Vertica log.

I believe it is the same situation. We are using F5 load balancer. One thing that I did not understand was which file or directory was being referred in the error message which says " No such file or directory".

In most of the case it socket  file

Setting the ResultBufferSize to 0 would help but may cause a small performance hit due to the serialization (This forces the multiple queries to be result set processed serially, eliminating the breakup of the result set into multiple buffers)

To set the connection parameter ResultBufferSize to 0
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in odbc see the DSN Parameters page
in jdbc see the JDBC Connection Properties page
in ado.net see the ADO.Net cConnection Properties page

You can set this param value like below if using a java application:
Connection dbconn = mydataManager.getConnection( "jdbc:vertica://ipaddress:5433/dbname", "dbadmin", "password"); ((VerticaConnection)dbconn).setProperty("ResultBufferSize", "0" );

For GUI client apps you might have to find the client app's connection editing dialog and figure out how to pass it as a property/parameter, e.g. adding "?ResultBufferSize=0" to the JDBC url in the connection dialog something like "jdbc:vertica://hostname:5433/dbname?ResultBufferSize=0"