Hi Paul,

have you tried to set validation query on the pool? something like SELECT 1
FROM dual

I had a bunch of issues with our databases but after we started using
validation query, all issues with disconnected sessions were gone.

Give it a try if you have not done this yet

On Fri, May 25, 2018 at 2:54 PM, Paul Riddle <[email protected]>
wrote:

> NiFi Team,
>
> We are seeing issues in the DBCPConnectionPool service and ExecuteSQL
> processor where threads are hanging from NiFi consistently.  The first set
> of queries goes through without issue when the processor is initially
> started.  After 5 minutes of inactivity, a second set of queries simply
> hangs.
>
> Netstat on the server (netstat -nputwoc | grep 1521 ) shows that once we
> restart the service,  the connection pool is cleared and the processor
> continues to work as normal as long as there is activity within 5min ( that
> consumes the connection pool) .
>
> After 5 min of inactive period the next attempt to make JDBC connection
> uses the connection from the same old pool . It then appears that that pool
> is not good to consume, and if used, causes threads to hang in NiFi
> (consistently reproducible).
>
> There are no errors in the logs during this occurance, or bulletins within
> NiFi.  The threads hang for over 30 minutes at that point.
>
>
>
> Other than default processor configs:
> The max wait time on the processor is set to 30 seconds
>
>
> Other than default controller service configs:
> database driver- oracle.jdbc.driver.OracleDriver
> max wait time- 500 ms
> Max total connections- 8
>
> Any assistance you can provide is appreciated.
>
> Regards,
> Paul
>

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