Connection to "host" was leaked. Did you forget to close a response body?

[markschiffner]

We are using the marklogic nifi connector 2.0.0 on Nifi 2.6 calling the ExecuteScriptMarkLogic. We are upgrading from Nifi 1.x to 2.x. We are getting thousands/ten of thousands of the following connection warning message and trying to determine if we have a configuration issue or if there is an issue with the plugin closing the connections.

/opt/nifi/nifi-current/logs/nifi-app.log:291090:2026-05-07 12:05:00,797 WARN [OkHttp ConnectionPool] okhttp3.OkHttpClient A connection to http://mldb-z1-01.core.busops.usmc.mil:8010/ was leaked. Did you forget to close a response body?
/opt/nifi/nifi-current/logs/nifi-app.log-291091-java.lang.Throwable: response.body().close()
/opt/nifi/nifi-current/logs/nifi-app.log-291092- at okhttp3.internal.platform.Platform.getStackTraceForCloseable(Platform.kt:145)
/opt/nifi/nifi-current/logs/nifi-app.log-291093- at okhttp3.internal.connection.RealCall.callStart(RealCall.kt:170)
/opt/nifi/nifi-current/logs/nifi-app.log-291094- at okhttp3.internal.connection.RealCall.execute(RealCall.kt:151)
/opt/nifi/nifi-current/logs/nifi-app.log-291095- at com.marklogic.client.impl.OkHttpServices.sendRequestOnce(OkHttpServices.java:493)
/opt/nifi/nifi-current/logs/nifi-app.log-291096- at com.marklogic.client.impl.OkHttpServices.sendRequestOnce(OkHttpServices.java:488)
/opt/nifi/nifi-current/logs/nifi-app.log-291097- at com.marklogic.client.impl.OkHttpServices.doPost(OkHttpServices.java:4079)
/opt/nifi/nifi-current/logs/nifi-app.log-291098- at com.marklogic.client.impl.OkHttpServices.lambda$postIteratedResourceImpl$10(OkHttpServices.java:3832)
/opt/nifi/nifi-current/logs/nifi-app.log-291099- at com.marklogic.client.impl.OkHttpServices.sendRequestWithRetry(OkHttpServices.java:539)
/opt/nifi/nifi-current/logs/nifi-app.log-291100- at com.marklogic.client.impl.OkHttpServices.postIteratedResourceImpl(OkHttpServices.java:3838)
/opt/nifi/nifi-current/logs/nifi-app.log-291101- at com.marklogic.client.impl.OkHttpServices.postEvalInvoke(OkHttpServices.java:3707)
/opt/nifi/nifi-current/logs/nifi-app.log-291102- at com.marklogic.client.impl.ServerEvaluationCallImpl.eval(ServerEvaluationCallImpl.java:152)
/opt/nifi/nifi-current/logs/nifi-app.log-291103- at org.apache.nifi.marklogic.processor.ExecuteScriptMarkLogic.onTrigger(ExecuteScriptMarkLogic.java:243)
/opt/nifi/nifi-current/logs/nifi-app.log-291104- at org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1274)
/opt/nifi/nifi-current/logs/nifi-app.log-291105- at org.apache.nifi.controller.tasks.ConnectableTask.invoke(ConnectableTask.java:229)
/opt/nifi/nifi-current/logs/nifi-app.log-291106- at org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent$1.run(TimerDrivenSchedulingAgent.java:102)
/opt/nifi/nifi-current/logs/nifi-app.log-291107- at org.apache.nifi.engine.FlowEngine.lambda$wrap$1(FlowEngine.java:105)
/opt/nifi/nifi-current/logs/nifi-app.log-291108- at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
/opt/nifi/nifi-current/logs/nifi-app.log-291109- at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:358)
/opt/nifi/nifi-current/logs/nifi-app.log-291110- at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305)

[rjrudin]

Definitely a connection not being closed. Can be ignored, but certainly needs a fix.

[markschiffner]

• Is this fix scheduled and can it be expedited? (Causing outage for our Nifi upgrade)
• Would leveraging the DBCPConnectionPool help with this issue by reusing the connections versus closing?
• If so, is there documentation for leveraging this parameter with the nifi connection plugin?

[rjdew-progress]

We don't currently have a scheduled release. We'll work with product management to get this prioritized.

I don't believe reusing the connections with DBCPConnectionPool would help in this case.

Tracking this issue internally with JIRA issue https://progresssoftware.atlassian.net/browse/MLE-29884

[markschiffner]

@rjdew-progress Ryan, thank you very much. The developer is trying to update and build locally to test adding the connection close that Rob suggested. This upgrade has a lot of visibilty on our program since Nifi 1.x is out of support. Is there any documentation for setup, configuration, and build commands? TIA.

[rjdew-progress]

Apologies for the delayed response. The best place for that information is in the contributing guide.