closed connection issue

[adorearun]

I am getting below error intermittently , is there something i am missing

java.sql.SQLException: Closed Connection
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112) ~[ojdbc14-10.2.0.4.0.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146) ~[ojdbc14-10.2.0.4.0.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:208) ~[ojdbc14-10.2.0.4.0.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
	at oracle.jdbc.driver.OracleStatement.ensureOpen(OracleStatement.java:3544) ~[ojdbc14-10.2.0.4.0.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
	at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3351) ~[ojdbc14-10.2.0.4.0.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
	at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3415) ~[ojdbc14-10.2.0.4.0.jar:Oracle JDBC Driver version - "10.2.0.4.0"]
	at org.davidmoten.rx.jdbc.pool.internal.ConnectionNonBlockingMemberPreparedStatement.executeQuery(ConnectionNonBlockingMemberPreparedStatement.java:55) ~[rxjava2-jdbc-0.1-RC35.jar:na]
	at org.davidmoten.rx.jdbc.Select.lambda$create$5(Select.java:72) ~[rxjava2-jdbc-0.1-RC35.jar:na]
	at io.reactivex.internal.operators.flowable.FlowableGenerate.subscribeActual(FlowableGenerate.java:45) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.Flowable.subscribe(Flowable.java:14419) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.Flowable.subscribe(Flowable.java:14365) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.internal.operators.flowable.FlowableScalarXMap$ScalarXMapFlowable.subscribeActual(FlowableScalarXMap.java:160) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.Flowable.subscribe(Flowable.java:14419) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.Flowable.subscribe(Flowable.java:14365) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.internal.operators.flowable.FlowableUsing.subscribeActual(FlowableUsing.java:74) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.Flowable.subscribe(Flowable.java:14419) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.Flowable.subscribe(Flowable.java:14365) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.internal.operators.flowable.FlowableFlatMap$MergeSubscriber.onNext(FlowableFlatMap.java:163) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.internal.subscriptions.DeferredScalarSubscription.complete(DeferredScalarSubscription.java:133) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.internal.operators.single.SingleToFlowable$SingleToFlowableObserver.onSuccess(SingleToFlowable.java:63) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.internal.operators.single.SingleMap$MapSingleObserver.onSuccess(SingleMap.java:64) ~[rxjava-2.1.16.jar:na]
	at org.davidmoten.rx.pool.MemberSingle$Emitter.run(MemberSingle.java:512) ~[rxjava2-pool-0.1-RC35.jar:na]
	at io.reactivex.internal.schedulers.ExecutorScheduler$ExecutorWorker$BooleanRunnable.run(ExecutorScheduler.java:261) ~[rxjava-2.1.16.jar:na]
	at io.reactivex.internal.schedulers.ExecutorScheduler$ExecutorWorker.run(ExecutorScheduler.java:226) ~[rxjava-2.1.16.jar:na]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[na:1.8.0_161]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[na:1.8.0_161]
	at java.lang.Thread.run(Thread.java:748) ~[na:1.8.0_161]

my DB configuration

Class.forName("oracle.jdbc.driver.OracleDriver");
             Connection connection = DriverManager.getConnection(
                     "URL",
                     "user",
                     "pas");
             
            
             NonBlockingConnectionPool pool =
                     Pools.nonBlocking()
                     		
                             .maxPoolSize(Runtime.getRuntime().availableProcessors() * 5)
                             .connectionProvider(ConnectionProvider.from(connection)).healthCheck(DatabaseType.ORACLE).idleTimeBeforeHealthCheck(5, TimeUnit.SECONDS)
                             .createRetryInterval(5, TimeUnit.SECONDS)
                             .build();
             con = connection;
             return Database.from(pool);

[davidmoten]

Thanks for the report, I'll have a think about it.

[davidmoten]

You're using the latest version?

[adorearun]

<dependency>
			<groupId>com.github.davidmoten</groupId>
			<artifactId>rxjava2-jdbc</artifactId>
			<version>0.1-RC35</version>
		</dependency>
		<dependency>
			<groupId>com.oracle</groupId>
			<artifactId>ojdbc14</artifactId>
			<version>10.2.0.4.0</version>
		</dependency>

Also lately i am getting below issue as well, can you please shed some light on this as well?

Exception in thread "pool-1-thread-5" io.reactivex.exceptions.UndeliverableException: java.sql.SQLException: Closed Statement: next
	at io.reactivex.plugins.RxJavaPlugins.onError(RxJavaPlugins.java:367)
	at io.reactivex.internal.operators.flowable.FlowableFlatMap$MergeSubscriber.innerError(FlowableFlatMap.java:607)
	at io.reactivex.internal.operators.flowable.FlowableFlatMap$InnerSubscriber.onError(FlowableFlatMap.java:668)
	at io.reactivex.internal.operators.flowable.FlowableUsing$UsingSubscriber.onError(FlowableUsing.java:125)
	at io.reactivex.internal.operators.flowable.FlowableGenerate$GeneratorSubscription.onError(FlowableGenerate.java:189)
	at io.reactivex.internal.operators.flowable.FlowableGenerate$GeneratorSubscription.request(FlowableGenerate.java:114)
	at io.reactivex.internal.operators.flowable.FlowableUsing$UsingSubscriber.request(FlowableUsing.java:158)
	at io.reactivex.internal.operators.flowable.FlowableFlatMap$InnerSubscriber.onSubscribe(FlowableFlatMap.java:654)
	at io.reactivex.internal.operators.flowable.FlowableUsing$UsingSubscriber.onSubscribe(FlowableUsing.java:99)
	at io.reactivex.internal.operators.flowable.FlowableGenerate.subscribeActual(FlowableGenerate.java:52)
	at io.reactivex.Flowable.subscribe(Flowable.java:14419)
	at io.reactivex.Flowable.subscribe(Flowable.java:14365)
	at io.reactivex.internal.operators.flowable.FlowableScalarXMap$ScalarXMapFlowable.subscribeActual(FlowableScalarXMap.java:160)
	at io.reactivex.Flowable.subscribe(Flowable.java:14419)
	at io.reactivex.Flowable.subscribe(Flowable.java:14365)
	at io.reactivex.internal.operators.flowable.FlowableUsing.subscribeActual(FlowableUsing.java:74)
	at io.reactivex.Flowable.subscribe(Flowable.java:14419)
	at io.reactivex.Flowable.subscribe(Flowable.java:14365)
	at io.reactivex.internal.operators.flowable.FlowableFlatMap$MergeSubscriber.onNext(FlowableFlatMap.java:163)
	at io.reactivex.internal.subscriptions.DeferredScalarSubscription.complete(DeferredScalarSubscription.java:133)
	at io.reactivex.internal.operators.single.SingleToFlowable$SingleToFlowableObserver.onSuccess(SingleToFlowable.java:63)
	at io.reactivex.internal.operators.single.SingleMap$MapSingleObserver.onSuccess(SingleMap.java:64)
	at org.davidmoten.rx.pool.MemberSingle$Emitter.run(MemberSingle.java:512)
	at io.reactivex.internal.schedulers.ExecutorScheduler$ExecutorWorker$BooleanRunnable.run(ExecutorScheduler.java:261)
	at io.reactivex.internal.schedulers.ExecutorScheduler$ExecutorWorker.run(ExecutorScheduler.java:226)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.sql.SQLException: Closed Statement: next
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
	at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146)
	at oracle.jdbc.driver.OracleResultSetImpl.next(OracleResultSetImpl.java:187)
	at org.davidmoten.rx.jdbc.Select.lambda$create$6(Select.java:77)
	at io.reactivex.internal.operators.flowable.FlowableInternalHelper$SimpleBiGenerator.apply(FlowableInternalHelper.java:62)
	at io.reactivex.internal.operators.flowable.FlowableInternalHelper$SimpleBiGenerator.apply(FlowableInternalHelper.java:53)
	at io.reactivex.internal.operators.flowable.FlowableGenerate$GeneratorSubscription.request(FlowableGenerate.java:109)
	... 22 more

[davidmoten]

Ah this is an easy one. You are passing in only one connection so you have a pool of one!

Either use Database.from(url) or the connection provider should look like

.connectionProvider(() -> DriverManager.getConnection(...))

[adorearun]

Thank you , If I use Database.from(url) how should I pass user / pass ?

[davidmoten]

You can put the user and password in the url if you want

[davidmoten]

like this I think: url="jdbc:oracle:thin:username/password@localhost:1521:orcl".

[adorearun]

Thank you David for the prompt response. I have one more question reg pool
Say using the above configuration mentioned I am querying the table of ~26k records in a select query.

1. How many threads will be created?
2. How many connections will be created ?
3. How many records will be fetched in each thread like how split up works?

I need to figure out how my DB is loaded because of this operation? Can you please help me figure this out?

[davidmoten]

The deal is one connection from the pool per query and threading is completely up to you (will happen downstream of the Flowable returned by the select). Sounds like you may need to do a bit of reading on how RxJava Flowables work but I'm happy to clarify where needed.