Prevention of death of a mongodba with a “state” should be: open "

Question

I use mongodb in a multithreaded clojure application using the monger library and one of my producer threads dies with

java.lang.IllegalStateException: state should be: open at com.mongodb.assertions.Assertions.isTrue (Assertions.java:70) com.mongodb.connection.DefaultServer.getConnection (DefaultServer.java:84) com.mongodb.binding.ClusterBinding$ClusterBindingConnectionSource.getConnection (ClusterBinding.java:86) com.mongodb.operation.QueryBatchCursor.getMore (QueryBatchCursor.java:205) com.mongodb.operation.QueryBatchCursor.hasNext (QueryBatchCursor.java:103) com.mongodb.MongoBatchCursorAdapter.hasNext (MongoBatchCursorAdapter.java:46) com.mongodb.DBCursor.hasNext (DBCursor.java:155) clojure.lang.RT$4.invoke (RT.java:512) clojure.lang.LazySeq.sval (LazySeq.java:40) clojure.lang.LazySeq.seq (LazySeq.java:49) clojure.lang.RT.seq (RT.java:525) clojure.core$seq__6416.invokeStatic (core.clj:137) clojure.core$map$fn__6875.invoke (core.clj:2719) clojure.lang.LazySeq.sval (LazySeq.java:40) clojure.lang.LazySeq.seq (LazySeq.java:49) clojure.lang.RT.seq (RT.java:525) clojure.core$seq__6416.invokeStatic (core.clj:137) clojure.core$map$fn__6875.invoke (core.clj:2719) clojure.lang.LazySeq.sval (LazySeq.java:40) clojure.lang.LazySeq.seq (LazySeq.java:49) clojure.lang.RT.seq (RT.java:525) clojure.core$seq__6416.invokeStatic (core.clj:137) clojure.core$filter$fn__6902.invoke (core.clj:2782) clojure.lang.LazySeq.sval (LazySeq.java:40) clojure.lang.LazySeq.seq (LazySeq.java:49) clojure.lang.ChunkedCons.chunkedNext (ChunkedCons.java:59) clojure.lang.ChunkedCons.next (ChunkedCons.java:43) clojure.lang.RT.next (RT.java:703) clojure.core$next__6400.invokeStatic (core.clj:64) clojure.core$dorun.invokeStatic (core.clj:3115) clojure.core$doall.invokeStatic (core.clj:3121) clojure.core$doall.invoke (core.clj:3121) myapp.ns1.$somefn.invokeStatic (ns1.clj:93) myapp.ns1.$somefn.invoke (ns1.clj:90) myapp.ns1$anotherfn.invokeStatic (ns1.clj:124) myapp.ns1$anotherfn.invoke (ns1.clj:116) myapp.ns2$doit.invokeStatic (ns2:21) myapp.ns2$doit.invoke (ns2:17) myapp.ns2$producer$fn__11200.invoke (ns2:45) myapp.ns2$producer.invokeStatic (ns2:31) myapp.ns2$producer.invoke (ns2:25) myapp.ns2$_start$fn__11230.invoke (ns2:70) clojure.core$binding_conveyor_fn$fn__6766.invoke (core.clj:2020) clojure.lang.AFn.call (AFn.java:18) java.util.concurrent.FutureTask.run (FutureTask.java:266) java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1142) java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:617) java.lang.Thread.run (Thread.java:745) 

I found several other hits for this problem, and all of them were resolved by removing some call to conn.close() .

I have one connection that I create at startup, and the only place I call close is at shutdown time. The java driver controls threadpool, so I'm not quite sure what kind of connection we are talking about. Does a DbObject return from a query its own dedicated connection, and this connection dies?

I tried to fix this by specifying :socket-keep-alive true and explicitly setting :socket-timeout to 0 (which is the default and means unlimited), but to no avail.

While some use of with-open , which, as I understand it, can cause a problem that I am facing. Secondly, I accidentally tried to remove all reuse of db objects, but this did not affect the work.

Another thought was that with-open might interact poorly with lazy stuff inside, but wrapping everything in a doall to make it impatient also had no effect.

I work against a set of replicas, and I run locally on a subordinate mongodb with ReadPreference/secondary .

Any other ideas as to what might be wrong?

Answer 1

After removing the laziness layers in my application, the exception changed to something like "DB cursor not found." At that moment, it was obvious that it was wrong, and by controlling my own cursor using notimeout , instead of using monger random errors disappeared.