diff --git a/build.sbt b/build.sbt
index 21bbccb29..b4a171ae9 100644
--- a/build.sbt
+++ b/build.sbt
@@ -253,7 +253,8 @@ lazy val examples =
     .settings(
       publishArtifact := false,
       fork in Test := true,
-      connectInput in Test := true
+      connectInput in Test := true,
+      javaOptions ++= Seq("-Xmx256m", "-XX:+HeapDumpOnOutOfMemoryError"),
     )
     .settings(
       Option(System.getProperty("generateExamples"))
diff --git a/core/src/main/scala/com/criteo/cuttle/ExecutionStreams.scala b/core/src/main/scala/com/criteo/cuttle/ExecutionStreams.scala
index 556f7f955..533d70dda 100644
--- a/core/src/main/scala/com/criteo/cuttle/ExecutionStreams.scala
+++ b/core/src/main/scala/com/criteo/cuttle/ExecutionStreams.scala
@@ -58,9 +58,8 @@ private[cuttle] object ExecutionStreams {
       h.map(_._1)
     }
     maybeWriter.getOrElse {
-      val (w, toClose) = atomic { implicit tx =>
-        val w =
-          new PrintWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(logFile(id), true), "utf8")))
+      val writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(logFile(id), true), "utf8")))
+      val toClose: Seq[PrintWriter] = atomic { implicit tx =>
         val toClose = if (openHandles.size > maxHandles) {
           val toClear = openHandles.toSeq.sortBy(_._2._2).take(openHandles.size - maxHandles + 1).map(_._1)
           toClear.map { id =>
@@ -68,12 +67,14 @@ private[cuttle] object ExecutionStreams {
             openHandles -= id
             writerToClose
           }
-        } else Nil
-        openHandles += (id -> (w -> now))
-        (w, toClose)
+        } else {
+          Nil
+        }
+        openHandles += (id -> (writer -> now))
+        toClose
       }
       toClose.foreach(_.close())
-      w
+      writer
     }
   }
 
diff --git a/core/src/main/scala/com/criteo/cuttle/Executor.scala b/core/src/main/scala/com/criteo/cuttle/Executor.scala
index 55d1ffd07..721469336 100644
--- a/core/src/main/scala/com/criteo/cuttle/Executor.scala
+++ b/core/src/main/scala/com/criteo/cuttle/Executor.scala
@@ -802,16 +802,20 @@ class Executor[S <: Scheduling] private[cuttle] (val platforms: Seq[ExecutionPla
     case object Paused extends NewExecution
     case class Throttled(launchDate: Instant) extends NewExecution
 
+    val index: Map[(Job[S], S#Context),(Execution[S], Future[Completed])] = runningState.single.map {
+      case (execution, future) =>
+        ((execution.job, execution.context), (execution, future))
+    }.toMap
     val existingOrNew
       : Seq[Either[(Execution[S], Future[Completed]), (Job[S], Execution[S], Promise[Completed], NewExecution)]] =
       atomic { implicit txn =>
         if (isShuttingDown()) {
           Seq.empty
         } else
-          all.map {
-            case (job, context) =>
-              val maybeAlreadyRunning: Option[(Execution[S], Future[Completed])] =
-                runningState.find { case (e, _) => e.job == job && e.context == context }
+          all.distinct.zipWithIndex.map {
+            case ((job, context), i) =>
+              if(i > 1000 && i % 1000 == 0) logger.info(s"Submitted ${i}/${all.size} jobs")
+              val maybeAlreadyRunning: Option[(Execution[S], Future[Completed])] = index.get((job, context))
 
               lazy val maybePaused: Option[(Execution[S], Future[Completed])] = pausedState
                 .get(job.id)