Hi Still trying to start KC with millions of sessions in my JDBC store (remote cache): http://lists.jboss.org/pipermail/keycloak-user/2018-November/016393.html So now, and after the patch made by William Burns, no more OOM, see https://issues.jboss.org/browse/ISPN-9752 But then, I got the following exception during startup, see below. Note, there is a TODO in the code: public boolean track(byte[] key, short status, ClassWhiteList whitelist) { int segment = HotRodConstants.hasCompatibility(status) ? segmentConsistentHash.getSegment(dataFormat.keyToObj(key, status, whitelist)) : segmentConsistentHash.getSegment(key); Set<WrappedByteArray> keys = keysPerSegment.get(segment); // TODO: this assertion may fail due to ISPN assert keys != null : "Segment " + segment + " not initialized, tracking key " + Util.toStr(key); boolean result = keys.add(new WrappedByteArray(key)); if (trace) log.trackingSegmentKey(Util.printArray(key), segment, !result); return result; } Do I have a workaround? Thanks --nick 22:35:55,749 WARN [org.infinispan.client.hotrod.impl.iteration.RemoteCloseableIterator] (pool-16-thread-3) Error reaching the server during iteration: org.infinispan.client.hotrod.exceptions.TransportException:: java.lang.NullPointerException at org.infinispan.client.hotrod.impl.Util.rewrap(Util.java:54) at org.infinispan.client.hotrod.impl.Util.await(Util.java:27) at org.infinispan.client.hotrod.impl.iteration.RemoteCloseableIterator.fetch(RemoteCloseableIterator.java:117) at org.infinispan.client.hotrod.impl.iteration.RemoteCloseableIterator.fetch(RemoteCloseableIterator.java:131) at org.infinispan.client.hotrod.impl.iteration.RemoteCloseableIterator.fetch(RemoteCloseableIterator.java:131) at org.infinispan.client.hotrod.impl.iteration.RemoteCloseableIterator.fetch(RemoteCloseableIterator.java:131) at org.infinispan.client.hotrod.impl.iteration.RemoteCloseableIterator.fetch(RemoteCloseableIterator.java:131) at org.infinispan.client.hotrod.impl.iteration.RemoteCloseableIterator.hasNext(RemoteCloseableIterator.java:99) at org.keycloak.models.sessions.infinispan.remotestore.RemoteCacheSessionsLoader.loadSessions(RemoteCacheSessionsLoader.java:108) at org.keycloak.models.sessions.infinispan.remotestore.RemoteCacheSessionsLoader.loadSessions(RemoteCacheSessionsLoader.java:45) at org.keycloak.models.sessions.infinispan.initializer.SessionInitializerWorker$1.run(SessionInitializerWorker.java:71) at org.keycloak.models.utils.KeycloakModelUtils.runJobInTransaction(KeycloakModelUtils.java:228) at org.keycloak.models.sessions.infinispan.initializer.SessionInitializerWorker.call(SessionInitializerWorker.java:67) at org.keycloak.models.sessions.infinispan.initializer.SessionInitializerWorker.call(SessionInitializerWorker.java:34) at org.infinispan.commands.read.DistributedExecuteCommand.invokeAsync(DistributedExecuteCommand.java:99) at org.infinispan.distexec.DefaultExecutorService$LocalDistributedTaskPart.lambda$execute$1(DefaultExecutorService.java:1060) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.NullPointerException at org.infinispan.client.hotrod.impl.iteration.SegmentKeyTracker.track(SegmentKeyTracker.java:50) at org.infinispan.client.hotrod.impl.operations.IterationNextOperation.acceptResponse(IterationNextOperation.java:111) at org.infinispan.client.hotrod.impl.transport.netty.HeaderDecoder.decode(HeaderDecoder.java:144) at org.infinispan.client.hotrod.impl.transport.netty.HintedReplayingDecoder.callDecode(HintedReplayingDecoder.java:98) at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:647) at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:582) at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:499) at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:461) at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) ... 3 more