Dropping pending state more than pending states – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-7.17

Briefly, this error occurs when there are too many cluster state updates in the queue of the master node in Elasticsearch. This could be due to high load, slow processing, or network issues. To resolve this, you can increase the ‘cluster.max_in_flight_requests’ setting, optimize your indexing strategy to reduce load, or improve the network connectivity between nodes. Also, ensure your master node has sufficient resources to handle the load.

This guide will help you check for common problems that cause the log ” dropping pending state [{}]. more than [{}] pending states. ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: discovery.

Log Context

Log “dropping pending state [{}]. more than [{}] pending states.” classname is PendingClusterStatesQueue.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

    /** Add an incoming; not yet committed cluster state */
    public synchronized void addPending(ClusterState state) {
        pendingStates.add(new ClusterStateContext(state));
        if (pendingStates.size() > maxQueueSize) {
            ClusterStateContext context = pendingStates.remove(0);
            logger.warn("dropping pending state [{}]. more than [{}] pending states."; context; maxQueueSize);
            if (context.committed()) {
                    new ElasticsearchException("too many pending states ([{}] pending)"; maxQueueSize)