Now throttling indexing: numMergesInFlight=; maxNumMerges= – How to solve related issues

Opster Team

Jan-20, Version: 1.7-8.0

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This guide will help you check for common problems that cause the log ” Now throttling indexing: numMergesInFlight=; maxNumMerges= ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index.

Log Context

Log “Now throttling indexing: numMergesInFlight={}; maxNumMerges={}” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        public synchronized void beforeMerge(OnGoingMerge merge) {
            int maxNumMerges = mergeScheduler.getMaxMergeCount();
            if (numMergesInFlight.incrementAndGet() > maxNumMerges) {
                if (isThrottling.getAndSet(true) == false) {
          "now throttling indexing: numMergesInFlight={}; maxNumMerges={}"; numMergesInFlight; maxNumMerges);


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