Updating index.index_concurrency from to – How to solve related issues

Updating index.index_concurrency from to – How to solve related issues

Opster Team

Feb-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” Updating index.index_concurrency from to ” to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: index.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up which analyses ES to pinpoint the cause of many errors and provides suitable actionable recommendations how to resolve them (free tool that requires no installation).

Log Context

Log “updating index.index_concurrency from [{}] to [{}]” classname is InternalEngine.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                     !codecName.equals(InternalEngine.this.codecName) ||
                    failOnMergeFailure != InternalEngine.this.failOnMergeFailure ||
                    codecBloomLoad != codecService.isLoadBloomFilter()) {
                try (InternalLock _ = readLock.acquire()) {
                    if (indexConcurrency != InternalEngine.this.indexConcurrency) {
                        logger.info("updating index.index_concurrency from [{}] to [{}]"; InternalEngine.this.indexConcurrency; indexConcurrency);
                        InternalEngine.this.indexConcurrency = indexConcurrency;
                        // we have to flush in this case; since it only applies on a new index writer
                        requiresFlushing = true;
                    if (!codecName.equals(InternalEngine.this.codecName)) {


Run the Check-Up to get a customized report like this:

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