Updating index.codec 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.codec from to ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

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

                         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)) {
                        logger.info("updating index.codec from [{}] to [{}]"; InternalEngine.this.codecName; codecName);
                        InternalEngine.this.codecName = codecName;
                        // we want to flush in this case; so the new codec will be reflected right away...
                        requiresFlushing = true;
                    if (failOnMergeFailure != InternalEngine.this.failOnMergeFailure) {


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