Illegal state got wrong mapping task type – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 1.7-1.7

Briefly, this error occurs when Elasticsearch encounters an unexpected mapping task type during an index operation. This could be due to a mismatch between the expected and actual task type. To resolve this issue, you can try the following: 1) Check your mapping configuration for any inconsistencies or errors. 2) Ensure that the task type matches the operation you’re trying to perform. 3) Update your Elasticsearch version if it’s outdated, as this could be a bug that’s been fixed in a newer version.

In addition we recommend you run the Elasticsearch Template Optimizer to fix problems in your data modeling.

It will analyze your templates to detect issues and improve search performance, reduce indexing bottlenecks and optimize storage utilization. The Template Optimizer is free and requires no installation.

Log Context

Log “illegal state; got wrong mapping task type [{}]” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                     dirty = true;
                } catch (Throwable t) {
                    logger.warn("[{}] failed to update-mapping in cluster state; type [{}]"; index; updateTask.type);
            } else {
                logger.warn("illegal state; got wrong mapping task type [{}]"; task);
        return dirty;