Unexpected null for snapshot upgrade memory requirement for – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.5-8.9

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Briefly, this error occurs when Elasticsearch is unable to calculate the memory requirement for a snapshot upgrade. This could be due to a lack of available resources, a bug in the software, or a misconfiguration. To resolve this issue, you can try increasing the available memory, updating Elasticsearch to the latest version, or checking the configuration settings related to snapshot upgrades. If the problem persists, consider reviewing the logs for more detailed error information.

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This guide will help you check for common problems that cause the log ” unexpected null for snapshot upgrade memory requirement for [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, memory, upgrade, snapshot.

Log Context

Log “unexpected null for snapshot upgrade memory requirement for [{}]” classname is MlMemoryAutoscalingDecider.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                // Memory SHOULD be recently refreshed; so in our current state; we should at least have an idea of the memory used
                .mapToLong(t -> {
                    Long mem = getAnomalyMemoryRequirement(t);
                    if (mem == null) {
                        logger.warn("unexpected null for snapshot upgrade memory requirement for [{}]"; MlTasks.jobId(t.getId()));
                    assert mem != null : "unexpected null for anomaly memory requirement after recent stale check";
                    return mem == null ? 0 : mem;


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