Rescore window rescoreContext getWindowSize is too large – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-6.8

Briefly, this error occurs when the rescore window size in Elasticsearch is set too high. The rescore window is the number of top documents that Elasticsearch will ‘rescore’ to get more accurate results. If the window size is too large, it can consume excessive memory and slow down the search performance. To resolve this issue, you can reduce the rescore window size to a more manageable number. Alternatively, you can increase the heap size of your Elasticsearch nodes, but this should be done cautiously to avoid out-of-memory errors.

This guide will help you check for common problems that cause the log ” Rescore window [” + rescoreContext.getWindowSize() + “] is too large. ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: search.

Log Context

Log “Rescore window [” + rescoreContext.getWindowSize() + “] is too large. ” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 throw new QueryPhaseExecutionException(this; "Cannot use [sort] option in conjunction with [rescore].");
 int maxWindow = indexService.getIndexSettings().getMaxRescoreWindow();
 for (RescoreContext rescoreContext: rescore) {
 if (rescoreContext.getWindowSize() > maxWindow) {
 throw new QueryPhaseExecutionException(this; "Rescore window [" + rescoreContext.getWindowSize() + "] is too large. "
 + "It must be less than [" + maxWindow + "]. This prevents allocating massive heaps for storing the results "
 + "to be rescored. This limit can be set by changing the [" + IndexSettings.MAX_RESCORE_WINDOW_SETTING.getKey()
 + "] index level setting.");  }


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