Elasticsearch Scroll

Elasticsearch Scroll

Opster Team

March 2021


In addition to reading this guide, we recommend you run the Elasticsearch Health Check-Up. It will detect issues and improve your Elasticsearch performance by analyzing your shard sizes, threadpools, memory, snapshots, disk watermarks and more.

The Elasticsearch Check-Up is free and requires no installation.

Run the Elasticsearch check-up to receive recommendations like this:

checklist Run Check-Up
error

The following configuration error was detected on node 123...

error-img

Description

This error can have a severe impact on your system. It's important to understand that it was caused by...

error-img

Recommendation

In order to resolve this issue and prevent it from occurring again, we recommend that you begin by changing the configuration to...

1

X-PUT curl -H "Content-Type: application/json" [customized recommendation]

Overview

In Elasticsearch, the concept of scroll comes into play when you have a large set of search results. Large search results are exhaustive for both the Elasticsearch cluster and the requesting client in terms of memory and processing. The scroll API enables you to take a snapshot of a large number of results from a single search request.

Examples

To perform a scroll search, you need to add the scroll parameter to a search query and specify how long Elasticsearch should keep the search context viable.

GET mydocs-2019/_search?scroll=40s
{
"size": 5000,
"query": {
"match_all": {}
},
"sort": [
 {
 "_doc": {
  "order": "asc"
   }
  }
 ]
}

This query will return a maximum of 5000 hits. If the scroll is idle for more than 40 seconds, it will be deleted. The response will return the first page of the results and a scroll ID. You can use the scroll ID to get additional documents from the scroll. You’ll be able to keep retrieving the documents until you have all of them.

Notes

  • Changes made to documents after the scroll will not show up in your results.
  • When you are done with the scroll, you can delete it manually using the scroll ID.
DELETE _search/scroll/<scroll_id>

Run the Elasticsearch check-up to receive recommendations like this:

checklist Run Check-Up
error

The following configuration error was detected on node 123...

error-img

Description

This error can have a severe impact on your system. It's important to understand that it was caused by...

error-img

Recommendation

In order to resolve this issue and prevent it from occurring again, we recommend that you begin by changing the configuration to...

1

X-PUT curl -H "Content-Type: application/json" [customized recommendation]


Related log errors to this ES concept


Clear SC failed on node
Failed to clear scroll
OnNewScrollContext listener failed
OnFreeScrollContext listener failed
Giving up on search because it failed with a non-retryable exception
Failed to clear scroll
Scroll request failed; scrolling document(s) is stopped
Unable to clear scroll id :
Unable to execute scroll request
Failed to send error response for action clear_sc and request

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