Elasticsearch Search

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1 Mins

Elasticsearch Search

Opster Team

October 2021

Average Read Time

1 Mins


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.

To review your Elasticsearch searches and gain insights into important settings affecting your search performance, we recommend you run the Elasticsearch Health Check-Up. It will also detect any configuration issues in your system to help prevent any future incidents in Elasticsearch.

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

Search refers to the searching of documents in an index or multiple indices. The simple search is just a GET API request to the _search endpoint. The search query can either be provided in query string or through a request body.

Examples

When looking for any documents in this index, if search parameters are not provided, every document is a hit and by default 10 hits will be returned.

GET my_documents/_search

A JSON object is returned in response to a search query. A 200 response code means the request was completed successfully.

{
"took" : 1,
"timed_out" : false,
"_shards" : {
"total" : 2,
"successful" : 2,
"failed" : 0
},
"hits" : {
"total" : 2,
"max_score" : 1.0,
"hits" : [
...
]
}
}

Notes and good things to know

  • Distributed search is challenging and every shard of the index needs to be searched for hits, and then those hits are combined into a single sorted list as a final result.
  • There are two phases of search: the query phase and the fetch phase.
  • In the query phase, the query is executed on each shard locally and top hits are returned to the coordinating node. The coordinating node merges the results and creates a global sorted list. 
  • In the fetch phase, the coordinating node brings the actual documents for those hit IDs and returns them to the requesting client.
  • A coordinating node needs enough memory and CPU in order to handle the fetch phase.

Related log errors to this ES concept


Failed to execute input for watch ; reason
Realm is in user-search mode basedn=; search filter=
Giving up on search because it failed with a non-retryable exception
Rollup index not found during rollup search.
OnFreeContext listener failed
OnNewContext listener failed
Clear SC failed on node
Ldapsearch timeout is less than the minimum supported search
Failed to process shard failure to potentially send back shard failure on corruption
Error occurred while reindexing; bulk failures ; search failures
OnQueryPhase listener failed
OnNewScrollContext listener failed

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Run the Check-Up to get a customized report like this:

Analyze your cluster
Synonyms:
Searching