opensearch-docs-cn/_search-plugins/search-pipelines/search-processors.md

layout	title	nav_order	has_children	parent	grand_parent
default	Search processors	40	true	Search pipelines	Search

Search processors

Search processors can be of the following types:

• Search request processors
• Search response processors
• Search phase results processors

Search request processors

A search request processor intercepts a search request (the query and the metadata passed in the request), performs an operation with or on the search request, and submits the search request to the index.

The following table lists all supported search request processors.

Processor	Description	Earliest available version
filter_query	Adds a filtering query that is used to filter requests.	2.8
neural_query_enricher	Sets a default model for neural search at the index or field level.	2.11
script	Adds a script that is run on newly indexed documents.	2.8
oversample	Increases the search request size parameter, storing the original value in the pipeline state.	2.12

Search response processors

A search response processor intercepts a search response and search request (the query, results, and metadata passed in the request), performs an operation with or on the search response, and returns the search response.

The following table lists all supported search response processors.

Processor	Description	Earliest available version
personalize_search_ranking	Uses Amazon Personalize to rerank search results (requires setting up the Amazon Personalize service).	2.9
retrieval_augmented_generation	Used for retrieval-augmented generation (RAG) in conversational search.	2.10 (generally available in 2.12)
rename_field	Renames an existing field.	2.8
rerank	Reranks search results using a cross-encoder model.	2.12
collapse	Deduplicates search hits based on a field value, similarly to collapse in a search request.	2.12
truncate_hits	Discards search hits after a specified target count is reached. Can undo the effect of the oversample request processor.	2.12

Search phase results processors

A search phase results processor runs between search phases at the coordinating node level. It intercepts the results retrieved from one search phase and transforms them before passing them to the next search phase.

The following table lists all supported search phase results processors.

Processor	Description	Earliest available version
normalization-processor	Intercepts the query phase results and normalizes and combines the document scores before passing the documents to the fetch phase.	2.10

Viewing available processor types

You can use the Nodes Search Pipelines API to view the available processor types:

GET /_nodes/search_pipelines

{% include copy-curl.html %}

The response contains the search_pipelines object that lists the available request and response processors:

Response

{: .text-delta}

{
  "_nodes" : {
    "total" : 1,
    "successful" : 1,
    "failed" : 0
  },
  "cluster_name" : "runTask",
  "nodes" : {
    "36FHvCwHT6Srbm2ZniEPhA" : {
      "name" : "runTask-0",
      "transport_address" : "127.0.0.1:9300",
      "host" : "127.0.0.1",
      "ip" : "127.0.0.1",
      "version" : "3.0.0",
      "build_type" : "tar",
      "build_hash" : "unknown",
      "roles" : [
        "cluster_manager",
        "data",
        "ingest",
        "remote_cluster_client"
      ],
      "attributes" : {
        "testattr" : "test",
        "shard_indexing_pressure_enabled" : "true"
      },
      "search_pipelines" : {
        "request_processors" : [
          {
            "type" : "filter_query"
          },
          {
            "type" : "script"
          }
        ],
        "response_processors" : [
          {
            "type" : "rename_field"
          }
        ]
      }
    }
  }
}

In addition to the processors provided by OpenSearch, additional processors may be provided by plugins. {: .note}