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Search processors

Search processors can be of the following types:

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
filter_query Adds a filtering query that is used to filter requests.
script Adds a script that is run on newly indexed documents.
oversample Increases the search request size parameter, storing the original value in the pipeline state.

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  
personalize_search_ranking Uses Amazon Personalize to rerank search results (requires setting up the Amazon Personalize service).  
retrieval_augmented_generation Used for retrieval-augmented generation (RAG) 0.1.0
rename_field Renames an existing field.  
collapse Deduplicates search hits based on a field value, similarly to collapse in a search request.  
truncate_hits Discards search hits after a specified target count is reached. Can undo the effect of the oversample request processor.  

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
normalization-processor Intercepts the query phase results and normalizes and combines the document scores before passing the documents to the fetch phase.

Viewing available processor types

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

GET /_nodes/search_pipelines

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

Response
{
  "_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 Lucenia, additional processors may be provided by plugins.


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