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reranker-transformers

Introduction​

  • The reranker-transformers module enables reranking search results using sentence transformers models.
  • The reranker-transformers module is run on your own inference container with a pre-trained language transformer model.
Related pages

How to enable​

Weaviate Cloud Services​

The reranker-transformers module is not available on the WCS.

Weaviate open source​

Add reranker-transformers to the ENABLE_MODULES environment variable.

Below is an example Docker Compose file, which will spin up Weaviate with the reranker-transformers module (as well as text2vec-openai).

It also configures reranker-transformers to use the cross-encoder/ms-marco-MiniLM-L-6-v2 model, with CUDA acceleration disabled.

---
version: '3.4'
services:
  weaviate:
    command:
    - --host
    - 0.0.0.0
    - --port
    - '8080'
    - --scheme
    - http
    image: semitechnologies/weaviate:1.21.4
    ports:
    - 8080:8080
    restart: on-failure:0
    environment:
      RERANKER_INFERENCE_API: 'http://reranker-transformers:8080'
      OPENAI_APIKEY: $OPENAI_APIKEY
      QUERY_DEFAULTS_LIMIT: 25
      AUTHENTICATION_ANONYMOUS_ACCESS_ENABLED: 'true'
      PERSISTENCE_DATA_PATH: "./data"
      DEFAULT_VECTORIZER_MODULE: 'text2vec-openai'
      ENABLE_MODULES: 'text2vec-openai,reranker-transformers'
      CLUSTER_HOSTNAME: 'node1'
  reranker-transformers:
    image: semitechnologies/reranker-transformers:cross-encoder-ms-marco-MiniLM-L-6-v2
    environment:
      ENABLE_CUDA: '0'
...

Configuration​

The reranker-transformers module can be configured for any class in the schema.

Reranker selection​

If there is only one reranker module enabled, you don't need to do anything. The reranker module will be used by default.

Where multiple reranker modules are enabled, you must specify the reranker module to be used for each class. You can do this by adding the desired reranker in the moduleConfig section of the schema, even without any further settings.

Set reranker for a class
{
  "classes": [
    {
      "class": "Document",
      ...,
      "moduleConfig": {
        "reranker-transformers": {},  // This will configure the 'Document' class to use the 'reranker-transformers' module
      }
    }
  ]
}

Model selection​

The reranker-transformers module enables using sentence transformers models as a second stage re-ranking for vector, bm25 and hybrid search results.

With reranker-transformers module, you must set the model using environment variables as shown above.

The reranker-transformers module supports the following models:

  • cross-encoder/ms-marco-MiniLM-L-6-v2
  • cross-encoder/ms-marco-MiniLM-L-2-v2
  • cross-encoder/ms-marco-TinyBERT-L-2-v2

These pre-trained models are open-sourced on Hugging Face. The cross-encoder/ms-marco-MiniLM-L-6-v2 model, for example, provides approximately the same benchmark performance as the largest model (L-12) when evaluated on MS-MARCO (39.01 vs. 39.02).

Usage​

Queries​

More resources​

For additional information, try these sources.

  1. Frequently Asked Questions
  2. Weaviate Community Forum
  3. Knowledge base of old issues
  4. Stackoverflow
  5. Weaviate slack channel