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The following covers available content storage configuration options.


content: boolean|sqlite|duckdb|client|url|custom

Enables content storage. When true, the default storage engine, sqlite will be used to save metadata alongside embeddings vectors.

Client-server connections are supported with either client or a full connection URL. When set to client, the CLIENT_URL environment variable must be set to the full connection URL. See the SQLAlchemy documentation for more information on how to construct connection strings for client-server databases.

Add custom storage engines via setting this parameter to the fully resolvable class string.

Content storage specific settings are set with a corresponding configuration object having the same name as the content storage engine (i.e. duckdb or sqlite). None of these are required and are set to defaults if omitted.


    wal: enable write-ahead logging - allows concurrent read/write operations,
         defaults to false


objects: boolean|image|pickle

Enables object storage. Supports storing binary content alongside embeddings vectors and metadata. Requires content storage to also be enabled.

Object encoding options are:

  • standard: Default encoder when boolean set. Encodes and decodes objects as byte arrays.
  • image: Image encoder. Encodes and decodes objects as image objects.
  • pickle: Pickle encoder. Encodes and decodes objects with the pickle module. Supports arbitrary objects.


functions: list

List of functions with user-defined SQL functions, only used when content is enabled. Each list element must be one of the following:

  • function
  • callable object
  • dict with fields for name, argcount and function

An example can be found here.


    path: sets the path for the query model - this can be any model on the
          Hugging Face Model Hub or a local file path.
    prefix: text prefix to prepend to all inputs
    maxlength: maximum generated sequence length

Query translation model. Translates natural language queries to txtai compatible SQL statements.