query()

This method conducts a vector query.

Invocation

query(expr, output_fields=None, partition_names=None, timeout=None, **kwargs)

Parameters

Parameter	Description	Type	Required
expr	Boolean expression to filter the data.	String	True
partition_names	List of names of the partitions to search on. All partition will be searched if it is left empty.	list[String]	False
output_fields	List of names of fields to output.	list[String]	False
timeout	An optional duration of time in seconds to allow for the RPC. If it is set to None, the client keeps waiting until the server responds or error occurs.	Float	False
kwargs: consistency_level	Consistency level used in the search.	String/Integer	False
kwargs: guarantee_timestamp	Milvus searches on the data view before this timestamp when it is provided. Otherwise, Milvus searches on the most updated data view. This parameter can only be used in the Customized level of consistency.	Integer	False
kwargs: graceful_time	Milvus will use current timestamp minus the graceful_time as the guarantee_timestamp for search. This parameter can only be used in the Bounded level of consistency.	Integer	False
kwargs: travel_timestamp	Timestamp used for Time Travel. Users can specify a timestamp in a search to get results based on a data view at a specified point in time.	Integer	False

Return

A list that contains all results.

Raises

• RpcError: error if gRPC encounter an error.
• ParamError: error if the parameters are invalid.
• DataTypeNotMatchException: error if wrong type of data is passed to server.
• BaseException: error if the return result from server is not ok.

Example

from pymilvus import Collection
collection = Collection("book")      # Get an existing collection.
res = collection.query(
  expr = "book_id in [2,4,6,8]", 
  output_fields = ["book_id", "book_intro"],
  consistency_level="Strong"
)
sorted_res = sorted(res, key=lambda k: k['book_id'])
sorted_res