query()

This method conducts a vector query.

Invocation

query(expr, offset, limit, output_fields=None, partition_names=None, timeout=None)

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
`limit`	Number of nearest records to return. The value of this parameter should be less than 16384.	Integer	False
`offset`	Number of results to skip in the returned set. This parameter is available only when `limit` is specified, and the sum of this value and `limit` should be less than 16384.	Integer	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, it searches the most updated data view. It can be only used in `Customized` level of consistency.	Integer	False
`kwargs`: `graceful_time`	PyMilvus will use current timestamp minus the `graceful_time` as the `guarantee_timestamp` for search. It can be only used in `Bounded` level of consistency.	Integer	False
`kwargs`: `travel_timestamp`	Timestamp that is 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
`kwargs`: `ignore_growing`	Whether to ignore growing segments during similarity searches. The value defaults to `False`, indicating that searches involve growing segments.	Bool	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

# You can also reference dynamic fields in filter expressions,
# and include them in output fields
res = collection.query(
    # demontrates the ways to reference a dynamic field.
    expr='$meta["dynamic_field_1"] > 10 and dynamic_field_2 == 10',
    # sets the names of the fields you want to retrieve from the search result.
    output_fields=['title', 'dynamic_field_1', 'dynamic_field_2'], 
)

sorted_res = sorted(res, key=lambda k: k['dynamic_field_1'])