Delete Entities

This topic describes how to delete entities in Milvus.

Milvus supports deleting entities by primary key filtered with boolean expression.

Deleted entities can still be retrieved immediately after the deletion if the consistency level is set lower than Strong.
Entities deleted beyond the pre-specified span of time for Time Travel cannot be retrieved again.
Frequent deletion operations will impact the system performance.

Prepare boolean expression

Prepare the boolean expression that filters the entities to delete.

Milvus only supports deleting entities with clearly specified primary keys, which can be achieved merely with the term expression in. Other operators can be used only in query or scalar filtering in vector search. See Boolean Expression Rules for more information.

The following example filters data with primary key values of 0 and 1.

Python Java GO Node.js C# Curl

expr = "book_id in [0,1]"

const expr = "book_id in [0,1]";

private static final String DELETE_EXPR = "book_id in [0,1]";

pks := entity.NewColumnInt64("book_id", []int64{0, 1})

var expression = "book_id in [0,1]";

# See the following section.

Delete entities

Delete the entities with the boolean expression you created. Milvus returns the ID list of the deleted entities.

Python Java GO Node.js C# Curl

from pymilvus import Collection
collection = Collection("book")      # Get an existing collection.
collection.delete(expr)

await milvusClient.deleteEntities({
  collection_name: "book",
  expr: expr,
});

client.DeleteByPks("book", pks)

milvusClient.delete(
  DeleteParam.newBuilder()
    .withCollectionName("book")
    .withExpr(DELETE_EXPR)
    .build()
);

await milvusClient.GetCollection("book").DeleteAsync(expression);

curl -X 'POST' \
  '${MILVUS_HOST}:${MILVUS_PORT}/v1/vector/delete' \
  -H 'Authorization: Bearer ${TOKEN}' \
  -H 'accept: application/json' \
  -H 'Content-Type: application/json' \
  -d '{
       "collectionName": "collection1",
       "id": 1
     }'

Output:

{
    "code": 200,
    "data": {}
}

Parameter	Description
`expr`	Boolean expression that specifies the entities to delete.
`partition_name` (optional)	Name of the partition to delete entities from.

Parameter	Description
`collection_name`	Name of the collection to delete entities from.
`expr`	Boolean expression that specifies the entities to delete.
`partition_name` (optional)	Name of the partition to delete entities from.

Parameter	Description
`CollectionName`	Name of the collection to delete entities from.
`expr`	Boolean expression that specifies the entities to delete.
`PartitionName` (optional)	Name of the partition to delete entities from.

Parameter	Description
`collName`	Name of the collection to delete entities from.
`partitionName` (optional)	Name of the partition to delete entities from.
`ids`	A set of ids to delete.

Parameter	Description
`CollectionName`	Name of the collection to delete entities from. You should get a collection and call its `InsertAsync` with the following parameters.
`expression`	Boolean expression that specifies the entities to delete.
`PartitionName` (optional)	Name of the partition to delete entities from.

Parameter	Description
`collectionName`	The name of the collection to which this operation applies.
`id`	The ID of the entity to drop.

What's next

Learn more basic operations of Milvus: