加载和释放

加载集合是在集合中进行相似性搜索和查询的前提。本页主要介绍加载和释放 Collections 的步骤。

加载 Collections

加载 Collections 时，Milvus 会将索引文件和所有字段的原始数据加载到内存中，以便快速响应搜索和查询。在载入 Collections 后插入的实体会自动编入索引并载入。

以下代码片段演示了如何加载 Collections。

from pymilvus import MilvusClient

client = MilvusClient(
    uri="http://localhost:19530",
    token="root:Milvus"
)

# 7. Load the collection
client.load_collection(
    collection_name="customized_setup_1"
)

res = client.get_load_state(
    collection_name="customized_setup_1"
)

print(res)

# Output
#
# {
#     "state": "<LoadState: Loaded>"
# }

import io.milvus.v2.service.collection.request.LoadCollectionReq;
import io.milvus.v2.service.collection.request.GetLoadStateReq;
import io.milvus.v2.client.ConnectConfig;
import io.milvus.v2.client.MilvusClientV2;

String CLUSTER_ENDPOINT = "http://localhost:19530";
String TOKEN = "root:Milvus";

// 1. Connect to Milvus server
ConnectConfig connectConfig = ConnectConfig.builder()
        .uri(CLUSTER_ENDPOINT)
        .token(TOKEN)
        .build();

MilvusClientV2 client = new MilvusClientV2(connectConfig);

// 6. Load the collection
LoadCollectionReq loadCollectionReq = LoadCollectionReq.builder()
        .collectionName("customized_setup_1")
        .build();

client.loadCollection(loadCollectionReq);

// 7. Get load state of the collection
GetLoadStateReq loadStateReq = GetLoadStateReq.builder()
        .collectionName("customized_setup_1")
        .build();

Boolean res = client.getLoadState(loadStateReq);
System.out.println(res);

// Output:
// true

import { MilvusClient, DataType } from "@zilliz/milvus2-sdk-node";

const address = "http://localhost:19530";
const token = "root:Milvus";
const client = new MilvusClient({address, token});

// 7. Load the collection
res = await client.loadCollection({
    collection_name: "customized_setup_1"
})

console.log(res.error_code)

// Output
// 
// Success
// 

res = await client.getLoadState({
    collection_name: "customized_setup_1"
})

console.log(res.state)

// Output
// 
// LoadStateLoaded
// 

import (
    "context"
    "fmt"
    "log"

    "github.com/milvus-io/milvus/client/v2"
)

defer cli.Close(ctx)

loadTask, err := cli.LoadCollection(ctx, client.NewLoadCollectionOption("customized_setup_1"))
if err != nil {
    // handle error
}

// sync wait collection to be loaded
err = loadTask.Await(ctx)
if err != nil {
    // handle error
}

export CLUSTER_ENDPOINT="http://localhost:19530"
export TOKEN="root:Milvus"

curl --request POST \
--url "${CLUSTER_ENDPOINT}/v2/vectordb/collections/load" \
--header "Authorization: Bearer ${TOKEN}" \
--header "Content-Type: application/json" \
-d '{
    "collectionName": "customized_setup_1"
}'

# {
#     "code": 0,
#     "data": {}
# }

curl --request POST \
--url "${CLUSTER_ENDPOINT}/v2/vectordb/collections/get_load_state" \
--header "Authorization: Bearer ${TOKEN}" \
--header "Content-Type: application/json" \
-d '{
    "collectionName": "customized_setup_1"
}'

# {
#     "code": 0,
#     "data": {
#         "loadProgress": 100,
#         "loadState": "LoadStateLoaded",
#         "message": ""
#     }
# }

加载特定字段

Milvus 可以只加载搜索和查询所涉及的字段，从而减少内存使用并提高搜索性能。

下面的代码片段假定您创建了名为customized_setup_2 的 Collections，且该 Collection 中有名为my_id和my_vector 的两个字段。

client.load_collection(
    collection_name="customized_setup_1",
    # highlight-next-line
    load_fields=["my_id", "my_vector"] # Load only the specified fields
    skip_load_dynamic_field=True # Skip loading the dynamic field
)

res = client.get_load_state(
    collection_name="customized_setup_1"
)

print(res)

# Output
#
# {
#     "state": "<LoadState: Loaded>"
# }

// 6. Load the collection
LoadCollectionReq loadCollectionReq = LoadCollectionReq.builder()
        .collectionName("customized_setup_1")
        .loadFields(Arrays.asList("my_id", "my_vector"))
        .build();

client.loadCollection(loadCollectionReq);

// 7. Get load state of the collection
GetLoadStateReq loadStateReq = GetLoadStateReq.builder()
        .collectionName("customized_setup_1")
        .build();

Boolean res = client.getLoadState(loadStateReq);
System.out.println(res);

await client.load_collection({
  collection_name: "customized_setup_1",
  load_fields: ["my_id", "my_vector"], // Load only the specified fields
  skip_load_dynamic_field: true //Skip loading the dynamic field
});

const loadState = client.getCollectionLoadState({
    collection_name: "customized_setup_1",
})

console.log(loadState);

import (
    "context"
    "fmt"
    "log"

    "github.com/milvus-io/milvus/client/v2"
)

ctx, cancel := context.WithCancel(context.Background())
defer cancel()

loadTask, err := cli.LoadCollection(ctx, client.NewLoadCollectionOption("customized_setup_1").
    WithLoadFields("my_id", "my_vector"))
if err != nil {
    // handle error
}

// sync wait collection to be loaded
err = loadTask.Await(ctx)
if err != nil {
    // handle error
}

# REST 缺失

如果您选择加载特定字段，值得注意的是，只有load_fields 中包含的字段才能用作搜索和查询中的筛选器和输出字段。您应始终在load_fields 中包含主字段和至少一个向量字段的名称。

您还可以使用skip_load_dynamic_field 来确定是否加载动态字段。动态字段是一个保留的 JSON 字段，名为$meta，以键值对的形式保存所有非 Schema 定义的字段及其值。加载动态字段时，字段中的所有键都会被加载，并可用于过滤和输出。如果动态字段中的所有键都不参与元数据过滤和输出，请将skip_load_dynamic_field 设置为True 。

要在 Collections 加载后加载更多字段，需要先释放 Collections，以避免因索引更改而提示可能的错误。

释放 Collections

搜索和查询是内存密集型操作。为节约成本，建议释放当前不使用的 Collection。

下面的代码片段演示了如何释放一个 Collection。

# 8. Release the collection
client.release_collection(
    collection_name="custom_quick_setup"
)

res = client.get_load_state(
    collection_name="custom_quick_setup"
)

print(res)

# Output
#
# {
#     "state": "<LoadState: NotLoad>"
# }

import io.milvus.v2.service.collection.request.ReleaseCollectionReq;


// 8. Release the collection
ReleaseCollectionReq releaseCollectionReq = ReleaseCollectionReq.builder()
        .collectionName("custom_quick_setup")
        .build();

client.releaseCollection(releaseCollectionReq);

GetLoadStateReq loadStateReq = GetLoadStateReq.builder()
        .collectionName("custom_quick_setup")
        .build();
Boolean res = client.getLoadState(loadStateReq);
System.out.println(res);

// Output:
// false

// 8. Release the collection
res = await client.releaseCollection({
    collection_name: "custom_quick_setup"
})

console.log(res.error_code)

// Output
// 
// Success
// 

res = await client.getLoadState({
    collection_name: "custom_quick_setup"
})

console.log(res.state)

// Output
// 
// LoadStateNotLoad
// 

import (
    "context"

    "github.com/milvus-io/milvus/client/v2"
)

err := cli.ReleaseCollection(ctx, client.NewReleaseCollectionOption("custom_quick_setup"))
if err != nil {
    // handle error
}

export CLUSTER_ENDPOINT="http://localhost:19530"
export TOKEN="root:Milvus"

curl --request POST \
--url "${CLUSTER_ENDPOINT}/v2/vectordb/collections/release" \
--header "Authorization: Bearer ${TOKEN}" \
--header "Content-Type: application/json" \
-d '{
    "collectionName": "custom_quick_setup"
}'

# {
#     "code": 0,
#     "data": {}
# }

curl --request POST \
--url "${CLUSTER_ENDPOINT}/v2/vectordb/collections/get_load_state" \
--header "Authorization: Bearer ${TOKEN}" \
--header "Content-Type: application/json" \
-d '{
    "collectionName": "custom_quick_setup"
}'

# {
#     "code": 0,
#     "data": {
#         "loadProgress": 0,
#         "loadState": "LoadStateNotLoaded",
#         "message": ""
#     }
# }