DescribeReplicas()

This operation returns replica topology details, including shard leaders and node placement. Use it to inspect resource-group balancing and serving layout.

Status DescribeReplicas(const DescribeReplicasRequest& request, DescribeReplicasResponse& response)

Request Syntax

auto request = DescribeReplicasRequest()
    .WithCollectionName(collection_name)
    .WithDatabaseName(db_name);

DescribeReplicasRequest

REQUEST METHODS:

• WithCollectionName(const std::string& collection_name)

  Sets the collection whose replicas you want to inspect.

• WithDatabaseName(const std::string& db_name)

  Sets the target database. If omitted, the default database is used.

RETURNS:

Status with DescribeReplicasResponse

DescribeReplicasResponse

This class represents replica topology returned by DescribeReplicas().

const DescribeReplicasResponse& response = resp;

METHODS:

• const std::vector<ReplicaInfo>& Replicas() const

  Returns replica entries, including shard leaders and node placement details.

ReplicaInfo

This class represents one collection replica entry returned by DescribeReplicasResponse.

const ReplicaInfo& replica = response.Replicas()[0];

METHODS:

• int64_t ReplicaID() const

  Returns replica ID.

• int64_t CollectionID() const

  Returns collection ID.

• const std::vector<int64_t>& PartitionIDs() const

  Returns partition IDs served by this replica.

• const std::vector<ShardReplica>& ShardReplicas() const

  Returns shard-level routing and leader information.

• const std::vector<int64_t>& NodeIDs() const

  Returns node IDs participating in this replica.

• const std::string& ResourceGroupName() const

  Returns assigned resource group name.

• const std::unordered_map<std::string, int32_t>& NumOutboundNode() const

  Returns outbound node counts grouped by resource group.

ShardReplica

This class represents one shard replica entry inside a ReplicaInfo object.

const ShardReplica& shard = replica.ShardReplicas()[0];

METHODS:

• int64_t LeaderID() const

  Returns leader node ID for the shard.

• const std::string& LeaderAddress() const

  Returns network address of the shard leader.

• const std::string& ChannelName() const

  Returns DML channel name associated with the shard.

• const std::vector<int64_t>& NodeIDs() const

  Returns all nodes serving this shard replica.

EXCEPTIONS:

• StatusCode

  Check status.Code() and status.Message() for invalid collection names or unavailable replica metadata.

Example

#include <milvus/MilvusClientV2.h>
auto client = milvus::MilvusClientV2::Create();
milvus::ConnectParam connect_param{"http://localhost:19530", "root:Milvus"};
auto status = client->Connect(connect_param);
if (!status.IsOk()) {
    std::cout << status.Message() << std::endl;
}

milvus::DescribeReplicasResponse response;
status = client->DescribeReplicas(
    milvus::DescribeReplicasRequest()
        .WithCollectionName("my_collection"),
    response);
if (!status.IsOk()) {
    std::cout << status.Message() << std::endl;
}
for (const auto& replica : response.Replicas()) {
    std::cout << replica.ReplicaID() << std::endl;
}