milvus/pkg/proto/streaming.proto

syntax = "proto3";

package milvus.proto.streaming;

option go_package = "github.com/milvus-io/milvus/pkg/v2/proto/streamingpb";

import "data_coord.proto";
import "messages.proto";
import "common.proto";
import "milvus.proto";
import "schema.proto";
import "google/protobuf/empty.proto";
import "google/protobuf/any.proto";
import "google/protobuf/field_mask.proto";

//
// Common
//

// PChannelAccessMode is the access mode of a pchannel.
enum PChannelAccessMode {
    PCHANNEL_ACCESS_READWRITE = 0;  // read and write by default.
    PCHANNEL_ACCESS_READONLY = 1;  // read only.
}

// PChannelInfo is the information of a pchannel info, should only keep the
// basic info of a pchannel. It's used in many rpc and meta, so keep it simple.
message PChannelInfo {
    string name = 1;  // channel name
    int64 term  = 2;  // A monotonic increasing term, every time the channel is
                      // recovered or moved to another streamingnode, the term
                      // will increase by meta server.
    PChannelAccessMode access_mode = 3;  // access mode of the channel.
}

// PChannelAssignmentLog is the log of meta information of a pchannel, should
// only keep the data that is necessary to persistent.
message PChannelAssignmentLog {
    int64 term = 1;  // term when server assigned.
    StreamingNodeInfo node =
        2;  // streaming node that the channel is assigned to.
    PChannelAccessMode access_mode = 3;  // access mode of the channel.
}

// PChannelMetaState
enum PChannelMetaState {
    PCHANNEL_META_STATE_UNKNOWN = 0;  // should never used.
    PCHANNEL_META_STATE_UNINITIALIZED =
        1;  // channel is uninitialized, never assgined to any streaming node.
    PCHANNEL_META_STATE_ASSIGNING =
        2;  // new term is allocated, but not determined to be assgined.
    PCHANNEL_META_STATE_ASSIGNED =
        3;  // channel is assigned to a streaming node.
    PCHANNEL_META_STATE_UNAVAILABLE =
        4;  // channel is unavailable at this term.
}

// PChannelMeta is the meta information of a pchannel, should only keep the data
// that is necessary to persistent. It's only used in meta, so do not use it in
// rpc.
message PChannelMeta {
    PChannelInfo channel   = 1;  // keep the meta info that current assigned to.
    StreamingNodeInfo node = 2;  // nil if channel is not uninitialized.
    PChannelMetaState state = 3;  // state of the channel.
    repeated PChannelAssignmentLog histories =
        4;  // keep the meta info assignment log that used to be assigned to.
    uint64 last_assign_timestamp_seconds = 5; // The last assigned timestamp in seconds.
}

// CChannelMeta is the meta information of a control channel.
message CChannelMeta {
    string pchannel = 1; // the pchannel that control channel locate on.
}

// StreamingVersion is the version of the streaming service.
message StreamingVersion {
    int64 version = 1; // version of the streaming,
    // null if there's no streaming service running, the cluster is upgrading from 2.5.x or cluster startup.
    // 1 means the first version of streaming service is already running.
}

// VersionPair is the version pair of global and local.
message VersionPair {
    int64 global = 1;
    int64 local  = 2;
}

// BroadcastTaskState is the state of the broadcast task.
enum BroadcastTaskState {
    BROADCAST_TASK_STATE_UNKNOWN = 0;          // should never used.
    BROADCAST_TASK_STATE_PENDING = 1;          // task is pending.
    BROADCAST_TASK_STATE_DONE = 2;             // task has been broadcasted and acknowledged, the resource lock is released, and the persisted task can be cleared.
    BROADCAST_TASK_STATE_WAIT_ACK = 3 [deprecated = true];         // task has been broadcasted, waiting for ack, the resource lock is still acquired by some vchannels.
    BROADCAST_TASK_STATE_REPLICATED = 4;       // task is replicated from the source cluster, the resource lock isn't acquired, so the execution order should be protected by the order of broadcastID.
    BROADCAST_TASK_STATE_TOMBSTONE = 5;        // task is tombstone, it's used to mark the task is already acked, but for idempotency and deduplication, it will be kept in recovery stroage for a while.
}

// BroadcastTask is the task to broadcast the messake.
message BroadcastTask {
    messages.Message message = 1;    // message to be broadcast.
    BroadcastTaskState state = 2;    // state of the task.
    bytes acked_vchannel_bitmap = 3 [deprecated = true]; // deprecated, use acked_checkpoints instead.
    repeated AckedCheckpoint acked_checkpoints = 4; // given vchannels that have been acked, the size of bitmap is same with message.BroadcastHeader().VChannels.
}

// AckedResult is the result of the ack.
// It's a helper proto to help managing the consuming of broadcast message at coordinator.
message AckedResult {
    repeated string channels = 1; // may be pchannel name or vchannel name.
    repeated AckedCheckpoint acked_checkpoints = 2; // always same length with channels, not nil if acked.
}

// AckedCheckpoint is the checkpoint that has been acked.
message AckedCheckpoint {
    common.MessageID message_id = 1;  // the message id that has been acked.
    common.MessageID last_confirmed_message_id = 2; // the last confirmed message id that has been acked.
    uint64 time_tick = 3; // the time tick of the message that has been acked.
}

//
// Milvus Service
//

service StreamingNodeStateService {
    rpc GetComponentStates(milvus.GetComponentStatesRequest)
        returns (milvus.ComponentStates) {}
}

//
// StreamingCoordBroadcastService
//

// StreamingCoordBroadcastService is the broadcast service for streaming coord.
service StreamingCoordBroadcastService {
    // Broadcast receives broadcast messages from other component and make sure that the message is broadcast to all wal.
    // It performs an atomic broadcast to all wal, achieve eventual consistency.
    rpc Broadcast(BroadcastRequest) returns (BroadcastResponse) {}

    // Ack acknowledge broadcast message is consumed.
    rpc Ack(BroadcastAckRequest) returns (BroadcastAckResponse) {}
}

// BroadcastRequest is the request of the Broadcast RPC.
message BroadcastRequest {
    messages.Message message = 1; // message to be broadcast.
}

// BroadcastResponse is the response of the Broadcast RPC.
message BroadcastResponse {
    map<string,ProduceMessageResponseResult> results = 1; 
    uint64 broadcast_id = 2;
}

message BroadcastAckRequest {
    uint64 broadcast_id = 1 [deprecated = true]; // broadcast id.
    string vchannel = 2 [deprecated = true];     // the vchannel that acked the message.
    common.ImmutableMessage message = 3;       // the message that to be acked.
}

message BroadcastAckResponse {
}

//
// StreamingCoordAssignmentService
//

// StreamingCoordAssignmentService is the global log management service.
// Server: log coord. Running on every log node.
// Client: all log publish/consuming node.
service StreamingCoordAssignmentService {
    // UpdateReplicateConfiguration applies a full replacement of the current
    // replication configuration across Milvus clusters.
    //
    // Semantics:
    //   - The provided ReplicateConfiguration completely replaces any existing
    //     configuration persisted in the metadata store.
    //   - Passing an empty ReplicateConfiguration is treated as a "clear"
    //     operation, effectively removing all replication configuration.
    //   - The RPC is expected to be idempotent: submitting the same configuration
    //     multiple times must not cause side effects.
    rpc UpdateReplicateConfiguration(UpdateReplicateConfigurationRequest)
        returns (UpdateReplicateConfigurationResponse) {}

    // UpdateWALBalancePolicy is used to update the WAL balance policy.
    // The policy is used to control the balance of the WAL.
    rpc UpdateWALBalancePolicy(UpdateWALBalancePolicyRequest) returns (UpdateWALBalancePolicyResponse) {
        option deprecated = true;
    };

    // AssignmentDiscover is used to discover all log nodes managed by the
    // streamingcoord. Channel assignment information will be pushed to client
    // by stream.
    rpc AssignmentDiscover(stream AssignmentDiscoverRequest)
        returns (stream AssignmentDiscoverResponse) {}
}

message UpdateReplicateConfigurationRequest {
    common.ReplicateConfiguration configuration = 1;
}

// UpdateReplicateConfigurationResponse is the response of UpdateReplicateConfiguration service
message UpdateReplicateConfigurationResponse {}

// UpdateWALBalancePolicyRequest is the request to update the WAL balance policy.
message UpdateWALBalancePolicyRequest {
    WALBalancePolicyConfig config = 1;
    WALBalancePolicyNodes nodes = 2;
    google.protobuf.FieldMask update_mask = 3;
}

message WALBalancePolicyConfig {
    bool allow_rebalance = 1;
}

message WALBalancePolicyNodes {
    repeated int64 freeze_node_ids = 1;   // nodes that will be frozen.
    repeated int64 defreeze_node_ids = 2; // nodes that will be defrozen.
}

message UpdateWALBalancePolicyResponse {
    WALBalancePolicyConfig config = 1;    // return current configuration of WAL balance policy.
    repeated int64 freeze_node_ids = 2;   // nodes that are frozen.
}

// AssignmentDiscoverRequest is the request of Discovery
message AssignmentDiscoverRequest {
    oneof command {
        ReportAssignmentErrorRequest report_error =
            1;  // report streaming error, trigger reassign right now.
        CloseAssignmentDiscoverRequest close = 2;  // close the stream.
    }
}

// ReportAssignmentErrorRequest is the request to report assignment error
// happens.
message ReportAssignmentErrorRequest {
    PChannelInfo pchannel = 1;  // channel
    StreamingError err    = 2;  // error happend on log node
}

// CloseAssignmentDiscoverRequest is the request to close the stream.
message CloseAssignmentDiscoverRequest {}

// AssignmentDiscoverResponse is the response of Discovery
message AssignmentDiscoverResponse {
    oneof response {
        FullStreamingNodeAssignmentWithVersion full_assignment =
            1;  // all assignment info.
        // TODO: may be support partial assignment info in future.
        CloseAssignmentDiscoverResponse close = 2;
    }
}

// FullStreamingNodeAssignmentWithVersion is the full assignment info of a log
// node with version.
message FullStreamingNodeAssignmentWithVersion {
    VersionPair version                                   = 1;
    repeated StreamingNodeAssignment assignments          = 2;
    CChannelAssignment cchannel                           = 3; // Where the control channel located.
    common.ReplicateConfiguration replicate_configuration = 4;
}

// CChannelAssignment is the assignment info of a control channel.
message CChannelAssignment {
    CChannelMeta meta = 1;
}

message CloseAssignmentDiscoverResponse {}

// StreamingNodeInfo is the information of a streaming node.
message StreamingNodeInfo {
    int64 server_id = 1;
    string address  = 2;
}

// StreamingNodeAssignment is the assignment info of a streaming node.
message StreamingNodeAssignment {
    StreamingNodeInfo node         = 1;
    repeated PChannelInfo channels = 2;
}

// DeliverPolicy is the policy to deliver message.
message DeliverPolicy {
    oneof policy {
        google.protobuf.Empty all    = 1;  // deliver all messages.
        google.protobuf.Empty latest = 2;  // deliver the latest message.
        common.MessageID start_from =
            3;  // deliver message from this message id. [startFrom, ...]
        common.MessageID start_after =
            4;  // deliver message after this message id. (startAfter, ...]
    }
}

// DeliverFilter is the filter to deliver message.
message DeliverFilter {
    oneof filter {
        DeliverFilterTimeTickGT time_tick_gt   = 1;
        DeliverFilterTimeTickGTE time_tick_gte = 2;
        DeliverFilterMessageType message_type  = 3;
    }
}

// DeliverFilterTimeTickGT is the filter to deliver message with time tick
// greater than this value.
message DeliverFilterTimeTickGT {
    uint64 time_tick =
        1;  // deliver message with time tick greater than this value.
}

// DeliverFilterTimeTickGTE is the filter to deliver message with time tick
// greater than or equal to this value.
message DeliverFilterTimeTickGTE {
    uint64 time_tick = 1;  // deliver message with time tick greater than or
                           // equal to this value.
}

message DeliverFilterMessageType {
    // deliver message with message type.
    repeated messages.MessageType message_types = 1;
}

// StreamingCode is the error code for log internal component.
enum StreamingCode {
    STREAMING_CODE_OK                     = 0;
    STREAMING_CODE_CHANNEL_NOT_EXIST      = 1;  // channel not exist
    STREAMING_CODE_CHANNEL_FENCED         = 2;  // channel is fenced
    STREAMING_CODE_ON_SHUTDOWN            = 3;  // component is on shutdown
    STREAMING_CODE_INVALID_REQUEST_SEQ    = 4;  // invalid request sequence
    STREAMING_CODE_UNMATCHED_CHANNEL_TERM = 5;  // unmatched channel term
    STREAMING_CODE_IGNORED_OPERATION      = 6;  // ignored operation
    STREAMING_CODE_INNER                  = 7;  // underlying service failure.
    STREAMING_CODE_INVAILD_ARGUMENT       = 8;  // invalid argument
    STREAMING_CODE_TRANSACTION_EXPIRED    = 9;  // transaction expired
    STREAMING_CODE_INVALID_TRANSACTION_STATE = 10;  // invalid transaction state
    STREAMING_CODE_UNRECOVERABLE          = 11; // unrecoverable error
    STREAMING_CODE_RESOURCE_ACQUIRED      = 12; // resource is acquired by other operation
    STREAMING_CODE_REPLICATE_VIOLATION    = 13; // replicate violation
    STREAMING_CODE_UNKNOWN                   = 999;  // unknown error
}

// StreamingError is the error type for log internal component.
message StreamingError {
    StreamingCode code = 1;
    string cause       = 2;
}

//
// StreamingNodeHandlerService
//

// StreamingNodeHandlerService is the service to handle log messages.
// All handler operation will be blocked until the channel is ready read or
// write on that log node. Server: all log node. Running on every log node.
// Client: all log produce or consuming node.
service StreamingNodeHandlerService {
    // GetReplicateCheckpoint returns the WAL checkpoint that will be used to create scanner
    // from the correct position, ensuring no duplicate or missing messages.
    rpc GetReplicateCheckpoint(GetReplicateCheckpointRequest) returns (GetReplicateCheckpointResponse) {}

    // Produce is a bi-directional streaming RPC to send messages to a channel.
    // All messages sent to a channel will be assigned a unique messageID.
    // The messageID is used to identify the message in the channel.
    // The messageID isn't promised to be monotonous increasing with the
    // sequence of responsing. Error: If channel isn't assign to this log node,
    // the RPC will return error CHANNEL_NOT_EXIST. If channel is moving away to
    // other log node, the RPC will return error CHANNEL_FENCED.
    rpc Produce(stream ProduceRequest) returns (stream ProduceResponse) {};

    // Consume is a server streaming RPC to receive messages from a channel.
    // All message after given startMessageID and excluding will be sent to the
    // client by stream. If no more message in the channel, the stream will be
    // blocked until new message coming. Error: If channel isn't assign to this
    // log node, the RPC will return error CHANNEL_NOT_EXIST. If channel is
    // moving away to other log node, the RPC will return error CHANNEL_FENCED.
    rpc Consume(stream ConsumeRequest) returns (stream ConsumeResponse) {};
}

// GetReplicateCheckpointRequest is the request of GetReplicateCheckpoint service.
message GetReplicateCheckpointRequest {
  PChannelInfo pchannel = 1;
}

// GetReplicateCheckpointResponse is the response of GetReplicateCheckpoint service.
message GetReplicateCheckpointResponse {
  common.ReplicateCheckpoint checkpoint = 1;
}

// ProduceRequest is the request of the Produce RPC.
// Channel name will be passthrough in the header of stream bu not in the
// request body.
message ProduceRequest {
    oneof request {
        ProduceMessageRequest produce = 1;
        CloseProducerRequest close    = 2;
    }
}

// CreateProducerRequest is the request of the CreateProducer RPC.
// CreateProducerRequest is passed in the header of stream.
message CreateProducerRequest {
    PChannelInfo pchannel = 1;
}

// ProduceMessageRequest is the request of the Produce RPC.
message ProduceMessageRequest {
    int64 request_id         = 1;  // request id for reply.
    messages.Message message = 2;  // message to be sent.
}

// CloseProducerRequest is the request of the CloseProducer RPC.
// After CloseProducerRequest is requested, no more ProduceRequest can be sent.
message CloseProducerRequest {}

// ProduceResponse is the response of the Produce RPC.
message ProduceResponse {
    oneof response {
        CreateProducerResponse create  = 1;
        ProduceMessageResponse produce = 2;
        CloseProducerResponse close    = 3;
    }
}

// CreateProducerResponse is the result of the CreateProducer RPC.
message CreateProducerResponse {
    string wal_name          = 1 [deprecated = true];  // wal name at server side.
    int64 producer_server_id = 2;   // A unique producer server id on streamingnode
           // for this producer in streamingnode lifetime.
    // Is used to identify the producer in streamingnode for other unary grpc
    // call at producer level.
}

// ProduceMessageResponse is the response of the ProduceMessage RPC.
message ProduceMessageResponse {
    int64 request_id = 1;
    oneof response {
        ProduceMessageResponseResult result = 2;
        StreamingError error                = 3;
    }
}

// ProduceMessageResponseResult is the result of the produce message streaming
// RPC.
message ProduceMessageResponseResult {
    common.MessageID id = 1;  // the offset of the message in the channel.
    uint64 timetick       = 2;  // the timetick of that message sent.
    messages.TxnContext txnContext = 3;  // the txn context of the message.
    google.protobuf.Any extra      = 4;  // the extra message.
    common.MessageID last_confirmed_id = 5;  // the last confirmed message id.
}

// CloseProducerResponse is the result of the CloseProducer RPC.
message CloseProducerResponse {}

// ConsumeRequest is the request of the Consume RPC.
// Add more control block in future.
message ConsumeRequest {
    oneof request {
        CreateVChannelConsumerRequest create_vchannel_consumer = 1;
        CreateVChannelConsumersRequest create_vchannel_consumers =
            2; // Create multiple vchannel consumers, used for recovery in future.
        CloseVChannelConsumerRequest close_vchannel = 3;
        CloseConsumerRequest close = 4;
    }
}

// CloseConsumerRequest is the request of the CloseConsumer RPC.
// After CloseConsumerRequest is requested, no more ConsumeRequest can be sent.
message CloseConsumerRequest {}

// CreateConsumerRequest is the request of the CreateConsumer RPC.
// CreateConsumerRequest is passed in the header of stream.
message CreateConsumerRequest {
    PChannelInfo pchannel                  = 1;
}

message CreateVChannelConsumersRequest {
    repeated CreateVChannelConsumerRequest create_vchannels = 1;
}

// CreateVChannelConsumerRequest is the request of the CreateVChannelConsumer
// RPC. It's used to create a new vchannel consumer at server side.
message CreateVChannelConsumerRequest {
    string vchannel = 1;
    DeliverPolicy deliver_policy           = 2;  // deliver policy.
    repeated DeliverFilter deliver_filters = 3;  // deliver filter.
}

// ConsumeMessageRequest is the request of the Consume RPC.
message CreateVChannelConsumersResponse {
    repeated CreateVChannelConsumerResponse create_vchannels = 1;
}

// CreateVChannelConsumerResponse is the response of the CreateVChannelConsumer
// RPC.
message CreateVChannelConsumerResponse {
    oneof response {
        int64 consumer_id = 1;
        StreamingError error = 2;
    }
}

// CloseVChannelConsumerRequest is the request of the CloseVChannelConsumer RPC.
message CloseVChannelConsumerRequest {
    int64 consumer_id = 1;
}

// CloseVChannelConsumerResponse is the response of the CloseVChannelConsumer
// RPC.
message CloseVChannelConsumerResponse {
    int64 consumer_id = 1;
}

// ConsumeResponse is the reponse of the Consume RPC.
message ConsumeResponse {
    oneof response {
        CreateConsumerResponse create = 1;
        ConsumeMessageReponse consume = 2;
        CreateVChannelConsumerResponse create_vchannel = 3;
        CreateVChannelConsumersResponse create_vchannels = 4;
        CloseVChannelConsumerResponse close_vchannel = 5;
        CloseConsumerResponse close = 6;
    }
}

message CreateConsumerResponse {
    string wal_name          = 1 [deprecated = true];  // wal name at server side.
    // A unique consumer id on streamingnode for this
    // consumer in streamingnode lifetime.
    int64 consumer_server_id = 2;
}

message ConsumeMessageReponse {
    int64 consumer_id = 1;
    common.ImmutableMessage message = 2;
}

message CloseConsumerResponse {}

//
// StreamingNodeManagerService
//

// StreamingNodeManagerService is the log manage operation on log node.
// Server: all log node. Running on every log node.
// Client: log coord. There should be only one client globally to call this
// service on all streamingnode.
service StreamingNodeManagerService {
    // Assign is a unary RPC to assign a channel on a log node.
    // Block until the channel assignd is ready to read or write on the log
    // node. Error: If the channel already exists, return error with code
    // CHANNEL_EXIST.
    rpc Assign(StreamingNodeManagerAssignRequest)
        returns (StreamingNodeManagerAssignResponse) {};

    // Remove is unary RPC to remove a channel on a log node.
    // Data of the channel on flying would be sent or flused as much as
    // possible. Block until the resource of channel is released on the log
    // node. New incoming request of handler of this channel will be rejected
    // with special error. Error: If the channel does not exist, return error
    // with code CHANNEL_NOT_EXIST.
    rpc Remove(StreamingNodeManagerRemoveRequest)
        returns (StreamingNodeManagerRemoveResponse) {};

    // rpc CollectStatus() ...
    // CollectStatus is unary RPC to collect all avaliable channel info and load
    // balance info on a log node. Used to recover channel info on log coord,
    // collect balance info and health check.
    rpc CollectStatus(StreamingNodeManagerCollectStatusRequest)
        returns (StreamingNodeManagerCollectStatusResponse) {};
}

// StreamingManagerAssignRequest is the request message of Assign RPC.
message StreamingNodeManagerAssignRequest {
    PChannelInfo pchannel = 1;
}

message StreamingNodeManagerAssignResponse {}

message StreamingNodeManagerRemoveRequest {
    PChannelInfo pchannel = 1;
}

message StreamingNodeManagerRemoveResponse {}

message StreamingNodeManagerCollectStatusRequest {}

message StreamingNodeMetrics {
    repeated StreamingNodeWALMetrics wals = 1;
}

message StreamingNodeWALMetrics {
    PChannelInfo info = 1;
    oneof metrics {
        StreamingNodeRWWALMetrics rw = 2;
        StreamingNodeROWALMetrics ro = 3;
    };
}

message StreamingNodeRWWALMetrics {
    uint64 mvcc_time_tick = 1; // The mvcc time tick of the pchannel.
    uint64 recovery_time_tick = 2; // The recovery time tick of the pchannel.
}

message StreamingNodeROWALMetrics {
}

message StreamingNodeManagerCollectStatusResponse {
    StreamingNodeMetrics metrics = 1;
}

///
/// VChannelMeta 
///
// VChannelMeta is the meta information of a vchannel.
// We need to add vchannel meta in wal meta, so the wal can recover the information of it.
// The vchannel meta is also used to store the vchannel operation result, such as shard-splitting.
message VChannelMeta {
    string vchannel = 1; // vchannel name.
    VChannelState state = 2; // vchannel state.
    CollectionInfoOfVChannel collection_info = 3; // if the channel is belong to a collection, the collection info will be setup.
    uint64 checkpoint_time_tick = 4; // The timetick of checkpoint, the meta already see the message at this timetick.
}

// CollectionInfoOfVChannel is the collection info in vchannel.
message CollectionInfoOfVChannel {
    int64 collection_id = 1; // collection id.
    repeated PartitionInfoOfVChannel partitions  = 2; // partitions.
    repeated CollectionSchemaOfVChannel schemas = 3; // The schemas of the vchannel.
}

// CollectionSchemaOfVChannel is the collection schema in vchannel.
message CollectionSchemaOfVChannel {
    schema.CollectionSchema schema = 1; // The schemas of the vchannel.
    uint64 checkpoint_time_tick = 2; // The timetick of the schema changed, also the version of the schema.
    VChannelSchemaState state = 3; // The state of the schema.
}

// PartitionInfoOfVChannel is the partition info in vchannel.
message PartitionInfoOfVChannel {
    int64 partition_id = 1; // partition id.
}

// VChannelState is the state of vchannel
enum VChannelState {
    VCHANNEL_STATE_UNKNOWN = 0;  // should never used.
    VCHANNEL_STATE_NORMAL  = 1;  // vchannel is normal.
    VCHANNEL_STATE_DROPPED = 2;  // vchannel is dropped.
    // VCHANNEL_STATE_SPLITTED = 3; // TODO: vchannel is splitted to other vchannels, used to support shard-splitting.
}

// VChannelSchemaState is the state of vchannel schema.
enum VChannelSchemaState {
    VCHANNEL_SCHEMA_STATE_UNKNOWN = 0; // should never used.
    VCHANNEL_SCHEMA_STATE_NORMAL = 1; // vchannel schema is normal.
    VCHANNEL_SCHEMA_STATE_DROPPED = 2; // vchannel schema is dropped.
}

///
/// SegmentAssignment
///
// SegmentAssignmentMeta is the stat of segment assignment.
// These meta is only used to recover status at streaming node segment
// assignment, don't use it outside.
// Used to storage the segment assignment stat
// at meta-store. The WAL use it to determine when to make the segment sealed.
message SegmentAssignmentMeta {
    int64 collection_id          = 1;
    int64 partition_id           = 2;
    int64 segment_id             = 3;
    string vchannel              = 4;
    SegmentAssignmentState state = 5;
    SegmentAssignmentStat stat   = 6;
    int64 storage_version        = 7; // only available if level is L1 or Legacy.
    uint64 checkpoint_time_tick  = 8; // The timetick of checkpoint, the meta already see the message at this timetick.
}

enum SegmentAssignmentState {
    SEGMENT_ASSIGNMENT_STATE_UNKNOWN = 0;  // should never used.
    SEGMENT_ASSIGNMENT_STATE_GROWING = 1;
    SEGMENT_ASSIGNMENT_STATE_FLUSHED = 2;
}

// SegmentAssignmentStat is the stat of segment assignment.
message SegmentAssignmentStat {
    uint64 max_binary_size                    = 1;
    uint64 modified_rows                      = 2;
    uint64 modified_binary_size               = 3;
    int64 create_timestamp                    = 4;
    int64 last_modified_timestamp             = 5;
    uint64 binlog_counter                     = 6;
    uint64 create_segment_time_tick           = 7; // The timetick of create segment message in wal.
    data.SegmentLevel level                   = 8; // The level of the segment, only L0 or L1.
    uint64 max_rows                           = 9; // The max rows of the segment.
}

// The WALCheckpoint that is used to recovery the wal scanner.
message WALCheckpoint {
    common.MessageID message_id = 1; // From here to recover all uncommited info.
    // e.g., primary key index, segment assignment info, vchannel info...
    // because current data path flush is slow, and managed by the coordinator, current current is not apply to it.
    // 
    // because the data path flush is slow, so we add a new checkpoint here to promise fast recover the wal state from log.
    uint64 time_tick = 2; // The timetick of checkpoint, keep consistecy with message_id.
    // It's a hint for easier debugging.
    int64 recovery_magic = 3; // The recovery version of the checkpoint, it's used to hint the future recovery info upgrading.
    // The wal name of the checkpoint.
    common.ReplicateConfiguration replicate_config = 4; // if the wal join a replicated clusters, the replicate config is not null,
    common.ReplicateCheckpoint replicate_checkpoint = 5; // if the wal is replicated from remote cluster, the checkpoint is not null,
    // It's used to recover the replication state for remote cluster.
}

// ReplicateConfigurationMeta is the replicate configuration of the wal.
message ReplicateConfigurationMeta {
    common.ReplicateConfiguration replicate_configuration = 1;
    AckedResult acked_result = 2; // a acked helper to help managing the consuming of PutReplicateConfigMessageV2 message at coordinator.
}

message ReplicatePChannelMeta {
    string source_channel_name          = 1;
    string target_channel_name          = 2;
    common.MilvusCluster target_cluster = 3;
    common.ReplicateCheckpoint initialized_checkpoint = 4;
}