// Copyright 2022 Google LLC

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

syntax = "proto2";

package kv_server;

import "public/base_types.proto";

import "riegeli/records/records_metadata.proto";

// Metadata specific to DELTA files.

message DeltaMetadata {}

// Metadata specific to SNAPSHOT files.

message SnapshotMetadata {

// [Required]

// (1) Name of the previous snapshot file used to generate this snapshot or

// (2) Name of the oldest delta file included in the snapshot.

optional string starting_file = 1;

// [Required]

// Name of the most recent delta file included in the snapshot.

optional string ending_delta_file = 2;

}

// Sharding metadata for DELTA and SNAPSHOT files.

message ShardingMetadata {

// The shard number that data in this file belong to.

optional int64 shard_num = 1;

}

// Work in progress. Do not use.

// Metadata specific to LOGICAL_SHARDING_CONFIG files.

message LogicalShardingConfigMetadata {

// [Required] Number of logical shards, recommended to be a power of 2 and

// much larger than `num_physical_shards`. Data records are assigned to

// logical shards and logical shards map to physical shards (actual data

// servers).

optional int32 num_logical_shards = 1;

// [Required] Number of physical shards. Maps to actual physical data servers

// that store data records. Each physical shard can be responsible for data

// records assigned to different logical shards.

optional int32 num_physical_shards = 2;

// [Required] sha256sum of the mapping between logical shards and physical

// shards. This is fixed for each logical sharding config file, but can be

// different between files with the same number of logical and physical

// shards.

optional string shard_mapping_sha256sum = 3;

// [Required] Unix timestamp when the logical sharding config file was

// created.

optional int64 creation_timestamp = 4;

}

// All K/V server metadata related to one riegeli file.

message KVFileMetadata {

// All records in one file are from this namespace.

optional KeyNamespace.Enum key_namespace = 1 [deprecated = true];

oneof file_type {

DeltaMetadata delta = 2;

SnapshotMetadata snapshot = 3;

LogicalShardingConfigMetadata logical_sharding_config = 5;

}

optional ShardingMetadata sharding_metadata = 4;

}

extend riegeli.RecordsMetadata {

optional KVFileMetadata kv_file_metadata = 20220706;

}