foundationdb/fdbserver/core/BackupPartitionMap.cpp

262 lines
10 KiB
C++

/*
* BackupPartitionMap.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2026 Apple Inc. and the FoundationDB project authors
*
* 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.
*/
#include "fdbserver/core/BackupPartitionMap.h"
#include "fdbclient/JsonBuilder.h"
#include "fdbclient/KeyRangeMap.h"
#include "fdbclient/Knobs.h"
#include "fdbclient/SystemData.h"
std::string serializePartitionListJSON(PartitionMap const& partitionMap) {
JsonBuilderObject root;
JsonBuilderArray partitionsArray;
for (const auto& [tag, partitionList] : partitionMap) {
for (const auto& partition : partitionList) {
JsonBuilderObject partitionObj;
partitionObj["partitionId"] = partition.partitionId;
partitionObj["beginKey"] = partition.ranges.begin.printable();
partitionObj["endKey"] = partition.ranges.end.printable();
partitionsArray.push_back(partitionObj);
}
}
root["partitions"] = partitionsArray;
root["totalPartitions"] = partitionsArray.size();
return root.getJson();
}
// KeyRangeMap guarantees that key ranges are contiguous with no gaps in shards.
Future<std::vector<KeyRange>> calculateBackupPartitionKeyRanges(KeyRangeMap<ShardTrackedData>* shards) {
const int NUM_PARTITIONS = CLIENT_KNOBS->BACKUP_NUM_OF_PARTITIONS;
std::vector<std::pair<KeyRange, int64_t>> userShards; // Pair of shard key range and shard size in bytes.
int64_t totalBytes = 0;
// Step 1: Collect shard sizes
while (true) {
bool needWait = false;
Future<Void> onChange;
userShards.clear();
totalBytes = 0;
for (auto it : shards->intersectingRanges(normalKeys)) {
// Await trackShardMetrics to populate stats in cache (waits for notification from background actor, no
// RPC).
if (!it->value().stats->get().present()) {
onChange = it->value().stats->onChange();
needWait = true;
TraceEvent("BackupPartitionShardMetricsWait")
.detail("ShardBegin", it->range().begin)
.detail("ShardEnd", it->range().end);
break;
}
totalBytes += it->value().stats->get().get().metrics.bytes;
userShards.push_back(std::make_pair(it.range(), it->value().stats->get().get().metrics.bytes));
}
if (!needWait) {
break;
}
co_await onChange;
}
// Step 2: Partition the shards
// Integer division is acceptable here as any rounding remainder is added to the last partition.
int64_t targetBytesPerPartition = totalBytes / NUM_PARTITIONS;
std::vector<KeyRange> partitionKeyRanges;
int64_t currentPartitionBytes = 0;
Key partitionStart = normalKeys.begin;
for (int i = 0; i < userShards.size(); i++) {
currentPartitionBytes += userShards[i].second;
// Checks if new partition should be started.
if ((currentPartitionBytes >= targetBytesPerPartition) || (i == userShards.size() - 1)) {
partitionKeyRanges.push_back(KeyRangeRef(partitionStart, userShards[i].first.end));
partitionStart = userShards[i].first.end;
currentPartitionBytes = 0;
}
}
co_return partitionKeyRanges;
}
TEST_CASE("/BackupPartitionMap/calculateBackupPartitionKeyRanges/NoUserShards") {
ShardTrackedData defaultData;
StorageMetrics zeroMetrics;
zeroMetrics.bytes = 0;
zeroMetrics.bytesWrittenPerKSecond = 0;
zeroMetrics.bytesReadPerKSecond = 0;
zeroMetrics.iosPerKSecond = 0;
zeroMetrics.opsReadPerKSecond = 0;
ShardMetrics zeroShard(zeroMetrics, 0.0, 1);
defaultData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(zeroShard);
KeyRangeMap<ShardTrackedData> shards(defaultData);
ShardTrackedData systemData;
systemData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(zeroShard);
shards.insert(systemKeys, systemData);
std::vector<KeyRange> partitions = co_await calculateBackupPartitionKeyRanges(&shards);
ASSERT(partitions.size() == 1);
ASSERT(partitions[0].begin == normalKeys.begin);
ASSERT(partitions[0].end == normalKeys.end);
}
TEST_CASE("/BackupPartitionMap/calculateBackupPartitionKeyRanges/SingleShard") {
ShardTrackedData defaultData;
defaultData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>();
KeyRangeMap<ShardTrackedData> shards(defaultData);
ShardTrackedData data;
StorageMetrics metrics;
metrics.bytes = 1000000;
ShardMetrics shardMetrics(metrics, 0.0, 1);
data.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(shardMetrics);
shards.insert(normalKeys, data);
std::vector<KeyRange> partitions = co_await calculateBackupPartitionKeyRanges(&shards);
ASSERT(partitions.size() == 1);
ASSERT(partitions[0].begin == normalKeys.begin);
ASSERT(partitions[0].end == normalKeys.end);
}
TEST_CASE("/BackupPartitionMap/calculateBackupPartitionKeyRanges/VaryingSizes") {
ShardTrackedData defaultData;
defaultData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>();
KeyRangeMap<ShardTrackedData> shards(defaultData);
Key key1 = "a"_sr;
Key key2 = "b"_sr;
Key key3 = "c"_sr;
Key key4 = normalKeys.end;
std::vector<std::pair<KeyRange, int64_t>> testShards = { { KeyRangeRef(normalKeys.begin, key1), 50000 },
{ KeyRangeRef(key1, key2), 200000 },
{ KeyRangeRef(key2, key3), 10000 },
{ KeyRangeRef(key3, key4), 90000 } };
for (const auto& [range, bytes] : testShards) {
ShardTrackedData data;
StorageMetrics metrics;
metrics.bytes = bytes;
ShardMetrics shardMetrics(metrics, 0.0, 1);
data.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(shardMetrics);
shards.insert(range, data);
}
std::vector<KeyRange> partitions = co_await calculateBackupPartitionKeyRanges(&shards);
ASSERT(partitions.size() == 4);
ASSERT(partitions[0].begin == normalKeys.begin);
ASSERT(partitions[0].end == key1);
ASSERT(partitions[1].begin == key1);
ASSERT(partitions[1].end == key2);
ASSERT(partitions[2].begin == key2);
ASSERT(partitions[2].end == key3);
ASSERT(partitions[3].begin == key3);
ASSERT(partitions[3].end == key4);
}
TEST_CASE("/BackupPartitionMap/calculateBackupPartitionKeyRanges/ZeroSizeShards") {
ShardTrackedData defaultData;
defaultData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>();
KeyRangeMap<ShardTrackedData> shards(defaultData);
Key key1 = "a"_sr;
Key key2 = "b"_sr;
Key key3 = normalKeys.end;
std::vector<std::pair<KeyRange, int64_t>> testShards = { { KeyRangeRef(normalKeys.begin, key1), 0 },
{ KeyRangeRef(key1, key2), 1000000 },
{ KeyRangeRef(key2, key3), 0 } };
for (const auto& [range, bytes] : testShards) {
ShardTrackedData data;
StorageMetrics metrics;
metrics.bytes = bytes;
ShardMetrics shardMetrics(metrics, 0.0, 1);
data.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(shardMetrics);
shards.insert(range, data);
}
std::vector<KeyRange> partitions = co_await calculateBackupPartitionKeyRanges(&shards);
ASSERT(partitions.size() == 2);
ASSERT(partitions[0].begin == normalKeys.begin);
ASSERT(partitions[0].end == key2);
ASSERT(partitions[1].begin == key2);
ASSERT(partitions[1].end == normalKeys.end);
}
Future<Void> testAsyncMetricsUpdate() {
ShardTrackedData defaultData;
defaultData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>();
KeyRangeMap<ShardTrackedData> shards(defaultData);
Key splitKey = "split"_sr;
ShardTrackedData emptyData;
emptyData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>();
shards.insert(KeyRangeRef(normalKeys.begin, splitKey), emptyData);
ShardTrackedData dataWithMetrics;
StorageMetrics metrics;
metrics.bytes = 100000;
ShardMetrics shardMetrics(metrics, 0.0, 1);
dataWithMetrics.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(shardMetrics);
shards.insert(KeyRangeRef(splitKey, normalKeys.end), dataWithMetrics);
Future<std::vector<KeyRange>> resultFuture = calculateBackupPartitionKeyRanges(&shards);
co_await delay(0.1);
ASSERT(!resultFuture.isReady());
StorageMetrics newMetrics;
newMetrics.bytes = 50000;
ShardMetrics newShardMetrics(newMetrics, 0.0, 1);
shards.rangeContaining(normalKeys.begin)->value().stats->set(newShardMetrics);
std::vector<KeyRange> partitions = co_await resultFuture;
ASSERT(partitions.size() == 2);
ASSERT(partitions[0].begin == normalKeys.begin);
ASSERT(partitions[0].end == splitKey);
ASSERT(partitions[1].begin == splitKey);
ASSERT(partitions[1].end == normalKeys.end);
}
TEST_CASE("/BackupPartitionMap/calculateBackupPartitionKeyRanges/WaitForAsyncMetrics") {
co_await testAsyncMetricsUpdate();
}
TEST_CASE("/BackupPartitionMap/calculateBackupPartitionKeyRanges/MultipleSmallShards") {
ShardTrackedData defaultData;
StorageMetrics defaultMetrics;
defaultMetrics.bytes = 0;
ShardMetrics defaultShardMetrics(defaultMetrics, 0.0, 0);
defaultData.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(defaultShardMetrics);
KeyRangeMap<ShardTrackedData> shards(defaultData);
for (int i = 0; i < 1000; i++) {
Key start = Key(format("shard%04d", i));
Key end = (i == 999) ? normalKeys.end : Key(format("shard%04d", i + 1));
ShardTrackedData data;
StorageMetrics metrics;
metrics.bytes = 1000;
ShardMetrics shardMetrics(metrics, 0.0, 1);
data.stats = makeReference<AsyncVar<Optional<ShardMetrics>>>(shardMetrics);
shards.insert(KeyRangeRef(start, end), data);
}
std::vector<KeyRange> partitions = co_await calculateBackupPartitionKeyRanges(&shards);
ASSERT(partitions.size() == 100);
ASSERT(partitions[0].begin == normalKeys.begin);
ASSERT(partitions[partitions.size() - 1].end == normalKeys.end);
for (int i = 1; i < partitions.size(); i++) {
ASSERT(partitions[i - 1].end == partitions[i].begin);
}
}