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-rw-r--r--src/mongo/db/s/balancer/balancer_policy.h140
1 files changed, 97 insertions, 43 deletions
diff --git a/src/mongo/db/s/balancer/balancer_policy.h b/src/mongo/db/s/balancer/balancer_policy.h
index 008c1d93b7e..e2be0a50f47 100644
--- a/src/mongo/db/s/balancer/balancer_policy.h
+++ b/src/mongo/db/s/balancer/balancer_policy.h
@@ -59,16 +59,18 @@ struct MigrateInfo {
MigrateInfo(const ShardId& a_to,
const NamespaceString& a_nss,
const ChunkType& a_chunk,
- MoveChunkRequest::ForceJumbo a_forceJumbo);
+ MoveChunkRequest::ForceJumbo a_forceJumbo,
+ boost::optional<int64_t> maxChunkSizeBytes = boost::none);
MigrateInfo(const ShardId& a_to,
const ShardId& a_from,
const NamespaceString& a_nss,
const UUID& a_uuid,
const BSONObj& a_min,
- const BSONObj& a_max,
+ const boost::optional<BSONObj>& a_max,
const ChunkVersion& a_version,
- MoveChunkRequest::ForceJumbo a_forceJumbo);
+ MoveChunkRequest::ForceJumbo a_forceJumbo,
+ boost::optional<int64_t> maxChunkSizeBytes = boost::none);
std::string getName() const;
@@ -76,14 +78,22 @@ struct MigrateInfo {
std::string toString() const;
+ boost::optional<int64_t> getMaxChunkSizeBytes() const;
+
NamespaceString nss;
UUID uuid;
ShardId to;
ShardId from;
BSONObj minKey;
- BSONObj maxKey;
+
+ // May be optional in case of moveRange
+ boost::optional<BSONObj> maxKey;
ChunkVersion version;
MoveChunkRequest::ForceJumbo forceJumbo;
+
+ // Set only in case of data-size aware balancing
+ // TODO SERVER-65322 make `optMaxChunkSizeBytes` non-optional
+ boost::optional<int64_t> optMaxChunkSizeBytes;
};
enum MigrationReason { none, drain, zoneViolation, chunksImbalance };
@@ -176,7 +186,8 @@ struct DataSizeInfo {
const ChunkRange& chunkRange,
const ChunkVersion& version,
const KeyPattern& keyPattern,
- bool estimatedValue);
+ bool estimatedValue,
+ int64_t maxSize);
ShardId shardId;
NamespaceString nss;
@@ -185,14 +196,16 @@ struct DataSizeInfo {
ChunkVersion version;
KeyPattern keyPattern;
bool estimatedValue;
+ int64_t maxSize;
};
struct DataSizeResponse {
- DataSizeResponse(long long sizeBytes, long long numObjects)
- : sizeBytes(sizeBytes), numObjects(numObjects) {}
+ DataSizeResponse(long long sizeBytes, long long numObjects, bool maxSizeReached)
+ : sizeBytes(sizeBytes), numObjects(numObjects), maxSizeReached(maxSizeReached) {}
long long sizeBytes;
long long numObjects;
+ bool maxSizeReached;
};
typedef stdx::
@@ -205,6 +218,18 @@ typedef stdx::variant<Status, StatusWith<AutoSplitVectorResponse>, StatusWith<Da
typedef std::vector<ClusterStatistics::ShardStatistics> ShardStatisticsVector;
typedef std::map<ShardId, std::vector<ChunkType>> ShardToChunksMap;
+/*
+ * Keeps track of info needed for data size aware balancing.
+ */
+struct CollectionDataSizeInfoForBalancing {
+ CollectionDataSizeInfoForBalancing(std::map<ShardId, int64_t>&& shardToDataSizeMap,
+ long maxChunkSizeBytes)
+ : shardToDataSizeMap(std::move(shardToDataSizeMap)), maxChunkSizeBytes(maxChunkSizeBytes) {}
+
+ std::map<ShardId, int64_t> shardToDataSizeMap;
+ const int64_t maxChunkSizeBytes;
+};
+
/**
* Keeps track of zones for a collection.
*/
@@ -364,24 +389,26 @@ public:
const std::string& chunkTag);
/**
- * Returns a suggested set of chunks to move whithin a collection's shards, given the specified
- * state of the shards (draining, max size reached, etc) and the number of chunks for that
- * collection. If the policy doesn't recommend anything to move, it returns an empty vector. The
- * entries in the vector do are all for separate source/destination shards and as such do not
- * need to be done serially and can be scheduled in parallel.
+ * Returns a suggested set of chunks or ranges to move within a collection's shards, given the
+ * specified state of the shards (draining, max size reached, etc) and the number of chunks or
+ * data size for that collection. If the policy doesn't recommend anything to move, it returns
+ * an empty vector. The entries in the vector do are all for separate source/destination shards
+ * and as such do not need to be done serially and can be scheduled in parallel.
*
* The balancing logic calculates the optimum number of chunks per shard for each zone and if
* any of the shards have chunks, which are sufficiently higher than this number, suggests
* moving chunks to shards, which are under this number.
*
- * The usedShards parameter is in/out and it contains the set of shards, which have already been
- * used for migrations. Used so we don't return multiple conflicting migrations for the same
- * shard.
+ * The availableShards parameter is in/out and it contains the set of shards, which haven't
+ * been used for migrations yet. Used so we don't return multiple conflicting migrations for the
+ * same shard.
*/
- static MigrateInfosWithReason balance(const ShardStatisticsVector& shardStats,
- const DistributionStatus& distribution,
- stdx::unordered_set<ShardId>* usedShards,
- bool forceJumbo);
+ static MigrateInfosWithReason balance(
+ const ShardStatisticsVector& shardStats,
+ const DistributionStatus& distribution,
+ const boost::optional<CollectionDataSizeInfoForBalancing>& collDataSizeInfo,
+ stdx::unordered_set<ShardId>* availableShards,
+ bool forceJumbo);
/**
* Using the specified distribution information, returns a suggested better location for the
@@ -392,43 +419,70 @@ public:
const DistributionStatus& distribution);
private:
- /**
- * Return the shard with the specified tag, which has the least number of chunks. If the tag is
- * empty, considers all shards.
+ /*
+ * Only considers shards with the specified tag, all shards in case the tag is empty.
+ *
+ * Returns a tuple <ShardID, number of chunks> referring the shard with less chunks.
+ *
+ * If balancing based on collection size on shards:
+ * - Returns a tuple <ShardID, amount of data in bytes> referring the shard with less data.
*/
- static ShardId _getLeastLoadedReceiverShard(const ShardStatisticsVector& shardStats,
- const DistributionStatus& distribution,
- const std::string& tag,
- const stdx::unordered_set<ShardId>& excludedShards);
+ static std::tuple<ShardId, int64_t> _getLeastLoadedReceiverShard(
+ const ShardStatisticsVector& shardStats,
+ const DistributionStatus& distribution,
+ const boost::optional<CollectionDataSizeInfoForBalancing>& collDataSizeInfo,
+ const std::string& tag,
+ const stdx::unordered_set<ShardId>& availableShards);
/**
- * Return the shard which has the least number of chunks with the specified tag. If the tag is
- * empty, considers all chunks.
+ * Only considers shards with the specified tag, all shards in case the tag is empty.
+ *
+ * If balancing based on number of chunks:
+ * - Returns a tuple <ShardID, number of chunks> referring the shard with more chunks.
+ *
+ * If balancing based on collection size on shards:
+ * - Returns a tuple <ShardID, amount of data in bytes> referring the shard with more data.
*/
- static ShardId _getMostOverloadedShard(const ShardStatisticsVector& shardStats,
- const DistributionStatus& distribution,
- const std::string& chunkTag,
- const stdx::unordered_set<ShardId>& excludedShards);
+ static std::tuple<ShardId, int64_t> _getMostOverloadedShard(
+ const ShardStatisticsVector& shardStats,
+ const DistributionStatus& distribution,
+ const boost::optional<CollectionDataSizeInfoForBalancing>& collDataSizeInfo,
+ const std::string& chunkTag,
+ const stdx::unordered_set<ShardId>& availableShards);
/**
* Selects one chunk for the specified zone (if appropriate) to be moved in order to bring the
* deviation of the shards chunk contents closer to even across all shards in the specified
- * zone. Takes into account and updates the shards, which have already been used for migrations.
+ * zone. Takes into account and updates the shards, which haven't been used for migrations yet.
*
- * The 'idealNumberOfChunksPerShardForTag' indicates what is the ideal number of chunks which
- * each shard must have and is used to determine the imbalance and also to prevent chunks from
- * moving when not necessary.
+ * Returns true if a migration was suggested, false otherwise. This method is intented to be
+ * called multiple times until all posible migrations for a zone have been selected.
+ */
+ static bool _singleZoneBalanceBasedOnChunks(const ShardStatisticsVector& shardStats,
+ const DistributionStatus& distribution,
+ const std::string& tag,
+ size_t totalNumberOfShardsWithTag,
+ std::vector<MigrateInfo>* migrations,
+ stdx::unordered_set<ShardId>* availableShards,
+ MoveChunkRequest::ForceJumbo forceJumbo);
+
+ /**
+ * Selects one range for the specified zone (if appropriate) to be moved in order to bring the
+ * deviation of the collection data size closer to even across all shards in the specified
+ * zone. Takes into account and updates the shards, which haven't been used for migrations yet.
*
* Returns true if a migration was suggested, false otherwise. This method is intented to be
* called multiple times until all posible migrations for a zone have been selected.
*/
- static bool _singleZoneBalance(const ShardStatisticsVector& shardStats,
- const DistributionStatus& distribution,
- const std::string& tag,
- size_t idealNumberOfChunksPerShardForTag,
- std::vector<MigrateInfo>* migrations,
- stdx::unordered_set<ShardId>* usedShards,
- MoveChunkRequest::ForceJumbo forceJumbo);
+ static bool _singleZoneBalanceBasedOnDataSize(
+ const ShardStatisticsVector& shardStats,
+ const DistributionStatus& distribution,
+ const CollectionDataSizeInfoForBalancing& collDataSizeInfo,
+ const std::string& tag,
+ int64_t idealDataSizePerShardForZone,
+ std::vector<MigrateInfo>* migrations,
+ stdx::unordered_set<ShardId>* availableShards,
+ MoveChunkRequest::ForceJumbo forceJumbo);
};
} // namespace mongo
generated by cgit v1.2.3 (git 2.39.1) at 2026-09-11 10:42:33 +0000