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Diffstat (limited to '')
-rw-r--r-- | src/rocksdb/db/blob/blob_garbage_meter.h | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/rocksdb/db/blob/blob_garbage_meter.h b/src/rocksdb/db/blob/blob_garbage_meter.h new file mode 100644 index 000000000..a6c04b0b2 --- /dev/null +++ b/src/rocksdb/db/blob/blob_garbage_meter.h @@ -0,0 +1,102 @@ +// Copyright (c) 2011-present, Facebook, Inc. All rights reserved. +// This source code is licensed under both the GPLv2 (found in the +// COPYING file in the root directory) and Apache 2.0 License +// (found in the LICENSE.Apache file in the root directory). + +#pragma once + +#include <cassert> +#include <cstdint> +#include <unordered_map> + +#include "db/blob/blob_constants.h" +#include "rocksdb/rocksdb_namespace.h" +#include "rocksdb/status.h" + +namespace ROCKSDB_NAMESPACE { + +class Slice; + +// A class that can be used to compute the amount of additional garbage +// generated by a compaction. It parses the keys and blob references in the +// input and output of a compaction, and aggregates the "inflow" and "outflow" +// on a per-blob file basis. The amount of additional garbage for any given blob +// file can then be computed by subtracting the outflow from the inflow. +class BlobGarbageMeter { + public: + // A class to store the number and total size of blobs on a per-blob file + // basis. + class BlobStats { + public: + void Add(uint64_t bytes) { + ++count_; + bytes_ += bytes; + } + void Add(uint64_t count, uint64_t bytes) { + count_ += count; + bytes_ += bytes; + } + + uint64_t GetCount() const { return count_; } + uint64_t GetBytes() const { return bytes_; } + + private: + uint64_t count_ = 0; + uint64_t bytes_ = 0; + }; + + // A class to keep track of the "inflow" and the "outflow" and to compute the + // amount of additional garbage for a given blob file. + class BlobInOutFlow { + public: + void AddInFlow(uint64_t bytes) { + in_flow_.Add(bytes); + assert(IsValid()); + } + void AddOutFlow(uint64_t bytes) { + out_flow_.Add(bytes); + assert(IsValid()); + } + + const BlobStats& GetInFlow() const { return in_flow_; } + const BlobStats& GetOutFlow() const { return out_flow_; } + + bool IsValid() const { + return in_flow_.GetCount() >= out_flow_.GetCount() && + in_flow_.GetBytes() >= out_flow_.GetBytes(); + } + bool HasGarbage() const { + assert(IsValid()); + return in_flow_.GetCount() > out_flow_.GetCount(); + } + uint64_t GetGarbageCount() const { + assert(IsValid()); + assert(HasGarbage()); + return in_flow_.GetCount() - out_flow_.GetCount(); + } + uint64_t GetGarbageBytes() const { + assert(IsValid()); + assert(HasGarbage()); + return in_flow_.GetBytes() - out_flow_.GetBytes(); + } + + private: + BlobStats in_flow_; + BlobStats out_flow_; + }; + + Status ProcessInFlow(const Slice& key, const Slice& value); + Status ProcessOutFlow(const Slice& key, const Slice& value); + + const std::unordered_map<uint64_t, BlobInOutFlow>& flows() const { + return flows_; + } + + private: + static Status Parse(const Slice& key, const Slice& value, + uint64_t* blob_file_number, uint64_t* bytes); + + std::unordered_map<uint64_t, BlobInOutFlow> flows_; +}; + +} // namespace ROCKSDB_NAMESPACE |