3b2a1ddd2e
Summary: If options.base_background_compactions is given, we try to schedule number of compactions not existing this number, only when L0 files increase to certain number, or pending compaction bytes more than certain threshold, we schedule compactions based on options.max_background_compactions. The watermarks are calculated based on slowdown thresholds. Test Plan: Add new test cases in column_family_test. Adding more unit tests. Reviewers: IslamAbdelRahman, yhchiang, kradhakrishnan, rven, anthony Reviewed By: anthony Subscribers: leveldb, dhruba, yoshinorim Differential Revision: https://reviews.facebook.net/D53409
116 lines
3.7 KiB
C++
116 lines
3.7 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once
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#include <stdint.h>
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#include <memory>
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namespace rocksdb {
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class Env;
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class WriteControllerToken;
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// WriteController is controlling write stalls in our write code-path. Write
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// stalls happen when compaction can't keep up with write rate.
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// All of the methods here (including WriteControllerToken's destructors) need
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// to be called while holding DB mutex
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class WriteController {
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public:
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explicit WriteController(uint64_t _delayed_write_rate = 1024u * 1024u * 32u)
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: total_stopped_(0),
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total_delayed_(0),
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total_compaction_pressure_(0),
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bytes_left_(0),
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last_refill_time_(0) {
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set_delayed_write_rate(_delayed_write_rate);
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}
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~WriteController() = default;
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// When an actor (column family) requests a stop token, all writes will be
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// stopped until the stop token is released (deleted)
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std::unique_ptr<WriteControllerToken> GetStopToken();
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// When an actor (column family) requests a delay token, total delay for all
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// writes to the DB will be controlled under the delayed write rate. Every
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// write needs to call GetDelay() with number of bytes writing to the DB,
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// which returns number of microseconds to sleep.
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std::unique_ptr<WriteControllerToken> GetDelayToken(
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uint64_t delayed_write_rate);
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// When an actor (column family) requests a moderate token, compaction
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// threads will be increased
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std::unique_ptr<WriteControllerToken> GetCompactionPressureToken();
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// these three metods are querying the state of the WriteController
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bool IsStopped() const;
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bool NeedsDelay() const { return total_delayed_ > 0; }
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bool NeedSpeedupCompaction() const {
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return IsStopped() || NeedsDelay() || total_compaction_pressure_ > 0;
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}
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// return how many microseconds the caller needs to sleep after the call
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// num_bytes: how many number of bytes to put into the DB.
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// Prerequisite: DB mutex held.
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uint64_t GetDelay(Env* env, uint64_t num_bytes);
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void set_delayed_write_rate(uint64_t write_rate) {
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// avoid divide 0
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if (write_rate == 0) {
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write_rate = 1u;
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}
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delayed_write_rate_ = write_rate;
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}
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uint64_t delayed_write_rate() const { return delayed_write_rate_; }
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private:
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friend class WriteControllerToken;
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friend class StopWriteToken;
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friend class DelayWriteToken;
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friend class CompactionPressureToken;
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int total_stopped_;
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int total_delayed_;
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int total_compaction_pressure_;
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uint64_t bytes_left_;
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uint64_t last_refill_time_;
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uint64_t delayed_write_rate_;
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};
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class WriteControllerToken {
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public:
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explicit WriteControllerToken(WriteController* controller)
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: controller_(controller) {}
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virtual ~WriteControllerToken() {}
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protected:
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WriteController* controller_;
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private:
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// no copying allowed
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WriteControllerToken(const WriteControllerToken&) = delete;
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void operator=(const WriteControllerToken&) = delete;
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};
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class StopWriteToken : public WriteControllerToken {
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public:
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explicit StopWriteToken(WriteController* controller)
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: WriteControllerToken(controller) {}
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virtual ~StopWriteToken();
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};
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class DelayWriteToken : public WriteControllerToken {
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public:
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explicit DelayWriteToken(WriteController* controller)
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: WriteControllerToken(controller) {}
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virtual ~DelayWriteToken();
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};
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class CompactionPressureToken : public WriteControllerToken {
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public:
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explicit CompactionPressureToken(WriteController* controller)
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: WriteControllerToken(controller) {}
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virtual ~CompactionPressureToken();
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};
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} // namespace rocksdb
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