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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
commit | e6918187568dbd01842d8d1d2c808ce16a894239 (patch) | |
tree | 64f88b554b444a49f656b6c656111a145cbbaa28 /src/rocksdb/db/compaction/file_pri.h | |
parent | Initial commit. (diff) | |
download | ceph-e6918187568dbd01842d8d1d2c808ce16a894239.tar.xz ceph-e6918187568dbd01842d8d1d2c808ce16a894239.zip |
Adding upstream version 18.2.2.upstream/18.2.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/rocksdb/db/compaction/file_pri.h | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/src/rocksdb/db/compaction/file_pri.h b/src/rocksdb/db/compaction/file_pri.h new file mode 100644 index 000000000..82dddcf93 --- /dev/null +++ b/src/rocksdb/db/compaction/file_pri.h @@ -0,0 +1,92 @@ +// 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 <algorithm> + +#include "db/version_edit.h" + +namespace ROCKSDB_NAMESPACE { +// We boost files that are closer to TTL limit. This boosting could be +// through FileMetaData.compensated_file_size but this compensated size +// is widely used as something similar to file size so dramatically boost +// the value might cause unintended consequences. +// +// This boosting algorithm can go very fancy, but here we use a simple +// formula which can satisify: +// (1) Different levels are triggered slightly differently to avoid +// too many cascading cases +// (2) Files in the same level get boosting more when TTL gets closer. +// +// Don't do any boosting before TTL has past by half. This is to make +// sure lower write amp for most of the case. And all levels should be +// fully boosted when total TTL compaction threshold triggers. +// Differientiate boosting ranges of each level by 1/2. This will make +// range for each level exponentially increasing. We could do it by +// having them to be equal, or go even fancier. We can adjust it after +// we observe the behavior in production. +// The threshold starting boosting: +// +------------------------------------------------------------------ + +// ^ ^ ^ ^ ^ ^ +// Age 0 ... | | second last level thresold +// | | +// | third last level +// | +// forth last level +// +// We arbitrarily set with 0 when a file is aged boost_age_start and +// grow linearly. The ratio is arbitrarily set so that when the next level +// starts to boost, the previous level's boosting amount is 16. +class FileTtlBooster { + public: + FileTtlBooster(uint64_t current_time, uint64_t ttl, int num_non_empty_levels, + int level) + : current_time_(current_time) { + if (ttl == 0 || level == 0 || level >= num_non_empty_levels - 1) { + enabled_ = false; + boost_age_start_ = 0; + boost_step_ = 1; + } else { + enabled_ = true; + uint64_t all_boost_start_age = ttl / 2; + uint64_t all_boost_age_range = (ttl / 32) * 31 - all_boost_start_age; + uint64_t boost_age_range = + all_boost_age_range >> (num_non_empty_levels - level - 1); + boost_age_start_ = all_boost_start_age + boost_age_range; + const uint64_t kBoostRatio = 16; + // prevent 0 value to avoid divide 0 error. + boost_step_ = std::max(boost_age_range / kBoostRatio, uint64_t{1}); + } + } + + uint64_t GetBoostScore(FileMetaData* f) { + if (!enabled_) { + return 1; + } + uint64_t oldest_ancester_time = f->TryGetOldestAncesterTime(); + if (oldest_ancester_time >= current_time_) { + return 1; + } + uint64_t age = current_time_ - oldest_ancester_time; + if (age > boost_age_start_) { + // Use integer just for convenience. + // We could make all file_to_order double if we want. + // Technically this can overflow if users override timing and + // give a very high current time. Ignore the case for simplicity. + // Boosting is addition to current value, so +1. This will effectively + // make boosting to kick in after the first boost_step_ is reached. + return (age - boost_age_start_) / boost_step_ + 1; + } + return 1; + } + + private: + bool enabled_; + uint64_t current_time_; + uint64_t boost_age_start_; + uint64_t boost_step_; +}; +} // namespace ROCKSDB_NAMESPACE |