fcb8d040e8
Instead of lengthy blurbs, switch to single-line, machine-readable standardized (https://spdx.dev) license identifiers. The Linux kernel switched long ago, so there is strong precedent. Three cases are handled: AGPL-only, Apache-only, and dual licensed. For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0), reasoning that our changes are extensive enough to apply our license. The changes we applied mechanically with a script, except to licenses/README.md. Closes #9937
77 lines
2.7 KiB
C++
77 lines
2.7 KiB
C++
/*
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* Copyright (C) 2018-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*/
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#pragma once
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#include "gc_clock.hh"
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#include "timestamp.hh"
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#include "utils/extremum_tracking.hh"
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// Stores statistics on all the updates done to a memtable
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// The collected statistics are used for flushing memtable to the disk
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struct encoding_stats {
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// The fixed epoch corresponds to the one used by Origin - 22/09/2015, 00:00:00, GMT-0:
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// Calendar c = Calendar.getInstance(TimeZone.getTimeZone("GMT-0"), Locale.US);
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// c.set(Calendar.YEAR, 2015);
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// c.set(Calendar.MONTH, Calendar.SEPTEMBER);
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// c.set(Calendar.DAY_OF_MONTH, 22);
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// c.set(Calendar.HOUR_OF_DAY, 0);
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// c.set(Calendar.MINUTE, 0);
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// c.set(Calendar.SECOND, 0);
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// c.set(Calendar.MILLISECOND, 0);
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//
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// long TIMESTAMP_EPOCH = c.getTimeInMillis() * 1000; // timestamps should be in microseconds by convention
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// int DELETION_TIME_EPOCH = (int)(c.getTimeInMillis() / 1000); // local deletion times are in seconds
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// Encoding stats are used for delta-encoding, so we want some default values
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// that are just good enough so we take some recent date in the past
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static constexpr int32_t deletion_time_epoch = 1442880000;
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static constexpr api::timestamp_type timestamp_epoch = api::timestamp_type(deletion_time_epoch) * 1000 * 1000;
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static constexpr int32_t ttl_epoch = 0;
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api::timestamp_type min_timestamp = timestamp_epoch;
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gc_clock::time_point min_local_deletion_time = gc_clock::time_point(gc_clock::duration(deletion_time_epoch));
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gc_clock::duration min_ttl = gc_clock::duration(ttl_epoch);
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};
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class encoding_stats_collector {
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private:
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min_tracker<api::timestamp_type> min_timestamp;
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min_tracker<gc_clock::time_point> min_local_deletion_time;
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min_tracker<gc_clock::duration> min_ttl;
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public:
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encoding_stats_collector()
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: min_timestamp(api::max_timestamp)
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, min_local_deletion_time(gc_clock::time_point::max())
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, min_ttl(gc_clock::duration::max())
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{}
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void update_timestamp(api::timestamp_type ts) {
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min_timestamp.update(ts);
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}
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void update_local_deletion_time(gc_clock::time_point local_deletion_time) {
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min_local_deletion_time.update(local_deletion_time);
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}
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void update_ttl(gc_clock::duration ttl) {
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min_ttl.update(ttl);
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}
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void update(const encoding_stats& other) {
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update_timestamp(other.min_timestamp);
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update_local_deletion_time(other.min_local_deletion_time);
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update_ttl(other.min_ttl);
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}
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encoding_stats get() const {
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return { min_timestamp.get(), min_local_deletion_time.get(), min_ttl.get() };
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}
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};
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