1d483bc424
When compacting several sstables, get and merge their encoding_stats for encoding the result. Introduce sstable::get_encoding_stats_for_compaction to return encoding_stats based on the sstable's column stats. Use encoding_stats_collector to keep track of the minimum encoding_stats values of all input sstables. Fixes #3971 Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
89 lines
3.2 KiB
C++
89 lines
3.2 KiB
C++
/*
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* Copyright (C) 2018 ScyllaDB
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*/
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/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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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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int32_t min_local_deletion_time = deletion_time_epoch;
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int32_t min_ttl = 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<int32_t> min_local_deletion_time;
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min_tracker<int32_t> 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(std::numeric_limits<int32_t>::max())
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, min_ttl(std::numeric_limits<int32_t>::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(int32_t 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(int32_t 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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