d87d50dc64
Currently server-side timestamps use a clock with millisecond precision. Timestamps have microsecond resolution, with lower bits used to serialize mutations originating from given client. Timestamps for column drops always use just the millisecond base. A column drop which is executed after an insert may thus be given lower timestamp than the insert, even when the two are serialized on the client side over same connection. Use microsecond precision to reduce chances of that event. This is supposed to fix sporadic failures of schema_test.py:TestSchema.drop_column_queries_test dtest. Message-Id: <1482343119-27698-1-git-send-email-tgrabiec@scylladb.com>
59 lines
2.0 KiB
C++
59 lines
2.0 KiB
C++
/*
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* Copyright (C) 2014 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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#ifndef DB_CLOCK_HH_
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#define DB_CLOCK_HH_
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#include <chrono>
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#include <cstdint>
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#include "gc_clock.hh"
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// the database clock follows Java - 1ms granularity, 64-bit counter, 1970 epoch
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class db_clock {
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public:
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using base = std::chrono::system_clock;
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using rep = int64_t;
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using period = std::ratio<1, 1000>; // milliseconds
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using duration = std::chrono::duration<rep, period>;
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using time_point = std::chrono::time_point<db_clock, duration>;
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static constexpr bool is_steady = base::is_steady;
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static std::time_t to_time_t(time_point t) {
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return std::chrono::duration_cast<std::chrono::seconds>(t.time_since_epoch()).count();
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}
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static time_point from_time_t(std::time_t t) {
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return time_point(std::chrono::duration_cast<duration>(std::chrono::seconds(t)));
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}
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static time_point now() {
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auto now_since_epoch = base::now() - base::from_time_t(0);
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return time_point(std::chrono::duration_cast<duration>(now_since_epoch)) + get_clocks_offset();
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}
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};
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static inline
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gc_clock::time_point to_gc_clock(db_clock::time_point tp) {
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static_assert(std::is_same<db_clock::base, gc_clock::base>::value, "Below we assume that base is the same");
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return gc_clock::time_point(std::chrono::duration_cast<gc_clock::duration>(tp.time_since_epoch()));
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}
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#endif /* DB_CLOCK_HH_ */
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