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1a9c6d9fd3
This patch implements a simple variation of LFRU eviction policy:
* We define 2 dynamic cache sections which total size should not exceed the maximum cache size.
* New cache entry is always added to the "unprivileged" section.
* After a cache entry is read more than SectionHitThreshold times it moves to the second cache section.
* Both sections' entries obey expiration and reload rules in the same way as before this patch.
* When cache entries need to be evicted due to a size restriction "unprivileged" section's
least recently used entries are evicted first.
Note:
With a 2 sections cache it's not enough for a new entry to have the latest timestamp
in order not be evicted right after insertion: e.g. if all all other entries
are from the privileged section.
And obviously we want to allow new cache entries to be added to a cache.
Therefore we can no longer first add a new entry and then shrink the cache.
Switching the order of these two operations resolves the culprit.
Fixes #8674
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
47 lines
1.5 KiB
C++
47 lines
1.5 KiB
C++
/*
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* Copyright 2019-present 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 Affero 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 <string>
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#include <string_view>
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#include <array>
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#include "gc_clock.hh"
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#include "utils/loading_cache.hh"
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namespace service {
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class storage_proxy;
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}
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namespace alternator {
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using hmac_sha256_digest = std::array<char, 32>;
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using key_cache = utils::loading_cache<std::string, std::string, 1>;
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std::string get_signature(std::string_view access_key_id, std::string_view secret_access_key, std::string_view host, std::string_view method,
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std::string_view orig_datestamp, std::string_view signed_headers_str, const std::map<std::string_view, std::string_view>& signed_headers_map,
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const std::vector<temporary_buffer<char>>& body_content, std::string_view region, std::string_view service, std::string_view query_string);
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future<std::string> get_key_from_roles(service::storage_proxy& proxy, std::string username);
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}
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