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42 lines
904 B
C++
42 lines
904 B
C++
#pragma once
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#include <memory>
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#include <ctime>
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#include <cstddef>
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namespace DB
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{
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class Context;
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class BackgroundProcessingPool;
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class BackgroundProcessingPoolTaskInfo;
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/// Add a task to BackgroundProcessingPool that watch for ProfileEvents::NetworkErrors and updates DNS cache if it has increased
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class DNSCacheUpdater
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{
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public:
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explicit DNSCacheUpdater(Context & context);
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~DNSCacheUpdater();
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/// Checks if it is a network error and increments ProfileEvents::NetworkErrors
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static bool incrementNetworkErrorEventsIfNeeded();
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private:
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bool run();
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Context & context;
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BackgroundProcessingPool & pool;
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std::shared_ptr<BackgroundProcessingPoolTaskInfo> task_handle;
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size_t last_num_network_erros = 0;
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time_t last_update_time = 0;
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static constexpr size_t min_errors_to_update_cache = 3;
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static constexpr time_t min_update_period_seconds = 45;
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};
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}
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