ClickHouse/dbms/src/Interpreters/IExternalLoadable.cpp
2019-10-23 12:27:34 +03:00

37 lines
1.1 KiB
C++

#include <Interpreters/IExternalLoadable.h>
#include <Poco/Util/AbstractConfiguration.h>
#include <cmath>
namespace DB
{
ExternalLoadableLifetime::ExternalLoadableLifetime(const Poco::Util::AbstractConfiguration & config,
const std::string & config_prefix)
{
const auto & lifetime_min_key = config_prefix + ".min";
const auto has_min = config.has(lifetime_min_key);
min_sec = has_min ? config.getUInt64(lifetime_min_key) : config.getUInt64(config_prefix);
max_sec = has_min ? config.getUInt64(config_prefix + ".max") : min_sec;
}
UInt64 calculateDurationWithBackoff(pcg64 & rnd_engine, size_t error_count)
{
constexpr UInt64 backoff_initial_sec = 5;
constexpr UInt64 backoff_max_sec = 10 * 60; /// 10 minutes
if (error_count < 1)
error_count = 1;
/// max seconds is 600 and 2 ** 10 == 1024
if (error_count > 11)
error_count = 11;
std::uniform_int_distribution<UInt64> distribution(0, static_cast<UInt64>(std::exp2(error_count - 1)));
return std::min<UInt64>(backoff_max_sec, backoff_initial_sec + distribution(rnd_engine));
}
}