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Translated comments [#CLICKHOUSE-2].

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This commit is contained in:
Alexey Milovidov 2017-07-27 23:22:53 +03:00
parent 9bb647d5d5
commit c477c7e1cb
2 changed files with 27 additions and 27 deletions
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39
libs/libmysqlxx/include/mysqlxx/PoolWithFailover.h
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@ -3,18 +3,19 @@
#include "Pool.h"
#define MYSQLXX_POOL_WITH_FAILOVER_DEFAULT_START_CONNECTIONS 1
#define MYSQLXX_POOL_WITH_FAILOVER_DEFAULT_MAX_CONNECTIONS 16
#define MYSQLXX_POOL_WITH_FAILOVER_DEFAULT_MAX_TRIES 3
#define MYSQLXX_POOL_WITH_FAILOVER_DEFAULT_START_CONNECTIONS 1
#define MYSQLXX_POOL_WITH_FAILOVER_DEFAULT_MAX_CONNECTIONS 16
#define MYSQLXX_POOL_WITH_FAILOVER_DEFAULT_MAX_TRIES 3
namespace mysqlxx
{
/** Пул соединений с MySQL.
* Знает о наборе реплик с приоритетами.
* Пробует соединяться с репликами в порядке приоритета. При равном приоритете предпочитается реплика, к которой дольше всего не было попытки подключения.
/** MySQL connection pool with support of failover.
* Have information about replicas and their priorities.
* Tries to connect to replica in an order of priority. When equal priority, choose replica with maximum time without connections.
*
* It could be configured without replicas, exactly as ordinary Pool:
*
* Использование аналогично mysqlxx::Pool. В конфиге задание сервера может выглядеть так же, как для Pool:
* <mysql_metrica>
* <host>mtstat01c*</host>
* <port>3306</port>
@ -23,7 +24,7 @@ namespace mysqlxx
* <db>Metrica</db>
* </mysql_metrica>
*
* или так:
* Or like this:
*
* <mysql_metrica>
* <replica>
@ -44,14 +45,14 @@ namespace mysqlxx
* </replica>
* </mysql_metrica>
*
* или так:
* Or like this:
*
* <mysql_metrica>
* <port>3306</port>
* <port>3306</port>
* <user>metrica</user>
* <password></password>
* <db>Metrica</db>
* <replica>
* <replica>
* <host>mtstat01c</host>
* <priority>0</priority>
* </replica>
@ -78,24 +79,24 @@ namespace mysqlxx
};
using Replicas = std::vector<Replica>;
/// [приоритет][номер] -> реплика.
/// [priority][index] -> replica.
using ReplicasByPriority = std::map<int, Replicas>;
ReplicasByPriority replicas_by_priority;
/// Количество попыток подключения.
/// Number of connection tries.
size_t max_tries;
/// Mutex для доступа к списку реплик.
/// Mutex for set of replicas.
std::mutex mutex;
public:
using Entry = Pool::Entry;
/**
* @param config_name Имя параметра в конфигурационном файле.
* @param default_connections Количество подключений по умолчанию к какждой реплике.
* @param max_connections Максимальное количество подключений к какждой реплике.
* @param max_tries_ Количество попыток подключения.
* config_name Name of parameter in configuration file.
* default_connections Number of connection in pool to each replica at start.
* max_connections Maximum number of connections in pool to each replica.
* max_tries_ Max number of connection tries.
*/
PoolWithFailover(const std::string & config_name,
unsigned default_connections = MYSQLXX_POOL_WITH_FAILOVER_DEFAULT_START_CONNECTIONS,
@ -112,7 +113,7 @@ namespace mysqlxx
PoolWithFailover & operator=(const PoolWithFailover &) = delete;
/** Выделяет соединение для работы. */
/** Allocates a connection to use. */
Entry Get();
};
}

15
libs/libmysqlxx/src/PoolWithFailover.cpp
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@ -13,11 +13,11 @@ PoolWithFailover::PoolWithFailover(const Poco::Util::AbstractConfiguration & cfg
{
Poco::Util::AbstractConfiguration::Keys replica_keys;
cfg.keys(config_name, replica_keys);
for (Poco::Util::AbstractConfiguration::Keys::const_iterator it = replica_keys.begin(); it != replica_keys.end(); ++it)
for (const auto & replica_config_key : replica_keys)
{
if (*it == "replica") /// На том же уровне могут быть другие параметры.
if (replica_config_key == "replica") /// There could be another elements in the same level in configuration file.
{
std::string replica_name = config_name + "." + *it;
std::string replica_name = config_name + "." + replica_config_key;
Replica replica(std::make_shared<Pool>(cfg, replica_name, default_connections, max_connections, config_name.c_str()),
cfg.getInt(replica_name + ".priority", 0));
replicas_by_priority[replica.priority].push_back(replica);
@ -34,8 +34,7 @@ PoolWithFailover::PoolWithFailover(const std::string & config_name, const unsign
const unsigned max_connections, const size_t max_tries)
: PoolWithFailover{
Poco::Util::Application::instance().config(), config_name,
default_connections, max_connections, max_tries
}
default_connections, max_connections, max_tries}
{}
PoolWithFailover::PoolWithFailover(const PoolWithFailover & other)
@ -56,7 +55,7 @@ PoolWithFailover::Entry PoolWithFailover::Get()
std::lock_guard<std::mutex> locker(mutex);
Poco::Util::Application & app = Poco::Util::Application::instance();
/// Если к какой-то реплике не подключились, потому что исчерпан лимит соединений, можно подождать и подключиться к ней.
/// If we cannot connect to some replica due to pool overflow, than we will wait and connect.
Replica * full_pool = nullptr;
for (size_t try_no = 0; try_no < max_tries; ++try_no)
@ -76,8 +75,8 @@ PoolWithFailover::Entry PoolWithFailover::Get()
if (!entry.isNull())
{
/// Переместим все пройденные реплики в конец очереди.
/// Пройденные реплики с другим приоритетом перемещать незачем.
/// Move all traversed replicas to the end of queue.
/// (No need to move replicas with another priority)
std::rotate(replicas.begin(), replicas.begin() + i + 1, replicas.end());
return entry;