ClickHouse/programs/odbc-bridge/ODBCPooledConnectionFactory.h

173 lines
4.7 KiB
C++

#pragma once
#include <Common/logger_useful.h>
#include <nanodbc/nanodbc.h>
#include <mutex>
#include <base/BorrowedObjectPool.h>
#include <unordered_map>
namespace DB
{
namespace ErrorCodes
{
extern const int NO_FREE_CONNECTION;
}
}
namespace nanodbc
{
using ConnectionPtr = std::unique_ptr<nanodbc::connection>;
using Pool = BorrowedObjectPool<ConnectionPtr>;
using PoolPtr = std::shared_ptr<Pool>;
static constexpr inline auto ODBC_CONNECT_TIMEOUT = 100;
class ConnectionHolder
{
public:
ConnectionHolder(PoolPtr pool_,
ConnectionPtr connection_,
const String & connection_string_)
: pool(pool_)
, connection(std::move(connection_))
, connection_string(connection_string_)
{
}
explicit ConnectionHolder(const String & connection_string_)
: pool(nullptr)
, connection()
, connection_string(connection_string_)
{
updateConnection();
}
ConnectionHolder(const ConnectionHolder & other) = delete;
~ConnectionHolder()
{
if (pool != nullptr)
pool->returnObject(std::move(connection));
}
nanodbc::connection & get() const
{
assert(connection != nullptr);
return *connection;
}
void updateConnection()
{
connection = std::make_unique<nanodbc::connection>(connection_string, ODBC_CONNECT_TIMEOUT);
}
private:
PoolPtr pool;
ConnectionPtr connection;
String connection_string;
};
using ConnectionHolderPtr = std::shared_ptr<ConnectionHolder>;
}
namespace DB
{
static constexpr inline auto ODBC_CONNECT_TIMEOUT = 100;
static constexpr inline auto ODBC_POOL_WAIT_TIMEOUT = 10000;
template <typename T>
T execute(nanodbc::ConnectionHolderPtr connection_holder, std::function<T(nanodbc::connection &)> query_func)
{
try
{
return query_func(connection_holder->get());
}
catch (const nanodbc::database_error & e)
{
tryLogCurrentException(__PRETTY_FUNCTION__);
/// SQLState, connection related errors start with 08 (main: 08S01), cursor invalid state is 24000.
/// Invalid cursor state is a retriable error.
/// Invalid transaction state 25000. Truncate to 2 letters on purpose.
/// https://docs.microsoft.com/ru-ru/sql/odbc/reference/appendixes/appendix-a-odbc-error-codes?view=sql-server-ver15
if (e.state().starts_with("08") || e.state().starts_with("24") || e.state().starts_with("25"))
{
connection_holder->updateConnection();
return query_func(connection_holder->get());
}
/// psqlodbc driver error handling is incomplete and under some scenarious
/// it doesn't propagate correct errors to the caller.
/// As a quick workaround we run a quick "ping" query over the connection
/// on generic errors.
/// If "ping" fails, recycle the connection and try the query once more.
if (e.state().starts_with("HY00"))
{
try
{
just_execute(connection_holder->get(), "SELECT 1");
}
catch (...)
{
connection_holder->updateConnection();
return query_func(connection_holder->get());
}
}
throw;
}
}
class ODBCPooledConnectionFactory final : private boost::noncopyable
{
public:
static ODBCPooledConnectionFactory & instance()
{
static ODBCPooledConnectionFactory ret;
return ret;
}
nanodbc::ConnectionHolderPtr get(const std::string & connection_string, size_t pool_size)
{
std::lock_guard lock(mutex);
if (!factory.count(connection_string))
factory.emplace(std::make_pair(connection_string, std::make_shared<nanodbc::Pool>(pool_size)));
auto & pool = factory[connection_string];
nanodbc::ConnectionPtr connection;
auto connection_available = pool->tryBorrowObject(connection, []() { return nullptr; }, ODBC_POOL_WAIT_TIMEOUT);
if (!connection_available)
throw Exception("Unable to fetch connection within the timeout", ErrorCodes::NO_FREE_CONNECTION);
try
{
if (!connection)
connection = std::make_unique<nanodbc::connection>(connection_string, ODBC_CONNECT_TIMEOUT);
}
catch (...)
{
pool->returnObject(std::move(connection));
throw;
}
return std::make_unique<nanodbc::ConnectionHolder>(factory[connection_string], std::move(connection), connection_string);
}
private:
/// [connection_settings_string] -> [connection_pool]
using PoolFactory = std::unordered_map<std::string, nanodbc::PoolPtr>;
PoolFactory factory;
std::mutex mutex;
};
}