MySQLConnectionPool.h

// Licensed to the Apache Software Foundation (ASF) under one
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// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
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// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

#include <mysql++/mysql++.h>

#include <unistd.h>
#include <atomic>
#include <string>

#include "utils/Log.h"

namespace zilliz {
namespace milvus {
namespace engine {
namespace meta {

class MySQLConnectionPool : public mysqlpp::ConnectionPool {
 public:
    // The object's only constructor
    MySQLConnectionPool(std::string dbName, std::string userName, std::string passWord, std::string serverIp,
                        int port = 0, int maxPoolSize = 8)
        : db_(dbName),
          user_(userName),
          password_(passWord),
          server_(serverIp),
          port_(port),
          max_pool_size_(maxPoolSize) {
        conns_in_use_ = 0;
        max_idle_time_ = 10;  // 10 seconds
    }

    // The destructor.  We _must_ call ConnectionPool::clear() here,
    // because our superclass can't do it for us.
    ~MySQLConnectionPool() override {
        clear();
    }

    mysqlpp::Connection*
    grab() override;

    // Other half of in-use conn count limit
    void
    release(const mysqlpp::Connection* pc) override;

    //    int getConnectionsInUse();
    //
    //    void set_max_idle_time(int max_idle);

    std::string
    getDB();

 protected:
    // Superclass overrides
    mysqlpp::Connection*
    create() override;

    void
    destroy(mysqlpp::Connection* cp) override;

    unsigned int
    max_idle_time() override;

 private:
    // Number of connections currently in use
    std::atomic<int> conns_in_use_;

    // Our connection parameters
    std::string db_, user_, password_, server_;
    int port_;

    int max_pool_size_;

    unsigned int max_idle_time_;
};

}  // namespace meta
}  // namespace engine
}  // namespace milvus
}  // namespace zilliz