Connection issues

[jphz]

I initialized the default minimum of 1000 connections, but after a while, the connections were released. When my SQL request arrived, I reconnected. However, on the Windows platform, I encountered a large number of 10053 errors, which caused the SQL request to be unable to be executed. What should I do?

[jphz]

void DBQuery::start(std::shared_ptr<boost::mysql::connection_pool> pool) {
    pool->async_get_connection(
        std::chrono::seconds(0),
        [this, self = shared_from_this()](boost::system::error_code ec, boost::mysql::pooled_connection connection) {
            if (ec) {
                onFail(ec, "connect");
                return;
            }

            _conn = std::move(connection);
            _conn->async_execute(_sql, _results, _errorInfo,
                                 [this, self = shared_from_this()](boost::system::error_code ec) {
                                     if (ec) {
                                         onFail(ec, "query");
                                         return;
                                     }

                                     LOG_DEBUG(gLogger, "DBService::query type:{} sn:{} sql:{}", _type, _sn, _sql);
                                     _callback(true, self);
                                 });
        });
}

void DBQuery::onFail(boost::system::error_code ec, std::string_view prefix) {
    LOG_ERROR(gLogger, "DBService::{} type:{} sn:{} sql:{} code:{} error:{}", prefix, _type, _sn, _sql, ec.value(),
              ec.message());
    _callback(false, shared_from_this());
}

24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850706 sql:SELECT accountID FROM account WHERE passport='寮犱笁84@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 6916 error DBService::query type:2 sn:1125899906850708 sql:SELECT accountID FROM account WHERE passport='寮犱笁86@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850713 sql:SELECT accountID FROM account WHERE passport='寮犱笁87@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 32532 error DBService::query type:2 sn:1125899906850710 sql:SELECT accountID FROM account WHERE passport='寮犱笁88@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 2612 error DBService::query type:2 sn:1125899906850699 sql:SELECT accountID FROM account WHERE passport='寮犱笁70@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850709 sql:SELECT accountID FROM account WHERE passport='寮犱笁89@abc123'; code:5 error:Mismatched sequence numbers 24-06-24 20:50:25 6916 error DBService::query type:2 sn:1125899906850711 sql:SELECT accountID FROM account WHERE passport='寮犱笁90@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 2612 error DBService::query type:2 sn:1125899906850716 sql:SELECT accountID FROM account WHERE passport='寮犱笁91@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 12928 error DBService::query type:2 sn:1125899906850714 sql:SELECT accountID FROM account WHERE passport='寮犱笁92@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 12668 error DBService::query type:2 sn:1125899906850719 sql:SELECT accountID FROM account WHERE passport='寮犱笁93@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850718 sql:SELECT accountID FROM account WHERE passport='寮犱笁94@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 32532 error DBService::query type:2 sn:1125899906850717 sql:SELECT accountID FROM account WHERE passport='寮犱笁95@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 12928 error DBService::query type:2 sn:1125899906850727 sql:SELECT accountID FROM account WHERE passport='寮犱笁97@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850720 sql:SELECT accountID FROM account WHERE passport='寮犱笁96@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850721 sql:SELECT accountID FROM account WHERE passport='寮犱笁99@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850722 sql:SELECT accountID FROM account WHERE passport='寮犱笁98@abc123'; code:5 error:Mismatched sequence numbers 24-06-24 20:50:25 32532 error DBService::query type:2 sn:1125899906850723 sql:SELECT accountID FROM account WHERE passport='寮犱笁101@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 6916 error DBService::query type:2 sn:1125899906850724 sql:SELECT accountID FROM account WHERE passport='寮犱笁100@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 6916 error DBService::query type:2 sn:1125899906850726 sql:SELECT accountID FROM account WHERE passport='寮犱笁102@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 6916 error DBService::query type:2 sn:1125899906850729 sql:SELECT accountID FROM account WHERE passport='寮犱笁105@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 12928 error DBService::query type:2 sn:1125899906850728 sql:SELECT accountID FROM account WHERE passport='寮犱笁104@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850733 sql:SELECT accountID FROM account WHERE passport='寮犱笁106@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。 24-06-24 20:50:25 29400 error DBService::query type:2 sn:1125899906850730 sql:SELECT accountID FROM account WHERE passport='寮犱笁108@abc123'; code:5 error:Mismatched sequence numbers 24-06-24 20:50:25 5708 error DBService::query type:2 sn:1125899906850731 sql:SELECT accountID FROM account WHERE passport='寮犱笁107@abc123'; code:10053 error:你的主机中的软件中止了一个已建立的连接。

[anarthal]

What's your server's max_connections? A possible cause is increasing the number of connections in pool_params but not increasing it in the server. What's the result of running SELECT @@max_connections in your MySQL server?

[jphz]

[jphz]

I use SHOW STATUS LIKE 'Threads connected'; At the beginning, it was 1000, but after a while, it will become 1

[anarthal]

After how much time did the connections die? Reading the documentation for that error code it might be related to anti-malware software killing connections. Is your server running under your same Windows machine too?

[jphz]

They are all on the same machine and disappear in about a minute

[jphz]

I think I found the problem. The wait_time setting is too short and only lasts for 100 seconds.

[jphz]

If it is for this reason, why do disconnected connections still exist in the connection pool? Or why did I receive a disconnected connection?

[anarthal]

Do you mean wait_timeout? Having it set to 100 is a problem, yes.

Connections in the pool don't have a way of detecting that the connection was closed by the server, at least not immediately. Unused connections actively check for liveliness by using async_ping, every pool_params::ping_interval (by default, 1h). Pings prevent connections from closing, and trigger reconnections if they fail. That 1h is less than the default wait_timeout.

In your case, the server closes the connection but the pool doesn't have a way to detect it. When you get a connection, your operation fails and the connection gets returned to the pool. The pool tries to reset the connection and fails (it's closed), and then reconnects it.

If you need to set wait_timeout to a value smaller than 1h, you will need to adjust ping_interval. It should always be less than wait_timeout.

[jphz]

If it defaults to 8 hours, there won't be any problem, right.

[jphz]

/**
 * \brief The health-check interval.
 * \details
 * If a connection becomes idle and hasn't been handed to the user for
 * `ping_interval`, a health-check will be performed (using \ref any_connection::async_ping).
 * Pings will be sent with a periodicity of `ping_interval` until the connection
 * is handed to the user, or a ping fails.
 * \n
 * Set this interval to zero to disable pings.
 * \n
 * This value must not be negative.
 */

I saw the code comments, and the unused connection will ping once every hour. Due to my previous setting of only 100sec, the connection was closed and not detected. Then, I used this connection again, resulting in network reconnection issues.

[anarthal]

Great. I've opened an issue to state this more clearly in the docs. I'll be closing this one.

[jphz]

Thank you very much.