MySQL Bugs: #56953: 2013 error at 'waiting for initial communication packet, system error: 61

Bug #56953	2013 error at 'waiting for initial communication packet, system error: 61
Submitted:	22 Sep 2010 21:19	Modified:	13 Oct 2010 20:19
Reporter:	Plou Francois	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server	Severity:	S2 (Serious)
Version:	5.1.43-powerpc-64bit	OS:	IBM AIX (5.3)
Assigned to:		CPU Architecture:	Any
Tags:	2013, communication packet, system error 61

Description:
(2013 Lost connection to MySQL server at 'waiting for initial communication packet', system error: 61)

We get this error in production environment from C program that tries to initiate a connection to the database.
We wrote a test program that continuously (every 7 seconds) tries to connect to the database with the following API :

...
  unsigned int tmax = 5;	// 5 seconds

...

    mysql_options (SGBD, MYSQL_OPT_CONNECT_TIMEOUT, (char*)&tmax);

    time_t start = time (NULL);
    int LOC_good = (mysql_real_connect(SGBD, host, user, pass, base, port, (char*)0, 0U) != (MYSQL*)0);
    time_t done = time (NULL);

    if(done-start > 1)
        printf("Connection lente (%d secondes) a %s\n",done-start,hour());

    if(!LOC_good) {
      printf("erreur connexion (%d %s) a %s", mysql_errno(SGBD), mysql_error(SGBD), hour());
      break;
    }

    mysql_close(SGBD);
    fflush(stdout);

    if(pause) sleep(pause);
...

We connect to the database to localhost address and to a dedicated port different than the standard 3306.
So the connection takes more than 5 seconds to complete. As our code does not yet manage a pooled connection, this slow connection process is a problem in our workflow.

Do you have any clue about that ?

Regards

How to repeat:
We discovered that the 2013 error occurs when a slow query (30 to 60 seconds) is in progress during the mysql_real_connect execution.

How long is the connection needing when you use plane CLI?

Yes, I meant the MySQL Command Line Client.

Yes I dit the test on a qualification environment (same OS, same mySQL, same SGBD).

When a huge select request is in progress (50 seconds to process), the C program detects a connection time of 6 seconds. In the same time, a simple loop with a shell program calling mysql client detects the same average time.

The shell test program is the following :

#!/bin/sh
#############

while true
do
        time mysql -u root <database> <<!
exit
!
        sleep 2
done

One output sample :

réel    0m6,90s
utilisateur     0m0,01s
sys     0m0,00s

Regards

Thank you for the feedback.

This is most likely not a bug, but something wrong in your environment. In C program you connecting using TCP connection, please try connect via socket also. Check with current version of MySQL 5.1.50 too.

Thanks.

In this particular environnement, the mySQL database is hosted on same server as our application. But usually this is not the case, so the C program has to connect via TCP socket.

Anyway, I will do the test with the socket and with the 5.1.50 release.

I will let you know about results.

Regards

We did not install the latest release.

Instead we reduced the number of open connection to the database (via C3P0 pool parameters) then set the thread_cache_size to 200.
The problem is solved.

Francois