mysql error number: 0 - Lost Connections

[dustyb]

I have been getting the following error message consistently since the launch of our vB 3.01 site last month, around a half dozen of them per day.

Database error in vBulletin :

Link-ID == false, connect failed: Lost connection to MySQL server during query mysql error:

mysql error number: 0

I added the mysql error message to the relevant PHP file, so I'm getting a little more detail after the connect failed: I've seen this error posted a couple times and the response usually involves tweaks to the mysql conf. But I'm not sure I've seen anyone report resolution. I'm using a variant of big.cnf. Here it is. If anybody sees anything I might tweak, I'd be much obliged.

[client]
#password       = your_password
port            = 3306
socket          = /var/lib/mysql/mysql.sock

# Here follows entries for some specific programs

# The MySQL server
[mysqld]
max_connections = 256
wait_timeout    = 28800
port            = 3306
socket          = /var/lib/mysql/mysql.sock
skip-locking
key_buffer      = 256M
max_allowed_packet = 1M
table_cache     = 256
sort_buffer_size = 2M
read_buffer_size = 2M
myisam_sort_buffer_size = 64M
thread_cache    = 8
query_cache_size= 20M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 4

# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (via the "enable-named-pipe" option) will render mysqld useless!
#
#skip-networking

# Replication Master Server (default)
# binary logging is required for replication
#log-bin
# required unique id between 1 and 2^32 - 1
# defaults to 1 if master-host is not set
# but will not function as a master if omitted
#server-id      = 1

# Replication Slave (comment out master section to use this)
#
# To configure this host as a replication slave, you can choose between
# two methods :
#
# 1) Use the CHANGE MASTER TO command (fully described in our manual) -
#    the syntax is:
#
#    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,
#    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;
#
#    where you replace <host>, <user>, <password> by quoted strings and
#    <port> by the master's port number (3306 by default).
#
#    Example:
#
#    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,
#    MASTER_USER='joe', MASTER_PASSWORD='secret';
#
# OR
#
# 2) Set the variables below. However, in case you choose this method, then
#    start replication for the first time (even unsuccessfully, for example
#    if you mistyped the password in master-password and the slave fails to
#    connect), the slave will create a master.info file, and any later
#    change in this file to the variables' values below will be ignored and
#    overridden by the content of the master.info file, unless you shutdown
#    the slave server, delete master.info and restart the slaver server.
#    For that reason, you may want to leave the lines below untouched
#    (commented) and instead use CHANGE MASTER TO (see above)
#
# required unique id between 2 and 2^32 - 1
# (and different from the master)
# defaults to 2 if master-host is set
# but will not function as a slave if omitted
#server-id       = 2
#
# The replication master for this slave - required
#master-host     =   <hostname>
#
# The username the slave will use for authentication when connecting
# to the master - required
#master-user     =   <username>
#
# The password the slave will authenticate with when connecting to
# the master - required
#master-password =   <password>
#
# The port the master is listening on.
# optional - defaults to 3306
#master-port     =  <port>
#
# binary logging - not required for slaves, but recommended
#log-bin

# Point the following paths to different dedicated disks
#tmpdir         = /tmp/
#log-update     = /path-to-dedicated-directory/hostname

# Uncomment the following if you are using BDB tables
#bdb_cache_size = 64M
#bdb_max_lock = 100000
# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /var/lib/mysql/
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = /var/lib/mysql/
#innodb_log_arch_dir = /var/lib/mysql/
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 256M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 64M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

[mysqldump]
quick
max_allowed_packet = 16M

[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates

[isamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[myisamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

I'm running RedHat ES 3 on a Dell PowerEdge 2650 with 1GB RAM and a single 1.2 Ghz Xeon hyper-thread processor. Here is a top sorted by memory with the mysqld processes on top:

12:15:11  up 42 days, 21:47,  1 user,  load average: 0.00, 0.02, 0.00
73 processes: 72 sleeping, 1 running, 0 zombie, 0 stopped
CPU states:  cpu    user    nice  system    irq  softirq  iowait    idle
           total    2.3%    0.0%    0.1%   0.0%     0.0%    0.1%   97.2%
           cpu00    0.1%    0.0%    0.0%   0.0%     0.0%    0.1%   99.6%
           cpu01    4.5%    0.0%    0.3%   0.0%     0.0%    0.1%   94.8%
Mem:  1028540k av,  860616k used,  167924k free,       0k shrd,  182896k buff
                    595396k actv,   40424k in_d,   13760k in_c
Swap: 1020088k av,    1992k used, 1018096k free                  400448k cached

 3398 mysql     15   0  115M 115M  1748 S     0.0 11.4   0:23   0 mysqld
 3399 mysql     15   0  115M 115M  1748 S     0.0 11.4   0:16   1 mysqld
 3400 mysql     20   0  115M 115M  1748 S     0.0 11.4   0:00   1 mysqld
 3401 mysql     15   0  115M 115M  1748 S     0.0 11.4   0:00   1 mysqld
 3402 mysql     25   0  115M 115M  1748 S     0.0 11.4   0:00   1 mysqld
 3403 mysql     15   0  115M 115M  1748 S     0.0 11.4   0:00   1 mysqld
 3404 mysql     24   0  115M 115M  1748 S     0.0 11.4   0:00   1 mysqld
 3405 mysql     15   0  115M 115M  1748 S     0.0 11.4  19:58   1 mysqld
 3406 mysql     15   0  115M 115M  1748 S     0.0 11.4   0:00   1 mysqld
 3407 mysql     15   0  115M 115M  1748 S     0.0 11.4   1:08   0 mysqld
 3408 mysql     15   0  115M 115M  1748 S     0.0 11.4   6:29   0 mysqld
 3410 mysql     15   0  115M 115M  1748 S     0.0 11.4   6:29   1 mysqld
 3428 mysql     15   0  115M 115M  1748 S     0.0 11.4   6:48   1 mysqld
 3562 mysql     15   0  115M 115M  1748 S     0.0 11.4   6:48   1 mysqld
 4932 mysql     15   0  115M 115M  1748 S     0.0 11.4   6:04   0 mysqld
14536 mysql     15   0  115M 115M  1748 S     0.0 11.4   5:15   0 mysqld
14542 mysql     15   0  115M 115M  1748 S     0.0 11.4   5:02   0 mysqld
14545 mysql     15   0  115M 115M  1748 S     0.0 11.4   5:12   0 mysqld

Always appreciate the good folks on this board, thanks in advance.

[NTLDR]

If you haven't done so already I'd suggest posting this in the Server Configuration forum at vB.com and get eva2000 to take a look at it and see if he notices anything that can be tweaked.