Getting error: unable to connect to MySQL server on server "SERVER_IP" (99)

Question

I use PHP5 and MySQL, everything is fine until more than 9,000 petitions are sent to the MySQL server.

For example, I'm trying to make 10,000 inserts from a CSV file with 10,000 records (lines). When the loop is running, I got this error:

Unable to connect to MySQL server on '192.168.10.11' (99).

I wrote a little loop to make 10,000 select field_id from table where field_id = XX , and I got the same error.

My LAMP uses Debian Squeeze, PHP5, MySQL Server 5.1, Apache2

Important note: there are no errors using the MySQL Workbench or the MySQL CLI, this is only in a web environment.

This is my.conf

 # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp language = /usr/share/mysql/english skip-external-locking skip-name-resolve wait_timeout=60 connect_timeout=10 max_allowed_packet=16M interactive_timeout=120 join_buffer_size=1M query_cache_size=128M query_cache_limit=2M table_cache=1024 sort_buffer_size=8M read_buffer_size=2M read_rnd_buffer_size=4M key_buffer = 256M key_buffer_size=64M # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. #bind-address = 127.0.0.1 # # * Fine Tuning # #key_buffer = 16M #max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #max_connections = 100 #table_cache = 64 #thread_concurrency = 10 # # * Query Cache Configuration # #query_cache_limit = 1M #query_cache_size = 16M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 # # Error logging goes to syslog due to /etc/mysql/conf.d/mysqld_safe_syslog.cnf. # # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem innodb_buffer_pool_size=1024M [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ 

Answer 1

You have timeout problems and too many connections. Try omitting wait_timeout and possibly interactive_timeout.

I don’t know if you use PDO (recommended from all the messages that I saw here), but try to make the connection to MySQL permanent so that there is no need to open new connections for each update.

Answer 2

This worked for me on several MariaDB installations:

Step 1 - Change sysctl:

sudo vim /etc/sysctl.conf

Step 2 - Insert the following lines:

net.ipv4.tcp_tw_reuse=1 net.ipv4.tcp_tw_recycle=1 net.ipv4.tcp_fin_timeout=30 net.ipv4.tcp_max_syn_backlog=8192

This will mainly support connections open for a longer period.

Step 3: Apply Settings

sudo sysctl -p

This should fix the problem.

Answer 3

This helped me a lot when using the OTRS storage switching tool (for version 3.1.7) bin/otrs.ArticleStorageSwitch.pl -s ArticleStorageDB -d ArticleStorageFS since it only increased the number of connections and died by 28k;) With your settings, it went up to a maximum of 400 . Hooray!