max_packet_allowed setting automatically resets 1024(1m). have set higher value @ global level. strange during deployment of war(not always) value reset 1m. value gets reset randomly. if there mysql server restart shouldn't happen copy value global level.
here my.cnf config file content(ubuntu):
# # mysql database server configuration file. # # can copy 1 of: # - "/etc/mysql/my.cnf" set global options, # - "~/.my.cnf" set user-specific options. # # 1 can use long options program supports. # run program --help list of available options , # --print-defaults see understand , use. # # explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # passed mysql clients # has been reported passwords should enclosed ticks/quotes # escpecially if contain "#" chars... # remember edit /etc/mysql/debian.cnf when changing socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # here entries specific programs # following values assume have @ least 32m ram # formally known [safe_mysqld]. both versions parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * basic settings # wait_timeout=115200 max_allowed_packet=500m 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 lc-messages-dir = /usr/share/mysql skip-external-locking # # instead of skip-networking default listen on # localhost more compatible , not less secure. #bind-address = 127.0.0.1 #skip-networking # # * fine tuning # key_buffer = 16m max_allowed_packet = 50m thread_stack = 192k thread_cache_size = 8 # replaces startup script , checks myisam tables if needed # first time touched myisam-recover = backup max_connections = 250 #table_cache = 64 #thread_concurrency = 10 # # * query cache configuration # query_cache_limit = 16m query_cache_size = 16m # # * logging , replication # # both location gets rotated cronjob. # aware log type performance killer. # of 5.1 can enable log @ runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 # # error log - should few entries. # log_error = /var/log/mysql/error.log # # here can see queries long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # following can used easy replay backup logs or replication. # note: if setting replication slave, see readme.debian # other settings may need 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 enabled default 10mb datafile in /var/lib/mysql/. # read manual more innodb related options. there many! # # * security features # # read manual, too, if want chroot! # chroot = /var/lib/mysql/ # # generating ssl certificates recommend openssl gui "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 100m [mysql] #no-auto-rehash # faster start of mysql no tab completition max_allowed_packet = 160m [isamchk] key_buffer = 16m # # * important: additional settings can override file! # files must end '.cnf', otherwise they'll ignored. # !includedir /etc/mysql/conf.d/
there must piece of code changing default value of max_allowed_packet.
you can try log queries identify user or process changing value.
as workaround can try set 'super' privilege admin user prevent others changing max_allowed_packet.
