Mysql [Warning] Aborted connection

2015-08-01 11:13:31 5736 [Warning] Aborted connection 668 to db: 'dbname' user: 'dbuser' host: '10.0.4.54' (Got an error reading communication packets)

We have java 10 servers connecting to DB, at times we are seeing error like this, please let me know what should be done to solve the types of errors?

We are using Mysql percona
sivaatluriAsked:
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sivaatluriAuthor Commented:
My.cnf configuration


[mysql]

# CLIENT #
port                           = 3306
socket                         = /var/lib/mysql/mysql.sock
[mysqld]

# GENERAL #
user                           = mysql
default-storage-engine         = InnoDB
socket                         = /var/lib/mysql/mysql.sock
pid-file                       = /var/lib/mysql/mysql.pid
skip_name_resolve
# MyISAM #
key-buffer-size                = 32M
myisam-recover                 = FORCE,BACKUP
# SAFETY #
max-allowed-packet             = 16M
max-connect-errors             = 1000000
# DATA STORAGE #
datadir                        = /srv/mysql/

# BINARY LOGGING #
server-id                      = 1
log-bin                        = /srv/mysqllogs/mysql-bin
max_binlog_size                = 512M
expire-logs-days               = 4
sync-binlog                    = 1

# CACHES AND LIMITS #
tmp-table-size                 = 128M
max-heap-table-size            = 128M
query-cache-type               = 1
query-cache-size               = 512M
max-connections                = 4096
thread-cache-size              = 100
open-files-limit               = 65535
table-definition-cache         = 4096
table-open-cache               = 10240

# INNODB #
innodb-flush-method            = O_DIRECT
innodb-log-files-in-group      = 2
innodb-log-file-size           = 256M
innodb-flush-log-at-trx-commit = 1
innodb-file-per-table          = 1
innodb-buffer-pool-size        = 5G

# LOGGING #
log-error                      = /srv/mysqllogs/mysql-error.log
general_log_file        = /srv/mysqllogs/mysql.log
general_log             = 1
log_warnings = 2

log-queries-not-using-indexes  = 1
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gheistCommented:
Since java 10 is prerelease problems should be expected and it must be operated by professionals who know how to fix bugs.

what are ulimits (ulimit -a) passed to MySQL daemon?
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sivaatluriAuthor Commented:
Gheist,

 Its not Java 10, its JDK 6.. Not sure how Mysql Problems are related to java.

How I check the ulimit values set for mysql
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gheistCommented:
warning is not a problem
usually Linux allows 1024 file descriptors per user unless you edit limits.conf
table_open_cache + max_connections or open file limit hardly fits in there
the parameters are so off real world that I can only suggest running mysqltuner.pl and make recommended adjustments.
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Bhavesh ShahLead AnalysistCommented:
hi.

did you checked the below link?

you might get an idea

https://dev.mysql.com/doc/refman/5.0/en/communication-errors.html

can you share the log file.?
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NerdsOfTechTechnology ScientistCommented:
Make sure all your users are calling mysql_close() on exit.

Users could be timing out without requests (sleeping time out).

It might even be chalked up to a really bad and/or slow network connection.

Check your logs for more details

More more common issues related to this error, also see:
https://dev.mysql.com/doc/refman/5.0/en/communication-errors.html
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sivaatluriAuthor Commented:
I have separate mysql-error log

Its logs only lines like this

2015-08-01 11:13:31 5736 [Warning] Aborted connection 668 to db: 'dbname' user: 'dbuser' host: '10.0.4.54' (Got an error reading communication packets)

Network connection issues are not applicable as we are on Ec2 cloud. Networking is perfect

Any thing else you can help me with?
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gheistCommented:
There is no error.
Figure out why client did running on 10.0.4.54 not close mysql connection correctly or mask out this warning message.
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NerdsOfTechTechnology ScientistCommented:
They are likely timing out or not closing the connection, and the server is closing the connection for them.

It might help to have more than one user name to pinpoint the user who is throwing the warning too.
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sivaatluriAuthor Commented:
Does that mean the client running on 10.0.4.54 haven't received response in the required time & closed the connection.

Or

The Mysql is not accepting new connections because it's connections are full & keep putting the client in queue due to which the client has closed the connection.
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gheistCommented:
Most likely client crashed without closing the socket.
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NerdsOfTechTechnology ScientistCommented:
As the author hypothesized, the open connections and time outs may be filling up slots faster than the server can recycle them for additional users to logon.
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gheistCommented:
mysqltuner.pl should tell on the spot what is wrong.
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