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Does anyone have any idea of what can cause this weird behaviour and how I go about fixing it?

Erratic Task Manager

This is all coming from MySQL only (both RAM and CPU usage), for about 10 minutes after I reboot my Java game server (that has a pool of 256 connections). There are not that many queries and I think it may be more of a MySQL misconfiguration problem.

My server: 3.20 GHz * 6 core / 24 GB RAM / 64 bit Windows Server 2003.

My game server: Java server, with 256 MySQL connections pool (MyISAM engine), about 500,000 accounts, and 9 million rows of game items in database and about 3,000 players are connected.

After about 15 minutes of the game server reboot, the server resumes its stability and CPU usage drop down to 1% ~ 5% and memory to 6 GB.

Here is a copy of my MySQL configuration. Also, any advice about my MySQL configuration will be appreciated. I really set it up almost at random.

# Example MySQL config file for very large systems.
# This is for a large system with memory of 1G-2G where the system runs mainly
# MySQL.
# You can copy this file to
# /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options (in this
# installation this directory is C:\mysql\data) or
# ~/.my.cnf to set user-specific options.
# In this file, you can use all long options that a program supports.
# If you want to know which options a program supports, run the program
# with the "--help" option.

# The following options will be passed to all MySQL clients
#password   = your_password
port        = 3306
socket      = /tmp/mysql.sock

# Here follows entries for some specific programs

# The MySQL server


port        = 3306
socket      = /tmp/mysql.sock
key_buffer_size = 2572M
max_allowed_packet = 64M
table_open_cache = 512
sort_buffer_size = 128M
read_buffer_size = 128M
read_rnd_buffer_size = 128M
myisam_sort_buffer_size = 500M
thread_cache_size = 32
query_cache_size = 1948M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 12
max_connections = 5000

# 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!

# Replication Master Server (default)
# binary logging is required for replication

# 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:
#    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:
#    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 file, and any later
#    change in this file to the variables' values below will be ignored and
#    overridden by the content of the file, unless you shutdown
#    the slave server, delete 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
# binary logging format - mixed recommended 

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

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = C:\mysql\data/
#innodb_data_file_path = ibdata1:2000M;ibdata2:10M:autoextend
#innodb_log_group_home_dir = C:\mysql\data/
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 384M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 100M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

max_allowed_packet = 64M

# Remove the next comment character if you are not familiar with SQL

key_buffer_size = 256M
sort_buffer_size = 256M
read_buffer = 8M
write_buffer = 8M

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migrated from Aug 14 '11 at 11:42

This question came from our site for professional and enthusiast programmers.

Do you have any log entries from MySQL from this phase? – Sven Aug 14 '11 at 11:57
Does it do this if you only start MySQL without starting your Java stuff? i.e. are you sure your Java stuff is not hammering the DB for the first 15 minutes after it comes up with some kind of processing? – EightBitTony Aug 14 '11 at 13:21
up vote 2 down vote accepted

A few things you can try to narrow down the issue:

  • Check all system logs for relevant messages. I'm not familiar with Windows servers but at least the event log and MySQL's log file. You can also try outputting warnings to the log with --log-warnings.
  • Check the MySQL process list with SHOW PROCESSLIST during the startup to get a better idea of what it is doing.
  • Make sure you shutdown MySQL properly to prevent it from checking/repairing tables on startup.
  • Do a controlled startup where you manually start services one-by-one. Try starting services in different order to see if that matters. Disable all incoming queries. See if anything you do here affects the startup performance and is repeatable.
  • If you have another test/development server available see if you replicate the issue using a copy of the databases. If you can replicate it try using backups to see if begins to occur at a certain point in time or not.
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