power failure and mysql crash - mysql

I've been using MySql with InnoDb engine for a while and am pretty satisfied with the performance. I got 10 tables and update them twice every second. Recently I had a power outage and was not able to restart the database without setting the innodb_force_recovery to at least 4. But when trying to fix the broken table the database would crash again. I tried optimizing, checking, analyzing and so on, but all resulted in crash.
The error log contains messages like:
InnoDB: Error: page 570 log sequence number 7289495
InnoDB: is in the future! Current system log sequence number 5574939.
Eventually I managed to dump the database via mysqldump (with the innodb_force_recovery at 6) after deleting all files related to a specific table. Then I reinstalled xampp and reloaded the dump. This got me up and running again with only one table lost.
My question is this, how can one corrupt table cause the whole database to crash?
Is there a way to minimize the risk of this happening again, some kind of configuration to increase the robustness against power failures?
I know the obvious answer is to keep a replicate backup database on a separate server, but being in just the testing phase of the development it seems like overkill.
Here's the configuration file I am using.
# Example MySQL config file for small systems.
#
# This is for a system with little memory (<= 64M) where MySQL is only used
# from time to time and it's important that the mysqld daemon
# doesn't use much resources.
#
# You can copy this file to
# C:/xampp2/mysql/bin/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options (in this
# installation this directory is C:/xampp2/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
[client]
# password = your_password
port = 3306
socket = "C:/xampp2/mysql/mysql.sock"
# Here follows entries for some specific programs
# The MySQL server
[mysqld]
port= 3306
socket = "C:/xampp2/mysql/mysql.sock"
basedir = "C:/xampp2/mysql"
tmpdir = "C:/xampp2/tmp"
datadir = "C:/xampp2/mysql/data"
pid_file = "mysql.pid"
# enable-named-pipe
key_buffer = 16M
max_allowed_packet = 1G
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
log_error = "mysql_error.log"
# Change here for bind listening
# bind-address="127.0.0.1"
# bind-address = ::1 # for ipv6
# Where do all the plugins live
plugin_dir = "C:/xampp2/mysql/lib/plugin/"
# 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!
#
# commented in by lampp security
#skip-networking
#skip-federated
# Replication Master Server (default)
# binary logging is required for replication
# log-bin deactivated by default since XAMPP 1.4.11
#log-bin=mysql-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=mysql-bin
# Point the following paths to different dedicated disks
#tmpdir = "C:/xampp2/tmp"
#log-update = /path-to-dedicated-directory/hostname
# Uncomment the following if you are using BDB tables
#bdb_cache_size = 4M
#bdb_max_lock = 10000
# Comment the following if you are using InnoDB tables
#skip-innodb
innodb_data_home_dir = "C:/xampp2/mysql/data"
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = "C:/xampp2/mysql/data"
#innodb_log_arch_dir = "C:/xampp2/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 = 2G
innodb_additional_mem_pool_size = 16M
## Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 50M
innodb_log_buffer_size = 20M
innodb_flush_log_at_trx_commit = 2
innodb_lock_wait_timeout = 50
innodb_buffer_pool_instances = 4
## UTF 8 Settings
#init-connect=\'SET NAMES utf8\'
#collation_server=utf8_unicode_ci
#character_set_server=utf8
#skip-character-set-client-handshake
#character_sets-dir="C:/xampp2/mysql/share/charsets"
[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 = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout

InnoDB is very conservative when it comes to data consistency. If it catches anything unexpected (wrong checksum, header value, anything) it intentionally crashes in order not to damage data.
How "to minimize the risk of this happening again"?
The best is to keep safe defaults of innodb_flush_log_at_trx_commit, doublewrite, etc. Internet is full of thoughtless advices on "how to make MySQL faster", but it comes with price, you know.

Related

MySQL “#2006 - MySQL server has gone away” in phpMyAdmin

I am trying to upload a 10 MB CSV Excel file with over 100k entries, and I keep getting the "MySQL server has gone away" error in phpMyAdmin. I am using WAMP Server and I changed all the variables I could find the in my.ini file, but with no results. Neither after restarting the server.
I've changed:
max_allowed_packet = 1000M
innodb_log_file_size = 500M
innodb_log_buffer_size = 800M
innodb_lock_wait_timeout = 600
The whole my.ini file looks like this:
enter co# Example MySQL config file for medium systems.
#
# This is for a system with little memory (32M - 64M) where MySQL plays
# an important part, or systems up to 128M where MySQL is used together with
# other programs (such as a web server)
#
# 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
[client]
#password = your_password
port = 3306
socket = /tmp/mysql.sock
# Here follows entries for some specific programs
# The MySQL server
[wampmysqld]
port = 3306
socket = /tmp/mysql.sock
key_buffer_size = 16M
max_allowed_packet = 1000M
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 8M
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
basedir=c:/wamp/bin/mysql/mysql5.6.17
log-error=c:/wamp/logs/mysql.log
datadir=c:/wamp/bin/mysql/mysql5.6.17/data
lc-messages-dir=c:/wamp/bin/mysql/mysql5.6.17/share
# Change your locale here !
lc-messages=fr_FR
# Avoid warning
explicit_defaults_for_timestamp = TRUE
# 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
# Disable Federated by default
skip-federated
# Replication Master Server (default)
# binary logging is required for replication
log-bin=mysql-bin
# binary logging format - mixed recommended
binlog_format=mixed
# 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)
# New for MySQL 5.6 if no slave
skip-slave-start
#
# 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=mysql-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 InnoDB tables
#innodb_data_home_dir = C:\mysql\data/
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = C:\mysql\data/
#innodb_log_arch_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 = 511M
#innodb_additional_mem_pool_size = 2M
# Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 500M
innodb_log_buffer_size = 800M
#innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 600
[mysqldump]
quick
max_allowed_packet = 1000M
[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
[isamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout
[mysqld]
port=3306
explicit_defaults_for_timestamp = TRUE
Try increasing the setting for wait_timeout
If that doesn't work, try increasing for interactive_timeout.
Also, increasing the lock times on innodb is at the query level; this means how long a query will wait to acquire a lock if another query has the lock. This will then cause an to be thrown back to the client similar to the effect of 1205 Lock wait timeout exceeded.

xampp mysql server not starting

Help please I can't start the sql database server in xampp. This was after upgrading to os x Yosemite. This is the error message I get for phpmyadmin:
Welcome to phpMyAdmin
Error
MySQL said: Documentation
2002 - No such file or directory
The server is not responding (or the local server's socket is not correctly configured).
Connection for controluser as defined in your configuration failed.
Thank you so much!
Here is the command I tried in terminal (which I got from another person on stack overflow who seemed to have a similar problem):
sudo /Applications/XAMPP/xamppfiles/bin/mysql.server start
Here was the error message:
Starting MySQL
. ERROR! The server quit without updating PID file (/Applications/XAMPP/xamppfiles/var/mysql/imac.local.pid).
sql conf file:
# Example MySQL config file for medium systems.
#
# This is for a system with little memory (32M - 64M) where MySQL plays
# an important part, or systems up to 128M where MySQL is used together with
# other programs (such as a web server)
#
# 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 /Applications/XAMPP/xamppfiles/var/mysql) 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
[client]
#password = your_password
port = 3306
socket = /Applications/XAMPP/xamppfiles/var/mysql/mysql.sock
# Here follows entries for some specific programs
# The MySQL server
[mysqld]
user = mysql
port=3306
socket = /Applications/XAMPP/xamppfiles/var/mysql/mysql.sock
skip-external-locking
key_buffer = 16M
max_allowed_packet = 1M
table_open_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
# Where do all the plugins live
plugin_dir = /Applications/XAMPP/xamppfiles/lib/mysql/plugin/
# 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!
#
# commented in by xampp security
#skip-networking
skip-networking
# Replication Master Server (default)
# binary logging is required for replication
# log-bin deactivated by default since XAMPP 1.4.11
#log-bin=mysql-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=mysql-bin
# Point the following paths to different dedicated disks
tmpdir = /Applications/XAMPP/xamppfiles/temp/mysql
#log-update = /path-to-dedicated-directory/hostname
# Uncomment the following if you are using BDB tables
#bdb_cache_size = 4M
#bdb_max_lock = 10000
# Comment the following if you are using InnoDB tables
#skip-innodb
innodb_data_home_dir = /Applications/XAMPP/xamppfiles/var/mysql/
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /Applications/XAMPP/xamppfiles/var/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 = 16M
# Deprecated in 5.6
#innodb_additional_mem_pool_size = 2M
# Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 5M
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 = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout
!include /Applications/XAMPP/xamppfiles/mysql/my.cnf
For all of you to know I ended up doing a fresh reinstall of xampp. It now works fine! Here was what I did:
backup files and database (if possible)
quit 'manager os x'
run the uninstaller
delete the xampp folder
download xampp from the site
Run the installer for xampp
run security program in terminal
move your stuff back to the xampp folder
All in all I found that xampp (1.8.3-5) is compatible with OS X Yosemite.

#2006 - MySQL server has gone away when restoring mysql dump [duplicate]

This question already has answers here:
ERROR 2006 (HY000): MySQL server has gone away
(24 answers)
Closed 5 years ago.
Environment : Windows 7
XAMPP 1.7.3
I have gone through Many stackoverflow solution for this problem and changed setting in file
my.ini
which now looks like
# Example MySQL config file for medium systems.
#
# This is for a system with little memory (32M - 64M) where MySQL plays
# an important part, or systems up to 128M where MySQL is used together with
# other programs (such as a web server)
#
# 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 #localstatedir#) 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
[client]
#user = your_username
#password = your_password
host = .
port = 3306
socket = "MySQL"
# Here follows entries for some specific programs
# The MySQL server
[mysqld]
basedir = "D:/Program Files/xampp/mysql/"
datadir = "D:/Program Files/xampp/mysql/data/"
port = 3306
socket = "MySQL"
skip-locking
key_buffer = 16M
max_allowed_packet = 254M
table_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
default-time-zone = "Asia/Calcutta"
log_error = "D:/Program Files/xampp/mysql/data/mysql.err"
pid_file = "mysql.pid"
general_log = 0
general_log_file = "D:/Program Files/xampp/mysql/data/mysql.log"
slow_query_log = 0
slow_query_log_file = "D:/Program Files/xampp/mysql/data/mysql-slow.log"
# 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
enable-named-pipe
# Disable Federated by default
skip-federated
# Replication Master Server (default)
# binary logging is required for replication
#log-bin = mysql-bin
# binary logging format - mixed recommended
#binlog_format = mixed
# 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 = mysql-bin
# Point the following paths to different dedicated disks
tmpdir = "D:/Program Files/xampp/tmp/"
#log-update = "D:/Program Files/xampp/tmp/mysql"
# Uncomment the following if you are using InnoDB tables
#skip-innodb
innodb_data_home_dir = "D:/Program Files/xampp/mysql/data/"
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = "D:/Program Files/xampp/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 = 16M
innodb_additional_mem_pool_size = 2M
# Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 5M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50
[mysqldump]
quick
max_allowed_packet = 254M
[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
[isamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout
but still i am getting same error. I am trying to restore mysqldump of size 160MB which has many BLOB contents .
Try changing the max_allowed_packet setting to a larger value in the server.
Open "my.ini/cnf", located in your MySQL installation folder, and under [mysqld] section change "max_allowed_packet = 64M" and don't forget to restart the server. You can check the value by executing:
SHOW VARIABLES LIKE 'max_allowed_packet';
Refer: http://dev.mysql.com/doc/refman/5.0/en/gone-away.html
Here is an explanation of how to solve that http://eppand.com/solution-to-mysql-error-2006-in-xampp/
If someone needs, there is untouched config files for XAMPP:
https://drive.google.com/folderview?id=0B8SVZZwmcOIYNjdwbkluUTJERTA&usp=sharing

Cannot connect to local mysql server in netbeans

I'm experimenting with netbeans and Java for a weekend project, and I'm having a hard time trying to get netbeans to connect to my local mysql server.
Here's the contents of my.cnf:
# MySQL config file for medium systems.
#
# This is for a system with little memory (32M - 64M) where MySQL plays
# an important part, or systems up to 128M where MySQL is used together with
# other programs (such as a web server)
#
# MySQL programs look for option files in a set of
# locations which depend on the deployment platform.
# You can copy this option file to one of those
# locations. For information about these locations, see:
# http://dev.mysql.com/doc/mysql/en/option-files.html
#
# 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
[client]
#password = your_password
port = 3306
socket = /var/run/mysqld/mysqld.sock
# Here follows entries for some specific programs
# The MySQL server
[mysqld]
port = 3306
socket = /var/run/mysqld/mysqld.sock
datadir = /var/lib/mysql
skip-external-locking
key_buffer_size = 16M
max_allowed_packet = 1M
table_open_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
# 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
log-bin=mysql-bin
# binary logging format - mixed recommended
binlog_format=mixed
# 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=mysql-bin
# 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
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 16M
#innodb_additional_mem_pool_size = 2M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 5M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50
tmpdir = "/tmp/"
[mysqldump]
quick
max_allowed_packet = 16M
[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
[myisamchk]
key_buffer_size = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout
The answer to this question recomments using a version of MySQL connector for java downloaded from the mysql website which I did with no luck, I've tried stopping the server anddeleting /var/lib/mysql and re-installing it with no luck either. A post on the NetBeans forums with no results.
I can connect to the server using MySQL Workbench, so I know my settings work which makes me think the issue is with NetBeans, but I'm not sure, can someone please point me in the right directon? Thank you for your time and consideration.
I don't know why, but for some reason adding the commands to start and stop the mysql daemon seemed fix the issue.
I got the same issue but after spending hours on the internet, I finally figured it out. If I ran both the XAMP containing MYSQL and Netbeans IDE, Everything runs fine. Though it's weird that my username has the admin rights. But everything's working great now so all is good. Hope it might help people in future.

MySQL queries extremely slow in fresh XAMPP installation [closed]

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I just reinstalled Windows 7 and I am trying to get my development environment up and running again. XAMPP installed ok, and my application is in htdocs and all databases have imported fine. I can view them in phpMyAdmin and everything looks intact.
When trying to run the application, queries are so slow that most pages timeout before all the queries can complete.
For example, pages this computer could generate in 3 seconds before, now go up to 30 seconds and the page times out.
This is an XAMPP installation 1.7.7, but I have tried rolling back to their older versions and got the same result.
There is nothing in the log files, as it's not actually erroring out, it's just performing the queries very slowly.
Even navigating the databases via phpMyAdmin takes about 3-10 seconds to load pages whereas it has previously been instant. So this eliminates my application (which also hasn't changed since when it was working very quickly before).
Any ideas what could be causing this big slowdown in a fresh xampp install? Was there something in httpd.conf, php.ini or my.ini I might have setup prevously that got wiped by the fresh install and might now cause the database access to be slow?
Thanks!
The problem appeared to be in the query cache and InnoDB setup for MySQL. Although XAMPP has lines for InnoDB in the my.ini, there were additional that needed to be added.
Below is the config I have saved from my previous build. When I added these to my.ini and restarted the server everything seemed to work at full speed again.
I am not sure whether this fixed an underlying slowdown issue, or if the use of a query cache is now just masking it, but it's working well enough! On with development!
#----------------------------------------------------
# !!!! Query Cache Config !!!!
#----------------------------------------------------
query-cache-size = 524288000
query-cache-limit = 5242880
query-cache-type = 1
#----------------------------------------------------
# !!!! InnoDB Buffer Config !!!!
#----------------------------------------------------
innodb-buffer-pool-size = 1000M
innodb-additional-mem-pool-size = 200M
innodb-log-files-in-group = 2
innodb-log-buffer-size = 10M
innodb-file-per-table = 1
UPDATE
Sample config file that worked using this technique (MySQL 5.7 tested on Windows)
# The following options will be passed to all MySQL clients
[client]
# password = your_password
port = 3306
socket = "C:/xampp/mysql/mysql.sock"
# Here follows entries for some specific programs
# The MySQL server
[mysqld]
port= 3306
socket = "C:/xampp/mysql/mysql.sock"
basedir = "C:/xampp/mysql"
tmpdir = "C:/xampp/tmp"
datadir = "C:/xampp/mysql/data"
pid_file = "mysql.pid"
# enable-named-pipe
key_buffer = 16M
max_allowed_packet = 1M
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
log_error = "mysql_error.log"
# Change here for bind listening
# bind-address="127.0.0.1"
# bind-address = ::1 # for ipv6
# Where do all the plugins live
plugin_dir = "C:/xampp/mysql/lib/plugin/"
# 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!
#
# commented in by lampp security
#skip-networking
#skip-federated
# Replication Master Server (default)
# binary logging is required for replication
# log-bin deactivated by default since XAMPP 1.4.11
#log-bin=mysql-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=mysql-bin
# Point the following paths to different dedicated disks
#tmpdir = "C:/xampp/tmp"
#log-update = /path-to-dedicated-directory/hostname
# Uncomment the following if you are using BDB tables
#bdb_cache_size = 4M
#bdb_max_lock = 10000
# Comment the following if you are using InnoDB tables
#skip-innodb
innodb_data_home_dir = "C:/xampp/mysql/data"
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = "C:/xampp/mysql/data"
#innodb_log_arch_dir = "C:/xampp/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 = 1000M
innodb_additional_mem_pool_size = 200M
## Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 250M
innodb_log_buffer_size = 10M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50
## UTF 8 Settings
#init-connect=\'SET NAMES utf8\'
#collation_server=utf8_unicode_ci
#character_set_server=utf8
#skip-character-set-client-handshake
#character_sets-dir="C:/xampp/mysql/share/charsets"
[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 = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[myisamchk]
key_buffer = 20M
sort_buffer_size = 20M
read_buffer = 2M
write_buffer = 2M
[mysqlhotcopy]
interactive-timeout