Detailed explanation of mysql5.6 master-slave setup and asynchronous issues

Detailed explanation of mysql5.6 master-slave setup and asynchronous issues

System: centos6.6

Master: 192.168.142.129 mysql-5.6.30.tar.gz

From: 192.168.142.130 192.168.142.131 mysql-5.6.30.tar.gz

1. MySQL master-slave replication principle

mysql5.6 master-slave setup and master-slave asynchrony problem

(1) The master records the changes in the binary log;

(2) The slave copies the master's binary log events to its relay log; the slave's I/O thread reads events from the master's binary log and writes them to the relay log;

(3) The slave redoes the events in the relay log, changing the data to reflect its own. The slave's SQL thread reads events from the relay log and replays them locally to make them consistent with the data in the master.

Steps to implement mysql master-slave:

1. Use the mysqldump command to back up the database.

2. Check the location of the master node binary

3. Create a backup user and authorize (replication client.replication slave)

4. Modify the server-id from the server. It must be different from the server-id of the main MySQL. Enable the relay date and disable the binary date.

5. Import data from the database and use the authorized user to connect to the main MySQL

6. Start slave

The SQL language is divided into the following categories: query language DQL, control language DCL, manipulation language DML, and definition language DDL. Transaction Control TCL.

DQL (Data QUERY Languages) statement: a database definition statement used to query a query block consisting of a SELECT clause, a FROM clause, and a WHERE clause, such as: select–from–where–grouop by–having–order by–limit

DDL (Data Definition Languages) statement: that is, database definition statement, used to create tables, indexes, views, stored procedures, triggers, etc. in the database. Commonly used statement keywords are CREATE, ALTER, DROP, TRUNCATE, COMMENT, RENAME. The structure of the add, delete and modify table

DML (Data Manipulation Language) statements: data manipulation statements used to query, add, update, delete, etc. Commonly used statement keywords are: SELECT, INSERT, UPDATE, DELETE, MERGE, CALL, EXPLAIN PLAN, LOCK TABLE, including general additions, deletions, modifications and queries. Add, delete and modify table data

DCL (Data Control Language) statement: data control statement, used to grant/revoke permissions on the database and its fields (DCL is short name of Data Control Language which includes commands such as GRANT and mostly concerned with rights, permissions and other controls of the database system.). Commonly used statement keywords are: GRANT, REVOKE.

TCL (Transaction Control Language) statements: transaction control statements, used to control transactions. Commonly used statement keywords are: COMMIT, ROLLBACK, SAVEPOINT, SET TRANSACTION.

2. MySQL compilation and installation

#!/bin/bash
yum -y install make gcc gcc-c++ openssl openssl-devel pcre-devel gd cmake ncurses ncurses-devel
id -u mysql
if [ `echo $?` -ne 0 ];
then
groupadd mysql
useradd -M -g mysql -s /sbin/nologin mysql
fi

if [ ! -d "/usr/local/mysql" ];
then
    mkdir -p /usr/local/mysql
fi
mkdir -p /data/mysql
chown -R mysql:mysql /data/mysql
cd /home/soft/ #Software storage directory tar zxvf mysql-5.6.30.tar.gz
cd mysql-5.6.30

cmake -DCMAKE_INSTALL_PREFIX=/usr/local/mysql -DSYSCONFDIR=/etc -DMYSQL_DATADIR=/data/mysql/data -DINSTALL_MANDIR=/usr/share/man -DMYSQL_TCP_PORT=3306 -DMYSQL_UNIX_ADDR=/tmp/mysql.sock -DDEFAULT_CHARSET=utf8 -DEXTRA_CHARSETS=all -DDEFAULT_COLLATION=utf8_general_ci -DWITH_READLINE=1 -DWITH_SSL=system -DWITH_EMBEDDED_SERVER=1 -DENABLED_LOCAL_INFILE=1 -DWITH_INNOBASE_STORAGE_ENGINE=1
make && make install

chown -R mysql:mysql .
chmod +x scripts/mysql_install_db

./scripts/mysql_install_db --user=mysql --basedir=/usr/local/mysql --datadir=/data/mysql
cp ./support-files/mysql.server /etc/rc.d/init.d/mysqld
chmod 755 /etc/init.d/mysqld
chkconfig mysqld on

cat> /etc/rc.d/init.d/mysqld <<'EOF' #mysql startup script #!/bin/sh
# Copyright Abandoned 1996 TCX DataKonsult AB & Monty Program KB & Detron HB
# This file is public domain and comes with NO WARRANTY of any kind

# MySQL daemon start/stop script.

# Usually this is put in /etc/init.d (at least on machines SYSV R4 based
# systems) and linked to /etc/rc3.d/S99mysql and /etc/rc0.d/K01mysql.
# When this is done the mysql server will be started when the machine is
# started and shut down when the systems goes down.

# Comments to support chkconfig on RedHat Linux
# chkconfig: 2345 64 36
# description: A very fast and reliable SQL database engine.

# Comments to support LSB init script conventions
### BEGIN INIT INFO
# Provides: mysql
# Required-Start: $local_fs $network $remote_fs
# Should-Start: ypbind nscd ldap ntpd xntpd
# Required-Stop: $local_fs $network $remote_fs
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: start and stop MySQL
# Description: MySQL is a very fast and reliable SQL database engine.
### END INIT INFO

# If you install MySQL on some other places than /usr/local/mysql, then you
# have to do one of the following things for this script to work:
#
# - Run this script from within the MySQL installation directory
# - Create a /etc/my.cnf file with the following information:
# [mysqld]
# basedir=<path-to-mysql-installation-directory>
# - Add the above to any other configuration file (for example ~/.my.ini)
# and copy my_print_defaults to /usr/bin
# - Add the path to the mysql-installation-directory to the basedir variable
# below.
#
# If you want to affect other MySQL variables, you should make your changes
# in the /etc/my.cnf, ~/.my.cnf or other MySQL configuration files.

# If you change base dir, you must also change datadir. These may get
# overwritten by settings in the MySQL configuration files.
basedir=/usr/local/mysql
datadir=/data/mysql

# Default value, in seconds, after which the script should timeout waiting
# for server start. 
# Value here is overriden by value in my.cnf. 
# 0 means don't wait at all
# Negative numbers mean to wait indefinitely
service_startup_timeout=900

# Lock directory for RedHat / SuSE.
lockdir='/var/lock/subsys'
lock_file_path="$lockdir/mysql"

# The following variables are only set for letting mysql.server find things.

# Set some defaults
mysqld_pid_file_path=
if test -z "$basedir"
then
  basedir=/usr/local/mysql
  bindir=/usr/local/mysql/bin
  if test -z "$datadir"
  then
    datadir=/data/mysql/data
  fi
  sbindir=/usr/local/mysql/bin
  libexecdir=/usr/local/mysql/bin
else
 bindir="$basedir/bin"
  if test -z "$datadir"
  then
    datadir="$basedir/data"
  fi
  sbindir="$basedir/sbin"
  libexecdir="$basedir/libexec"
fi

# datadir_set is used to determine if datadir was set (and so should be
# *not* set inside of the --basedir= handler.)
datadir_set=
# Use LSB init script functions for printing messages, if possible
#
lsb_functions="/lib/lsb/init-functions"
if test -f $lsb_functions ; then
  . $lsb_functions
else
  log_success_msg()
  {
    echo " SUCCESS! $@"
  }
  log_failure_msg()
  {
    echo " ERROR! $@"
  }
fi

PATH="/sbin:/usr/sbin:/bin:/usr/bin:$basedir/bin"
export PATH
mode=$1 # start or stop

[ $# -ge 1 ] && shift


other_args="$*" # uncommon, but needed when called from an RPM upgrade action
           # Expected: "--skip-networking --skip-grant-tables"
           # They are not checked here, intentionally, as it is the resposibility
           # of the "spec" file author to give correct arguments only.

case `echo "testing\c"`,`echo -n testing` in
    *c*,-n*) echo_n= echo_c= ;;
    *c*,*) echo_n=-n echo_c= ;;
    *) echo_n= echo_c='\c' ;;
esac

parse_server_arguments() {
  for arg do
    case "$arg" in
      --basedir=*) basedir=`echo "$arg" | sed -e 's/^[^=]*=//'`
                    bindir="$basedir/bin"
                    if test -z "$datadir_set"; then
                      datadir="$basedir/data"
                    fi
                    sbindir="$basedir/sbin"
                    libexecdir="$basedir/libexec"
        ;;
      --datadir=*) datadir=`echo "$arg" | sed -e 's/^[^=]*=//'`
                    datadir_set=1
        ;;
      --pid-file=*) mysqld_pid_file_path=`echo "$arg" | sed -e 's/^[^=]*=//'` ;;
      --service-startup-timeout=*) service_startup_timeout=`echo "$arg" | sed -e 's/^[^=]*=//'` ;;
    esac
  done
}

wait_for_pid () {
  verb="$1" # created | removed
  pid="$2" # process ID of the program operating on the pid-file
pid_file_path="$3" # path to the PID file.

  i=0
  avoid_race_condition="by checking again"

  while test $i -ne $service_startup_timeout ; do

    case "$verb" in
      'created')
        # wait for a PID-file to pop into existence.
        test -s "$pid_file_path" && i='' && break
        ;;
      'removed')
        # wait for this PID-file to disappear
        test ! -s "$pid_file_path" && i='' && break
        ;;
      *)
        echo "wait_for_pid () usage: wait_for_pid created|removed pid pid_file_path"
        exit 1
        ;;
    esac

    # if server isn't running, then pid-file will never be updated
    if test -n "$pid"; then
 if kill -0 "$pid" 2>/dev/null; then
        : # the server still runs
      else
        # The server may have exited between the last pid-file check and now.  
        if test -n "$avoid_race_condition"; then
          avoid_race_condition=""
          continue # Check again.
                                         
        fi

        # there's nothing that will affect the file.
        log_failure_msg "The server quit without updating PID file ($pid_file_path)."
        return 1 # not waiting any more.
      fi
    fi

    echo $echo_n ".$echo_c"
    i=`expr $i + 1`
    sleep 1

  done

  if test -z "$i" ; then
    log_success_msg
    return 0
  else
    log_failure_msg
    return 1
  fi
}

# Get arguments from the my.cnf file,
# the only group, which is read from now on is [mysqld]
if test -x ./bin/my_print_defaults
then
  print_defaults="./bin/my_print_defaults"
elif test -x $bindir/my_print_defaults
then
  print_defaults="$bindir/my_print_defaults"
elif test -x $bindir/mysql_print_defaults
then
  print_defaults="$bindir/mysql_print_defaults"
else
  # Try to find basedir in /etc/my.cnf
  conf=/etc/my.cnf
  print_defaults=
  if test -r $conf
  then
    subpat='^[^=]*basedir[^=]*=\(.*\)$'
    dirs=`sed -e "/$subpat/!d" -e 's//\1/' $conf`
    for d in $dirs
    do
      d=`echo $d | sed -e 's/[ ]//g'`
      if test -x "$d/bin/my_print_defaults"
      then
        print_defaults="$d/bin/my_print_defaults"
        break
      fi
      if test -x "$d/bin/mysql_print_defaults"
      then
      print_defaults="$d/bin/mysql_print_defaults"
        break
      fi
    done
  fi
  # Hope it's in the PATH ... but I doubt it
  test -z "$print_defaults" && print_defaults="my_print_defaults"
fi

#
# Read defaults file from 'basedir'. If there is no defaults file there
# check if it's in the old (depricated) place (datadir) and read it from there
#

extra_args=""
if test -r "$basedir/my.cnf"
then
  extra_args="-e $basedir/my.cnf"
else
  if test -r "$datadir/my.cnf"
  then
    extra_args="-e $datadir/my.cnf"
  fi
fi

parse_server_arguments `$print_defaults $extra_args mysqld server mysql_server mysql.server`

#
# Set pid file if not given
#
if test -z "$mysqld_pid_file_path"
then
  mysqld_pid_file_path=$datadir/`hostname`.pid
else
  case "$mysqld_pid_file_path" in
    /* ) ;;
    * )mysqld_pid_file_path="$datadir/$mysqld_pid_file_path" ;;
  esac
fi

case "$mode" in
  'start')
    # Start daemon

    # Safeguard (relative paths, core dumps..)
    cd $basedir

    echo $echo_n "Starting MySQL"
    if test -x $bindir/mysqld_safe
    then
      # Give extra arguments to mysqld with the my.cnf file. This script
      # may be overwritten at next upgrade.
      $bindir/mysqld_safe --datadir="$datadir" --pid-file="$mysqld_pid_file_path" $other_args >/dev/null 2>&1 &
      wait_for_pid created "$!" "$mysqld_pid_file_path"; return_value=$?

      # Make lock for RedHat / SuSE
      if test -w "$lockdir"
      then
        touch "$lock_file_path"
      fi
  exit $return_value
    else
      log_failure_msg "Couldn't find MySQL server ($bindir/mysqld_safe)"
    fi
    ;;

  'stop')
    # Stop daemon. We use a signal here to avoid having to know the
    # root password.

    if test -s "$mysqld_pid_file_path"
    then
      mysqld_pid=`cat "$mysqld_pid_file_path"`

      if (kill -0 $mysqld_pid 2>/dev/null)
      then
        echo $echo_n "Shutting down MySQL"
        kill $mysqld_pid
        # mysqld should remove the pid file when it exits, so wait for it.
        wait_for_pid removed "$mysqld_pid" "$mysqld_pid_file_path"; return_value=$?
      else
        log_failure_msg "MySQL server process #$mysqld_pid is not running!"
        rm "$mysqld_pid_file_path"
      fi

      # Delete lock for RedHat / SuSE
      if test -f "$lock_file_path"
      then
        rm -f "$lock_file_path"
      fi
      exit $return_value
 else
      log_failure_msg "MySQL server PID file could not be found!"
    fi
    ;;

  'restart')
    # Stop the service and regardless of whether it was
    # running or not, start it again.
    if $0 stop $other_args; then
      $0 start $other_args
    else
      log_failure_msg "Failed to stop running server, so refusing to try to start."
      exit 1
    fi
    ;;

  'reload'|'force-reload')
    if test -s "$mysqld_pid_file_path" ; then
      read mysqld_pid < "$mysqld_pid_file_path"
      kill -HUP $mysqld_pid && log_success_msg "Reloading service MySQL"
      touch "$mysqld_pid_file_path"
    else
      log_failure_msg "MySQL PID file could not be found!"
      exit 1
    fi
    ;;
  'status')
    # First, check to see if pid file exists
    if test -s "$mysqld_pid_file_path" ; then
      read mysqld_pid < "$mysqld_pid_file_path"
      if kill -0 $mysqld_pid 2>/dev/null ; then
  log_success_msg "MySQL running ($mysqld_pid)"
        exit 0
      else
        log_failure_msg "MySQL is not running, but PID file exists"
        exit 1
      fi
    else
      # Try to find appropriate mysqld process
      mysqld_pid=`pidof $libexecdir/mysqld`
      if test -z $mysqld_pid ; then
        if test -f "$lock_file_path" ; then
          log_failure_msg "MySQL is not running, but lock file ($lock_file_path) exists"
          exit 2
        fi
        log_failure_msg "MySQL is not running"
        exit 3
      else
        log_failure_msg "MySQL is running but PID file could not be found"
        exit 4
      fi
    fi
    ;;
    *)
      # usage
      basename=`basename "$0"`
      echo "Usage: $basename {start|stop|restart|reload|force-reload|status} [ MySQL server options ]"
      exit 1
    ;;
                             
esac

exit 0
EOF

cat> /etc/my.cnf <<'EOF' #mysql configuration file [client]
#password = your_password
port = 3306
socket = /tmp/mysql.sock

# Here follows entries for some specific programs

# The MySQL server
[mysqld]
port = 3306
socket = /tmp/mysql.sock
skip-external-locking
key_buffer_size = 384M
max_allowed_packet = 64M
table_open_cache = 512
sort_buffer_size = 2M
read_buffer_size = 2M
read_rnd_buffer_size = 8M
myisam_sort_buffer_size = 64M
thread_cache_size = 8
query_cache_size = 32M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 8
basedir = /usr/local/mysql
datadir = /data/mysql
max_connections = 5000
long_query_time = 1
slow_query_log = 1
slow_query_log_file = /var/log/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!
lower_case_table_names = 1
# Replication Master Server (default)
# binary logging is required for replication
#log-bin=mysql-bin
skip-name-resolve
# 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
# binary logging - not required for slaves, but recommended
#log-bin=mysql-bin
#
# binary logging format - mixed recommended 
#binlog_format=mixed

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /data/mysql/data
#innodb_data_file_path = ibdata1:2000M;ibdata2:10M:autoextend
#innodb_log_group_home_dir = /data/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 = 4096M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
innodb_log_file_size = 512M
#innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 0
#innodb_lock_wait_timeout = 50

[mysqldump]
quick
max_allowed_packet = 64M

[mysql]
no-auto-rehash
# Remove the next comment character if you are not familiar with SQL
#safe-updates
[myisamchk]
key_buffer_size = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout

EOF

ln -s /usr/local/mysql/bin/mysqladmin /usr/bin
ln -s /usr/local/mysql/lib/mysql /usr/lib
ln -s /usr/local/mysql/include/mysql /usr/include/mysql
mkdir /var/lib/mysql
ln -s /tmp/mysql.sock /var/lib/mysql/mysql.sock
echo 'export PATH=$PATH:/usr/local/mysql/bin' >> /etc/profile
sleep 2
source /etc/profile

service mysqld start

sleep 5
cd /usr/local/mysql/bin && mysqladmin -uroot password 'mysql' #Authorize the root user's password
source /etc/profile

3. Master-slave configuration

1. Verify that the master database has data, and then authorize users with replication permissions

mysql> create database db1;
mysql> use db1
mysql> create table t1(id int, name varchar(12));
mysql> insert into t1 values(1, 'tom'), (2, 'jerry'), (3, 'jack');
mysql> grant replication slave,replication client on *.* to 'backuser'@'192.168.142.130' identified by 'mysqll';
mysql> grant replication slave,replication client on *.* to 'backuser'@'192.168.142.131' identified by 'mysql';
mysql> flush privileges;

2. Modify the configuration files of each database and restart the database

vi /etc/my.cnf #Main library configuration file server-id=1
log-bin=mysql-bin
binlog-do-db=db1
binlog-ignore-db=mysql 

vi /etc/my.cnf #Slave library configuration file server-id=2 #Slave library id cannot be the same as the master library, other slave libraries are arranged behind log-bin=relay-bin
replicate-do-db=db1 #Synchronize db1 database replicate-ignore-db=mysql #Do not synchronize mysql database read_only #Read only service mysqld restart

3. The master database locks the table for backup, and then transfers the file to the slave database

mysql> flush tables with read lock; #Lock the master table to prevent new data from being writtenmysql> show master status; #View the master location nodeOpen a new terminal backup:
mysqldump -u root -p --default-character-set=utf8 --opt -Q -R --skip-lock-tables db1 > /root/db1.sql  
scp /root/db1.sql [email protected]:/root   
scp /root/db1.sql [email protected]:/root

4. Import data from the database and then change to the node of the main database

mysql -u root -p
mysql> create database db1;
mysql> use db1
mysql> source /root/db1.sql
mysql> change master to master_host='192.168.142.129',master_user='backuser',master_password='mysql',master_log_file='mysql-bin.000001',master_log_pos=120;
mysql> start slave;
mysql> show slave status\G 

MySQL5.6 master-slave setup and master-slave asynchrony problem_Database_02

5. Unlock the main database

mysql> unlock tables;

The above configuration is also applicable to reconfiguring the master and slave when the master and slave are out of sync.

4. Master-slave asynchrony

1. Causes of asynchrony

Network delay Inconsistent load on the master and slave machines Inconsistent max_allowed_packet settings Inconsistent key value and auto-increment step settings causing master-slave inconsistency In the case of abnormal mysql downtime, if sync_binlog=1 or innodb_flush_log_at_trx_commit=1 is not set, it is very likely

The binlog or relaylog file is damaged, resulting in inconsistency between the master and slave. The master and slave are out of sync due to a bug in MySQL itself. Inconsistent versions, especially when the higher version is the master and the lower version is the slave. The function supported on the master database is not supported on the slave database.

2. Solution

(1) Ignore the error and continue synchronization

This method is suitable for situations where the data of the master and slave databases are not very different, or the data can be not completely unified, and the data requirements are not strict.

stop slave;
set global sql_slave_skip_counter = 1;
start slave;
show slave status\G

(2) Re-establishing the master-slave relationship

Refer to the above configuration to lock the master database table and make it a master-slave again.

This is the end of this article about the detailed explanation of MySQL 5.6 master-slave construction and asynchrony issues. For more information about MySQL master-slave construction and asynchrony, please search for previous articles on 123WORDPRESS.COM or continue to browse the following related articles. I hope you will support 123WORDPRESS.COM in the future!

You may also be interested in:
  • Implementation steps of mysql master-slave replication
  • MySQL master-slave synchronization principle and application
  • Analysis of the Principle and Function of MySQL Database Master-Slave Replication

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