mysql從庫掛掉，記下master節點然後匯出資料庫，匯入到從庫伺服器，最後修改slave的master資訊，有時候直接就好了，如果沒有好，比如匯出的時候主節點添加了很多資料，導致pos變掉了，當然會變，畢竟沒有停止資料庫。如果沒有好用下面的指令碼，執行下，跳過重複的資料就ok了

change master to master_host='111.111.111.111',master_user='slave_site',master_password='password', master_log_file='mysql-bin.000520',master_log_pos=146851479;

mysql_slave_skip.pl

#!/usr/bin/env perl
use strict;
use warnings;

# get slave status
sub get_status {
    my ($ip, $usr, $pass) = @_;
    my $info = `mysql -u$usr -p$pass -h$ip -e 'show slave status\\G;'`;
    if (($info =~ /Slave_IO_Running: Yes/) && ($info =~ /Slave_SQL_Running: No/)) {
        return 1;
    }
    return
 
 0;
}
# mysql slave skip
sub slaveskip {
    my ($ip, $usr, $pass) = @_;
    print "slave error **\n";
    system("mysql -u$usr -p$pass -h$ip -e 'slave stop;'");
    system("mysql -u$usr -p$pass -h$ip -e 'set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;'");
    system("mysql -u$usr -p$pass -h$ip -e 'slave start;'"
 
);
}

sub stopslave {
    my ($ip, $usr, $pass) = @_;
    print "stop slave\n";
    system("mysql -u$usr -p$pass -h$ip -e 'slave stop;'");
}

my @hosts = qw/
localhost:root:A3NWgX4WQ4m22KvMU2a3Vc2vQ
/;
foreach (@hosts) {
    my ($ip, $usr, $pass) = split ':';
    print "// ----- $ip\n";
    my $oktimes=0;
    my $count = 1;
    while ($count < 100000) {
        my $status = get_status($ip, $usr, $pass);
        if($status==0){
            $oktimes++;
            if($oktimes<50){
                select(undef, undef, undef, 0.1);
                $count++;
                next;
            }
            else{
                print "i: $count status: $status\n";
                #stopslave($ip, $usr, $pass);
                last;
            }
        }
        else{
        print "i: $count status: $status\n";
        $oktimes=0;
            slaveskip($ip, $usr, $pass);
            select(undef, undef, undef, 0.1);
            $count++;
        }
    }
    print "\n";
}

exit;