dlslaved 0.1

(Delayed Slave Daemon for MySQL)

allows delayed replication for MySQL databases.

The

syntax is really simple :

   -> dlslaved -h ipAddress -u username -p password -P portNumber

• 11/06/2007 : initial release
Well, it's done. I finally put the source code on Internet. So, be gentle. It's my first unix program.
The internal architecture of dlslaved is very simple. It uses the SecondsBehindMaster MySQL internal variable, and the STOP and START slave command to try to have 7200 seconds (a constant in the program) constantly behind the master.
Try it, use it, send back errors and source modifications.

It compiles under Linux and Solaris (x86 and Sparc) using gcc.

Download dlslaved user's manual (a PDF file).
Download dlslaved source code for Linux and Solaris (i think most Unix like systems). To compile, you need MySQL binaries and libraries to be install in /usr/local/mysql directory.

Contact me at rodolphe.jouannet(at)free.fr for support or questions.

根据上述思路，写一shell来实现相同的操作：

#!/bin/bash 
# 
# 监控mysql slave状态，实现slave延时 
# 
INTERVAL="1800" 
#CURPATH=$(pwd) 
CURPATH=/home/adminshell 
AUTH='-uroot -ppassword' 
SLAVE_IO="Slave_IO_Running:" 
SLAVE_SQL="Slave_SQL_Running:" 
SHOW_SLAVE_STATUS="show slave status\G" 
START_SLAVE="start slave" 
STOP_SLAVE="stop slave" 
 
MYSQL="$(which mysql)" 
if [ $? -ge 1 ] 
then 
    MYSQL="/usr/local/mysql/bin/mysql" 
fi 
 
PIDOF="$(which pidof)" 
if [ $? -ge 1 ] 
then 
    PIDOF="/sbin/pidof" 
fi 
 
while : 
do 
    TIMESTAMP_TODAY="$(date +%Y%m%d)" 
    LOGFILE="${CURPATH}/mysql_slave_delay_${TIMESTAMP_TODAY}.log" 
    echo "[`date +%c`] mysqld process check" >> $LOGFILE 
    MYSQLDPID=$($PIDOF mysqld) 
    if [ -z $MYSQLDPID ];then 
        echo "mysqld is not started!" >> $LOGFILE 
    else 
        echo "[`date +%c`] mysqld is running" >> $LOGFILE 
        echo "[`date +%c`] mysql slave status check" >> $LOGFILE 
        SLAVE_IO_STATUS=$($MYSQL $AUTH -Bse "$SHOW_SLAVE_STATUS" | grep $SLAVE_IO | awk '{ print $2 }') 
        SLAVE_SQL_STATUS=$($MYSQL $AUTH -Bse "$SHOW_SLAVE_STATUS" | grep $SLAVE_SQL | awk '{ print $2 }') 
        if [ "$SLAVE_IO_STATUS" = "Yes" -a "$SLAVE_SQL_STATUS" = "Yes" ];then 
            echo "[`date +%c`] mysql slave is running,stop it" >> $LOGFILE 
            $MYSQL $AUTH -Bse "$STOP_SLAVE" 
        else 
            echo "[`date +%c`] mysql slave is not running,start it" >> $LOGFILE 
            $MYSQL $AUTH -Bse "$START_SLAVE" 
        fi 
        echo "[`date +%c`] ****************************************************" >> $LOGFILE 
        sleep ${INTERVAL} 
    fi 
done