按月轉(zhuǎn)移日志表中日志時，mysql總是報‘MySQL server has gone away’這樣的錯！

我有一段清除數(shù)據(jù)庫日志的腳用來按月清除數(shù)據(jù)庫中的日志文件然后再把它們按月分表存儲，腳本平時運行正常但是每到月初一定會報一次‘MySQL server has gone away’這樣的錯，不知道為什么！
腳本代碼如下：

class PaizuTableHandler extends ScriptBase
{
    public static $mysql = null;
    const LOG_PAIZU_TABLE = 'log_user_paiju';
    public function logic()
    {
        if(empty(self::$mysql)){
            self::$mysql = $this->mysql('logs');
        }
        set_time_limit(0);
        while (true)
        {
            $date = date("Y-m-d");
            $dataTime =  strtotime($date);

            $timestampStart = $dataTime - 3600*24; //昨天
            $timestampEnd = mktime(0,0,0,date("m"),1,date("Y"));//本月月初 例如：2017-07-01 00:00:00
            $timestampEnd_lastmoth = mktime(0, 0 , 0,date("m")-1,1,date("Y"));//上月月初 例如：2017-06-01 00:00:00
            $transferLastMonth = mktime(0,0,0,date("m"),5,date("Y")); //月初第5天(轉(zhuǎn)移上月數(shù)據(jù))

            if($timestampStart < $timestampEnd){
                sleep(60);
                continue;
            }

            $table = self::LOG_PAIZU_TABLE.'_'.date("Ym");//本月的表
            $lastMothTable = self::LOG_PAIZU_TABLE.'_'.date("Ym",mktime(0, 0 , 0,date("m")-1,1,date("Y")));//上個月的表
            $hasTable = self::$mysql->tableExists($table);  //判斷是否有本月的表
            $hasTableLast = self::$mysql->tableExists($lastMothTable);  //判斷是否有上個月的表
            $createFlag = $hasTable ? true : false; //本月的表是否存在
            $createFlagLast = $hasTableLast ? true : false; //上個月的表是否存在
            if( empty( $createFlag ) ){
                try {
                    //創(chuàng)建表
                    $createSql = "CREATE TABLE {$table} LIKE log_user_paiju";
                    $ret = self::$mysql->query($createSql);
                    if(!$ret){
                        //拋出異常
                        $errorMessage =  self::$mysql -> error_no() . ": " . self::$mysql ->error();
                        throw new Exception($errorMessage);
                    }

                } catch(Exception $ex) {
                    echo 'TIME:'.date("Y-m-d H:i:s")."\n";
                    echo 'TIME_START~TIME_END:'.date("Y-m-d H:i:s",$timestampStart)."~".date("Y-m-d H:i:s",$timestampEnd)."\n";
                    $msg = 'Error:'.$ex->getMessage()."\n";
                    $msg.= $ex->getTraceAsString()."\n";
                    $msg.= '異常行號：'.$ex->getLine()."\n";
                    $msg.= '所在文件：'.$ex->getFile()."\n";
                    //將異常信息記錄到日志中PHP異常處理之
                    echo $msg;
                    echo "\n";
                    break;
                }
            }

            if( $createFlag ){

                try {
                    //查詢本月當天應清空數(shù)據(jù)有沒有清空
                    $sql = "select * from log_user_paiju where UNIX_TIMESTAMP(`time`) between {$timestampEnd} and {$timestampStart} order by `time` desc limit 100";
                    $result = self::$mysql->query($sql);
                    $rs = self::$mysql -> fetch_row($result);
                    if( !$result ){
                        //拋出異常
                        $errorMessage =  self::$mysql -> error_no() . ": " . self::$mysql ->error();
                        throw new Exception($errorMessage);
                    }

                    //處理上月數(shù)據(jù)（本月第5天把 上個月的數(shù)據(jù)全部放到上個月的表中（要放最少2天前））
                    $last_rs = array();
                    if($dataTime == $transferLastMonth && !empty( $createFlagLast ) && empty($rs)){
                        $last_sql = "select * from log_user_paiju where UNIX_TIMESTAMP(`time`) between {$timestampEnd_lastmoth} and {$timestampEnd} order by `time` desc limit 100";
                        $last_sql1 = "INSERT INTO {$lastMothTable}(uid,paiju_score,paizu_score,`time`,paizu_id,seq,room_id,server_id,creator,`status`,mahjongType,cid) SELECT uid,paiju_score,paizu_score,`time`,paizu_id,seq,room_id,server_id,creator,`status`,mahjongType,cid FROM log_user_paiju where UNIX_TIMESTAMP(`time`) between {$timestampEnd_lastmoth} and {$timestampEnd} order by `time` desc limit 100";
                        $last_sql2 = "delete from log_user_paiju where UNIX_TIMESTAMP(`time`) between {$timestampEnd_lastmoth} and {$timestampEnd} order by `time` desc limit 100";
                        $result1 = self::$mysql->query($last_sql);
                        //var_dump($result1);
                        if(!$result1){
                            //拋出異常
                            $errorMessage =  self::$mysql -> error_no() . ": " . self::$mysql ->error();
                            throw new Exception($errorMessage);
                        }

                        $last_rs = self::$mysql -> fetch_row($result1);
                        if($last_rs){
                            if($r = self::$mysql->query($last_sql1)){
                                self::$mysql->query($last_sql2);
                            }else{
                                //拋出異常
                                $errorMessage =  self::$mysql -> error_no() . ": " . self::$mysql ->error();
                                throw new Exception($errorMessage);
                            }
                        }

                    }

                    //處理本月數(shù)據(jù)
                    $sql1 = "INSERT INTO {$table}(uid,paiju_score,paizu_score,`time`,paizu_id,seq,room_id,server_id,creator,`status`,mahjongType,cid) SELECT uid,paiju_score,paizu_score,`time`,paizu_id,seq,room_id,server_id,creator,`status`,mahjongType ,cid FROM log_user_paiju where UNIX_TIMESTAMP(`time`) between {$timestampEnd} and {$timestampStart} order by `time` desc limit 100";
                    $sql2 = "delete from log_user_paiju where UNIX_TIMESTAMP(`time`) between {$timestampEnd} and {$timestampStart} order by `time` desc limit 100";

                    if(empty($rs) && empty($last_rs)){
                        sleep(60);
                    }
                    if($rs){
                        if($r1=self::$mysql->query($sql1)){
                            !self::$mysql->query($sql2);
                        }else{
                            //拋出異常
                            $errorMessage =  self::$mysql -> error_no() . ": " . self::$mysql ->error();
                            throw new Exception($errorMessage);
                        }
                    }

                } catch(Exception $ex) {
                    echo 'TIME:'.date("Y-m-d H:i:s")."\n";
                    echo 'TIME_START~TIME_END:'.date("Y-m-d H:i:s",$timestampStart)."~".date("Y-m-d H:i:s",$timestampEnd)."\n";
                    $msg = 'Error:'.$ex->getMessage()."\n";
                    $msg.= $ex->getTraceAsString()."\n";
                    $msg.= '異常行號：'.$ex->getLine()."\n";
                    $msg.= '所在文件：'.$ex->getFile()."\n";
                    //將異常信息記錄到日志中PHP異常處理之
                    echo $msg;
                    echo "\n";
                    break;
                }

            }
            usleep(3000);
        }
    }

}

shell腳本如下：

#!/bin/sh
# scripts daemon, add to /etc/crontab
# */1 *   *   *   *   root    PATH/script.sh --daemon

# run on root
if [ "$(uname -s|grep -F 'CYGWIN')" = "" ] && [ $UID -ne 0 ]; then
    echo "superuser privileges are required to run this script."
    exit 1
fi

# settings
PHP_CLI="/usr/bin/php -c /usr/local/php/etc/php.ini"
SCRIPTS="PaijuLogHandler PaijuTableHandler PaizuTableHandler ClubDiamondLogHandler"

# paths
BASE_PATH=$(cd $(dirname $0) && pwd)
BASE_SCRIPT="$BASE_PATH/script.php"
LOGS_PATH="$BASE_PATH/data/logs/bash.log"

USAGE="Usage: $(basename $0) [-d|-a|-k SCRIPT]\n\
  -d, --daemon\t\tthe daemon mode, runing checking\n\
  -a, --killall\t\tkill the all scripts\n\
  -k, --kill SCRIPT\tkill the SCRIPT\n\
  -h, --help\t\tthis help text"

function get_pid()
{
    echo $(ps -ef|grep -F "$1"|grep -v "grep"|awk '{print $2}')
}

function kill_script()
{
    PID=$(get_pid "$1")
    if [ "$PID" = "" ]; then
        echo "$1 not found"
    else
        kill -9 $PID
        echo "$1 has been killed, pid: $PID"
    fi
}

case $1 in
    -k|--kill)
        if [ "$2" = "" ]; then
            echo -e $USAGE
            exit 0
        fi
        kill_script "$BASE_SCRIPT request/$2"
        ;;
    -a|--killall)
        for SCRIPT in $SCRIPTS; do
            kill_script "$BASE_SCRIPT request/$SCRIPT"
        done
        ;;
    -d|--daemon)
        for SCRIPT in $SCRIPTS; do
            SCRIPT="$BASE_SCRIPT request/$SCRIPT"
            PID=$(get_pid "$SCRIPT")
            if [ "$PID" = "" ]; then
                eval "$PHP_CLI $SCRIPT >>/data/logs/scriptlog/log.txt 2>&1 &"
                PID=$(get_pid "$SCRIPT")
                echo "[$(date +%Y-%m-%d\ %H:%M:%S)] $SCRIPT has been down, restarted: $PID" >> $LOGS_PATH
            fi
        done
        ;;
    *)
        echo -e $USAGE
        ;;
esac

報錯如下：
TIME:2018-02-02 00:00:48
Error:2006: MySQL server has gone away