SELECT
cast( pow(2, case data_type
  when 'tinyint'  then 7
  when 'smallint' then 15
  when 'mediumint' then 23
  when 'int'    then 31
  when 'bigint'  then 63
  end+(column_type like '% unsigned'))-1 as decimal(30,0)) as max_int,
' - ',
concat ('(', concat('select ','max(',COLUMN_NAME,')',' from ',TABLE_SCHEMA,'.',TABLE_NAME),')') 
from
information_schema.COLUMNS
where
TABLE_SCHEMA NOT IN ('information_schema','sys','test','mysql','performance_schema')
AND
 DATA_TYPE IN ('int' ) ;

#!/bin/bash
# 监测int类型的当可用空间少500w的时候，提醒做DDL操作
# 设置 session级别的 max_execution_time为2秒，防止没有索引的大的拖慢数据库，但是这样可能漏判部分列，需要注意下
# 注意：我这里bigint类型的没有检查，如果需要请修改 check.sql where条件中的DATA_TYPE加上 bigint的检查

source /etc/profile
set -u

mkdir $(date +%F) -pv

# step1 检测
for host in {'192.168.1.100','192.168.1.110','192.168.1.120','192.168.1.130'}; do

mysql -udts -pdts -h${host} -BN < check.sql  2>/dev/null > sql.log
wait

echo "说明： | 当前列允许的最大值 | 巡检用的SQL   " >> $(date +%F)/$host.log

while read line; do
  ret=$(mysql -udts -pdts -h${host} -BNe "set session max_execution_time=2000;select $line" 2>/dev/null)
  echo ${ret}
  if [[ "${ret}" == "NULL" ]]; then
  continue
  fi
  if [ ${ret} -lt 5000000 ] ; then
   echo "$line 剩余空间 ${ret}, 该表可用水位不足500W，建议做DDL修改为bigint类型" >> $(date +%F)/$host.log
  
  fi
done < ./sql.log

done

# step2 将检查的内容打包发邮件（这里可能需要根据自己生产的情况改改）
tar czf $(date +%F).tar.gz $(date +%F)
sendemail -s 192.168.1.200 -f post@domain.com -t ergou@domain.com -a $(date +%F).tar.gz -u "$(date +%F) int水位线巡检日志" -o message-content-type=html -o message-charset=utf8 -m "内容详见附件"

# step3 清理每日生成的以日期命名的目录和tar.gz文件，这里我就不贴命令