Detailed explanation of non-primary key column overflow monitoring in MySQL tables

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
# Monitor int type. When the available space is less than 5 million, remind to do DDL operation. # Set max_execution_time of session level to 2 seconds to prevent large columns without index from slowing down the database. However, this may miss some columns, so please pay attention. # Note: I have not checked bigint type here. If necessary, please modify DATA_TYPE in check.sql where condition to add bigint check source /etc/profile
set -u

mkdir $(date +%F) -pv

# step1 detection 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 "Description: | Maximum value allowed for the current column | SQL for inspection " >> $(date +%F)/$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 remaining space ${ret}, the table available water level is less than 5 million, it is recommended to modify the DDL to bigint type" >> $(date +%F)/$host.log
  
  fi
done < ./sql.log

done

# step2 Package the inspection contents and send them by email (you may need to modify this according to your production situation)
tar czf $(date +%F).tar.gz $(date +%F)
sendemail -s 192.168.1.200 -f [email protected] -t [email protected] -a $(date +%F).tar.gz -u "$(date +%F) int water level inspection log" -o message-content-type=html -o message-charset=utf8 -m "For details, please see the attachment"

# step3 clean up the date-named directories and tar.gz files generated daily. I won’t post the commands here.