从shell脚本执行时关闭mysql连接

Question

Using shell script to run mysql insert query, while running the query i am seeing connections are not being closed from shell script.

Server Response after running the shell script

$ date
Tue Feb 20 15:43:58
$ netstat -alnp | grep 3306 | wc -l
26 

Where above 26 counts were like

tcp6       0      0 192.168.10.169:31503      192.168.10.170:3306 ESTABLISHED 11603/java
$ netstat -alnp | grep 3306 | wc -l
50

Where above 50 counts were like (TIME_WAIT - 22) and (ESTABLISHED - 28)

tcp6       0      0 192.168.10.169:48308      192.168.10.170:3306 ESTABLISHED 12603/java   
tcp6       0      0 192.168.10.169:48990      192.168.10.170:3306 TIME_WAIT
$ date
Tue Feb 20 15:46:49

1. Does mysql connection ran through shell script doesn't get closed by self
2. What is greater impact if shell script with mysql insert command ran via cron job at every 30 minutes

Script

#!bin/bash
query="insert into table_name values ('foo', 'bar' , 123, NOW() )where column_name is NOT NUll"

mysql -u username -p password mysql  <<EOF
$query;
EOF

What will be impact on mysql maximum connections, While ran to my system i got more than 100 connections ESTABLISHED

Answer 1

What STATUS value corresponds to connections ESTABLISHED ?

What was the value of

`SHOW GLOBAL STATUS LIKE 'Max_used_connections';

I expect a small number like 1 or 2.

For

`SHOW GLOBAL STATUS LIKE 'Connections';

I expect over 100.

The commandline tool mysql will create a connection (bumping Connections and possibly increasing the "high water mark" for Max_used_connections ), do the action, then close the connection (without decreasing any STATUS ). Threads_running is also incremented and decremented.

Your cron job should not be threatening any limitations.