mysql连接超时的最佳解决方案是什么?

I am writing a small web app in Go, which uses mysql to store data.

I got intermittent mysql error if the web sever didn't get any request after some amount of time(> 8 hours):

[mysql] 2017/02/08 16:31:56 packets.go:33: unexpected EOF
[mysql] 2017/02/08 16:31:56 packets.go:130: write tcp 127.0.0.1:49188->127.0.0.1:3306: write: broken pipe

I found some related discussion on github(issue 529, issue 257 and issue 446). From what I understand, mysql db would close the connection if timeout is reached.

I tried to set SetMaxOpenConns to 9 and SetMaxIdleConns to 0 as some people recommended. However, this threw exception immediately. (But if I set SetMaxIdleConns larger than 0, there was no immediate exception thrown)

I also tried to set SetConnMaxLifetime to 5 mins. This threw exception too after 5 mins.

Now I am trying the code below:

db.SetConnMaxLifetime(0)
db.SetMaxOpenConns(10)
db.SetMaxIdleConns(5)

It has been running for 20 mins. It's still too early to tell. (UPDATE: this doesn't work either)

Here is configuration:

  • driver: go-sql-driver V1.3.
  • go version: go1.7.1 darwin/amd64
  • mysql: latest from docker hub
  • rkt version: 1.18
  • CoreOS: 1284.0.0

2个回答

  1. you can check your mysql time_wait variable:

    mysql> show global variables like 'wait_timeout':
    +---------------+-------+
    | Variable_name | Value |
    +---------------+-------+
    | wait_timeout  | 300   |
    +---------------+-------+
    1 row in set (0.00 sec)
    
  2. then use db.SetConnMaxLifetime(120*time.Second), which mean when db connection is idle over than 120s, sql.db will reopen or get a new connection from db pool by db.Open. If you not set connection max life time, you maybe use a closed connection and got the error.

  3. watching the mysql process list,mysql> show processlist;,if connection sleep over than 300s,it's recycled by mysql:

    mysql> show processlist;
    +-------+-----------------+------------------+-------------+---------+---------+------------------------+------------------+
    | Id    | User            | Host             | db          | Command | Time    | State                  | Info             |
    +-------+-----------------+------------------+-------------+---------+---------+------------------------+------------------+
    |     4 | event_scheduler | localhost        | NULL        | Daemon  | 1363480 | Waiting on empty queue | NULL             |
    | 26539 | root            | 172.17.0.1:48732 | NULL        | Query   |       0 | starting               | show processlist |
    | 26575 | auditcenter     | 172.17.0.1:51714 | obs_gb_test | Sleep   |      51 |                        | NULL             |
    +-------+-----------------+------------------+-------------+---------+---------+------------------------+------------------+
    3 rows in set (0.00 sec)
    
  4. SetMaxOpenConns and SetMaxIdleConns is used for setting connection resource, see enter link description here



也许您可以启动心跳Goroutine以避免超时。</ p>
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原文

Perhaps you can start a heartbeat Goroutine to avoid timeout.

dou760663
dou760663 是的,使用股票行情是一个好主意。 感谢您的建议。
3 年多之前 回复
doujunchi1238
doujunchi1238 可能需要及时处理。股票代号,不需要尽可能快地ping通。
3 年多之前 回复
dqysi86208
dqysi86208 也许在github.com/go-sql-driver/mysql/issues/498中给出建议,{for {db.Exec(“ DO 42”)}}会更好
3 年多之前 回复
dongnao1908
dongnao1908 对于{db.ping()}来说,作为心跳goroutine足够好了吗?
3 年多之前 回复
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