Mysql interactive_ Timeout and wait_ Timeout differences

Mysql interactive_timeout and wait_timeout The difference between

In use mysql When the client operates the database , Open terminal window , If there is no operation for a period of time , When operating again , The following mistakes are often reported ：

ERROR 2013 (HY000): Lost connection to MySQL server during query ERROR
2006 (HY000): MySQL server has gone away No connection. Trying to
reconnect…

This error message means that the current connection has been disconnected , The connection needs to be reestablished .

that , How to confirm the connection duration ？

Actually , This with interactive_timeout and wait_timeout The settings of .

First , Take a look at the official document definition of these two parameters

interactive_timeout

The default is 28800, Unit second , namely 8 Hours

The number of seconds the server waits for activity on an interactive
connection before closing it. An interactive client is defined as a
client that uses the CLIENT_INTERACTIVE option to
mysql_real_connect(). See also wait_timeout.

wait_timeout

The default is the same 28800s

The number of seconds the server waits for activity on a
noninteractive connection before closing it.

On thread startup, the session wait_timeout value is initialized from
the global wait_timeout value or from the global interactive_timeout
value, depending on the type of client (as defined by the
CLIENT_INTERACTIVE connect option to mysql_real_connect()). See also
interactive_timeout.

According to the above definition , The difference between the two is obvious

1> interactive_timeout For interactive connections ,wait_timeout For non interactive connections . So called interactive connection , That is to say mysql_real_connect() Used in function CLIENT_INTERACTIVE Options .

  To be frank , adopt mysql The client connection to the database is an interactive connection , adopt jdbc Connecting to a database is a non interactive connection . 

2> When the connection starts , Depending on the type of connection , To confirm the session variables wait_timeout The value of is inherited from the global variable wait_timeout, still interactive_timeout.

Let's test it , Confirm the following questions

1. Which parameter controls the maximum idle time of the connection .

2. Session variables wait_timeout The question of inheritance

Q1： Which parameter controls the maximum idle time of the connection

A1：wait_timeout

verification

Modify only wait_timeout Parameters

mysql> select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout');
+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 28800          |
| WAIT_TIMEOUT        | 28800          |
+---------------------+----------------+
2 rows in set (0.03 sec)

mysql> set session WAIT_TIMEOUT=10;
Query OK, 0 rows affected (0.00 sec)
------- wait for 10s Post execution 
mysql> select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout');
ERROR 2013 (HY000): Lost connection to MySQL server during query

You can see , wait for 10s Then perform the operation , The connection has been disconnected .

Modify only interactive_timeout Parameters

mysql> select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout');
+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 28800          |
| WAIT_TIMEOUT        | 28800          |
+---------------------+----------------+
2 rows in set (0.06 sec)

mysql> set session INTERACTIVE_TIMEOUT=10;
Query OK, 0 rows affected (0.00 sec)
---------- wait for 10s After execution 
mysql> select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout');
+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 10             |
| WAIT_TIMEOUT        | 28800          |
+---------------------+----------------+
2 rows in set (0.06 sec)

Q2： Session variables wait_timeout The question of inheritance

A2： If it's an interactive connection , Then inherit the global variable interactive_timeout Value , If it's a non interactive connection , Then inherit the global variable wait_timeout Value .

verification ：

Modify only global variables interactive_timeout Value

mysql> select variable_name,variable_value from information_schema.global_variables where variable_name in ('interactive_timeout','wait_timeout'); 
+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 28800          |
| WAIT_TIMEOUT        | 28800          |
+---------------------+----------------+
2 rows in set (0.13 sec)

mysql> set global INTERACTIVE_TIMEOUT=10;
Query OK, 0 rows affected (0.00 sec)

mysql> select variable_name,variable_value from information_schema.global_variables where variable_name in ('interactive_timeout','wait_timeout');
+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 10             |
| WAIT_TIMEOUT        | 28800          |
+---------------------+----------------+
2 rows in set (0.00 sec)

Open another mysql client , Look at the value of the session variable

mysql> select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout');
+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 10             |
| WAIT_TIMEOUT        | 10             |
+---------------------+----------------+
2 rows in set (0.00 sec)

Find out ,WAIT_TIMEOUT The value of has changed to 10 了 .

But through jdbc test ,wait_timeout The value of is still 28800

public class Jdbc_test {
    
    @SuppressWarnings("static-access")
    public static void main(String[] args) throws Exception {
    
         Connection conn = null;
         Statement stmt = null;
         ResultSet rs = null;
         String url = "jdbc:mysql://192.168.244.10:3306/test";
         String user = "root";
         String password = "123456";
         Class.forName("com.mysql.jdbc.Driver");
         conn = DriverManager.getConnection(url, user, password);
         stmt = conn.createStatement();
         String sql = "select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout')";
         rs = stmt.executeQuery(sql);
         while (rs.next()) {
    
             System.out
                     .println(rs.getString(1)+": "+rs.getString(2));
         }
    }
}

The output is as follows ：
INTERACTIVE_TIMEOUT: 10
WAIT_TIMEOUT: 28800

Modify only global variables wait_timeout Value

mysql> select variable_name,variable_value from information_schema.global_variables where variable_name in ('interactive_timeout','wa it_timeout');+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 28800          |
| WAIT_TIMEOUT        | 28800          |
+---------------------+----------------+
2 rows in set (0.17 sec)

mysql> set global WAIT_TIMEOUT=20;
Query OK, 0 rows affected (0.07 sec)

mysql> select variable_name,variable_value from information_schema.global_variables where variable_name in ('interactive_timeout','wa it_timeout');+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 28800          |
| WAIT_TIMEOUT        | 20             |
+---------------------+----------------+
2 rows in set (0.00 sec)

Open another mysql client , Look at the value of the session variable

mysql> select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout');
+---------------------+----------------+
| variable_name       | variable_value |
+---------------------+----------------+
| INTERACTIVE_TIMEOUT | 28800          |
| WAIT_TIMEOUT        | 28800          |
+---------------------+----------------+
2 rows in set (0.03 sec)

WAIT_TIMEOUT The value of is still 28800.

see jdbc Result

public class Jdbc_test {
    
    @SuppressWarnings("static-access")
    public static void main(String[] args) throws Exception {
    
         Connection conn = null;
         Statement stmt = null;
         ResultSet rs = null;
         String url = "jdbc:mysql://192.168.244.10:3306/test";
         String user = "root";
         String password = "123456";
         Class.forName("com.mysql.jdbc.Driver");
         conn = DriverManager.getConnection(url, user, password);
         stmt = conn.createStatement();
         String sql = "select variable_name,variable_value from information_schema.session_variables where variable_name in ('interactive_timeout','wait_timeout')";
         rs = stmt.executeQuery(sql);
         while (rs.next()) {
    
             System.out
                     .println(rs.getString(1)+": "+rs.getString(2));
         }
         Thread.currentThread().sleep(21000);
         sql = "select 1 from dual";
         rs = stmt.executeQuery(sql);
         while (rs.next()) {
    
             System.out
                     .println(rs.getInt(1));
         }

    }
}

see jdbc Result

INTERACTIVE_TIMEOUT: 28800
WAIT_TIMEOUT: 20
meanwhile , A new program has been added , wait for 20s after , Execute the query again , Report the following error ：

Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Last packet sent to the server was 12 ms ago.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3009)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2895)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3438)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1951)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2101)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2548)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2477)
    at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1422)
    at com.victor_01.Jdbc_test.main(Jdbc_test.java:29)
Caused by: java.net.SocketException: Software caused connection abort: recv failed
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.socketRead(Unknown Source)
    at java.net.SocketInputStream.read(Unknown Source)
    at java.net.SocketInputStream.read(Unknown Source)
    at com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
    at com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
    at com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:188)
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:2452)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2906)
    ... 8 more

summary

1. Control the maximum idle time of the connection wait_timeout Parameters .

2. For non interactive connections , Be similar to jdbc Connect ,wait_timeout The value of is inherited from the server-side global variable wait_timeout.

   For interactive connections , Be similar to mysql Customer single connection ,wait_timeout The value of is inherited from the server-side global variable interactive_timeout.

3. Determine the idle time of a connection , It can be done by show processlist Output in progress Sleep Time of state

mysql> show processlist;
+----+------+----------------------+------+---------+------+-------+------------------+
| Id | User | Host                 | db   | Command | Time | State | Info             |
+----+------+----------------------+------+---------+------+-------+------------------+
|  2 | root | localhost            | NULL | Query   |    0 | init  | show processlist |
|  6 | repl | 192.168.244.20:44641 | NULL | Sleep   | 1154 |       | NULL             |
+----+------+----------------------+------+---------+------+-------+------------------+
2 rows in set (0.03 sec)