MySQL中interactive_timeout和wait_timeout的區別 轉

原創 彬彬公子 2018-12-02 21:05

在用mysql客戶端對數據庫進行操作時，打開終端窗口，如果一段時間沒有操作，再次操作時，常常會報如下錯誤：

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ERROR 2013 (HY000): Lost connection to MySQL server during query

ERROR 2006 (HY000): MySQL server has gone away

No connection. Trying to reconnect...

這個報錯信息就意味着當前的連接已經斷開，需要重新建立連接。

那麼，連接的時長是如何確認的？

其實，這個與interactive_timeout和wait_timeout的設置有關。

首先，看看官方文檔對於這兩個參數的定義

interactive_timeout

默認是28800，單位秒，即8個小時

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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

默認同樣是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.

根據上述定義，兩者的區別顯而易見

1> interactive_timeout針對交互式連接，wait_timeout針對非交互式連接。所謂的交互式連接，即在mysql_real_connect()函數中使用了CLIENT_INTERACTIVE選項。

說得直白一點，通過mysql客戶端連接數據庫是交互式連接，通過jdbc連接數據庫是非交互式連接。

2> 在連接啓動的時候，根據連接的類型，來確認會話變量wait_timeout的值是繼承於全局變量wait_timeout，還是interactive_timeout。

下面來測試一下，確認如下問題

1. 控制連接最大空閒時長的是哪個參數。

2. 會話變量wait_timeout的繼承問題

Q1：控制連接最大空閒時長的是哪個參數

A1：wait_timeout

驗證

只修改wait_timeout參數

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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)

-------等待10s後再執行

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

可以看到，等待10s後再執行操作，連接已經斷開。

只修改interactive_timeout參數

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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)

----------等待10s後執行

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：會話變量wait_timeout的繼承問題

A2：如果是交互式連接，則繼承全局變量interactive_timeout的值，如果是非交互式連接，則繼承全局變量wait_timeout的值。

驗證：

只修改全局變量interactive_timeout的值

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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)

開啓另外一個mysql客戶端，查看會話變量的值

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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)

發現，WAIT_TIMEOUT的值已經變爲10了。

但通過jdbc測試，wait_timeout的值依舊是28800

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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));

}

}

}

結果輸出如下：

INTERACTIVE_TIMEOUT: 10
WAIT_TIMEOUT: 28800

只修改全局變量wait_timeout的值

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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)

開啓另外一個mysql客戶端，查看會話變量的值

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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的值依舊是28800.

查看jdbc的結果

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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));

}

}

}

查看jdbc的結果

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INTERACTIVE_TIMEOUT: 28800

WAIT_TIMEOUT: 20

同時，新增了一段程序，等待20s後，再次執行查詢，報如下錯誤：

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

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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

總結

1. 控制連接最大空閒時長的wait_timeout參數。

2. 對於非交互式連接，類似於jdbc連接，wait_timeout的值繼承自服務器端全局變量wait_timeout。

對於交互式連接，類似於mysql客戶單連接，wait_timeout的值繼承自服務器端全局變量interactive_timeout。

3. 判斷一個連接的空閒時間，可通過show processlist輸出中Sleep狀態的時間

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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)

以上所述是小編給大家介紹的MySQL中interactive_timeout和wait_timeout的區別，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回覆大家的。在此也非常感謝大家對腳本之家網站的支持！

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