MySQL 实验室 因为专注，所以专业。

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  • MySQL 5.1 Reference Manual :: 12 SQL Statement Syntax :: 12.4 Database Administration Statements :: 12.4.6 Other Administrative Statements :: 12.4.6.4 KILL Syntax
    • MySQL 5.1 Reference Manual
    • Preface, Notes, Licenses
    • 1 General Information
    • 2 Installing and Upgrading MySQL
    • 3 Tutorial
    • 4 MySQL Programs
    • 5 MySQL Server Administration
    • 6 Backup and Recovery
    • 7 Optimization
    • 8 Language Structure
    • 9 Internationalization and Localization
    • 10 Data Types
    • 11 Functions and Operators
    • 12 SQL Statement Syntax
    • 13 Storage Engines
    • 14 High Availability and Scalability
    • 15 MySQL Enterprise Monitor
    • 16 Replication
    • 17 MySQL Cluster NDB 6.X/7.X
    • 18 Partitioning
    • 19 Stored Programs and Views
    • 20 INFORMATION_SCHEMA Tables
    • 21 Connectors and APIs
    • 22 Extending MySQL
    • A MySQL 5.1 Frequently Asked Questions
    • B Errors, Error Codes, and Common Problems
    • C MySQL Change History
    • D Restrictions and Limits
    • Index
    • Standard Index
    • C Function Index
    • Command Index
    • Function Index
    • INFORMATION_SCHEMA Index
    • Transaction Isolation Level Index
    • JOIN Types Index
    • Operator Index
    • Option Index
    • Privileges Index
    • SQL Modes Index
    • Status Variable Index
    • Statement/Syntax Index
    • System Variable Index

    12.4.6.4. KILL Syntax

    KILL [CONNECTION | QUERY] thread_id

    Each connection to mysqld runs in a separate thread. You can see which threads are running with the SHOW PROCESSLIST statement and kill a thread with the KILL thread_id statement.

    KILL allows the optional CONNECTION or QUERY modifier:

    • KILL CONNECTION is the same as KILL with no modifier: It terminates the connection associated with the given thread_id.

    • KILL QUERY terminates the statement that the connection is currently executing, but leaves the connection itself intact.

    If you have the PROCESS privilege, you can see all threads. If you have the SUPER privilege, you can kill all threads and statements. Otherwise, you can see and kill only your own threads and statements.

    You can also use the mysqladmin processlist and mysqladmin kill commands to examine and kill threads.

    Note

    You cannot use KILL with the Embedded MySQL Server library because the embedded server merely runs inside the threads of the host application. It does not create any connection threads of its own.

    When you use KILL, a thread-specific kill flag is set for the thread. In most cases, it might take some time for the thread to die because the kill flag is checked only at specific intervals:

    • In SELECT, ORDER BY and GROUP BY loops, the flag is checked after reading a block of rows. If the kill flag is set, the statement is aborted.

    • During ALTER TABLE, the kill flag is checked before each block of rows are read from the original table. If the kill flag was set, the statement is aborted and the temporary table is deleted.

    • During UPDATE or DELETE operations, the kill flag is checked after each block read and after each updated or deleted row. If the kill flag is set, the statement is aborted. Note that if you are not using transactions, the changes are not rolled back.

    • GET_LOCK() aborts and returns NULL.

    • An INSERT DELAYED thread quickly flushes (inserts) all rows it has in memory and then terminates.

    • If the thread is in the table lock handler (state: Locked), the table lock is quickly aborted.

    • If the thread is waiting for free disk space in a write call, the write is aborted with a “disk full” error message.

    • Warning

      Killing a REPAIR TABLE or OPTIMIZE TABLE operation on a MyISAM table results in a table that is corrupted and unusable. Any reads or writes to such a table fail until you optimize or repair it again (without interruption).