MySQL Bugs: #21428: "skipped 9 bytes from file: socket (3)" on "mysqladmin shutdown"

Bug #21428	"skipped 9 bytes from file: socket (3)" on "mysqladmin shutdown"
Submitted:	3 Aug 2006 11:50	Modified:	18 Dec 2006 18:49
Reporter:	Hartmut Holzgraefe	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Command-line Clients	Severity:	S3 (Non-critical)
Version:	5.0.22, 5.0.24, 5.0bk	OS:	Linux (linux)
Assigned to:	Michael Widenius	CPU Architecture:	Any

Description:
When doing a "mysqladmin shutdown" on a server >=5.0.22 
the server shuts down fine but the client reports

 $ mysqladmin shutdown
 skipped 9 bytes from file: socket (3)

This is independant of the client binary version so its
not a client but a server problem.

(I'm using debug builds, haven't tested whether this 
 happens with non-debug binaries, too)

How to repeat:
Shut down a >=5.0.22 server with 

  mysqladmin shutdown

Could be expected that the client discards some bytes before sending the command to the server.

Non-debug 5.0.25-BK does not demonstrate this behaviour:

openxs@suse:~/dbs/5.0> bin/mysqladmin -uroot shutdown
STOPPING server from pid file /home/openxs/dbs/5.0/var/suse.pid
060803 13:02:10  mysqld ended

[1]+  Done                    bin/mysqld_safe
openxs@suse:~/dbs/5.0> tail var/suse.err
060803 12:57:34 [Note] /home/openxs/dbs/5.0/libexec/mysqld: ready for connection
s.
Version: '5.0.25'  socket: '/tmp/mysql.sock'  port: 3306  Source distribution
060803 13:02:07 [Note] /home/openxs/dbs/5.0/libexec/mysqld: Normal shutdown

060803 13:02:07  InnoDB: Starting shutdown...
060803 13:02:10  InnoDB: Shutdown completed; log sequence number 0 1686575588
060803 13:02:10 [Note] /home/openxs/dbs/5.0/libexec/mysqld: Shutdown complete

060803 13:02:10  mysqld ended

5.1.12-beta-debug does not demonstrate this behaviour also.

5.1.12-beta-debug does not demonstrate this behaviour also.

I was not able to repeat the behaviour described with 5.0.25-debug as well:

openxs@suse:~/dbs/5.0> bin/mysqld_safe --socket=/tmp/mysql5.sock &
[1] 12203
openxs@suse:~/dbs/5.0> Starting mysqld daemon with databases from /home/openxs/d
bs/5.0/var

openxs@suse:~/dbs/5.0> bin/mysql -uroot --socket=/tmp/mysql5.sock
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1 to server version: 5.0.25-debug

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql> exit
Bye
openxs@suse:~/dbs/5.0> bin/mysqladmin -uroot --socket=/tmp/mysql5.sock shutdown
STOPPING server from pid file /home/openxs/dbs/5.0/var/suse.pid
060803 13:32:51  mysqld ended

[1]+  Done                    bin/mysqld_safe --socket=/tmp/mysql5.sock

What am I doing wrong?

No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

You need to build with -DEXTRA_DEBUG to see it.
It's caused by double send_eof(thd); in 
dispatch_command(), case COM_SHUTDOWN. The second eof packet is those "9 bytes" that are ignored.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/16181

ChangeSet@1.2380, 2006-11-30 03:40:42+02:00, monty@mysql.com +63 -0
  Fixed compiler warnings (Mostly VC++):
  - Removed not used variables
  - Changed some ulong parameters/variables to ulonglong (possible serious bug)
  - Added casts to get rid of safe assignment from longlong to long (and similar)
  - Added casts to function parameters
  - Fixed signed/unsigned compares
  - Added some constructores to structures
  - Removed some not portable constructs
  
  Better fix for bug Bug #21428 "skipped 9 bytes from file: socket (3)" on "mysqladmin shutdown"
  (Added new parameter to net_clear() to define when we want the communication buffer to be emptied)

Fix will be in 5.1.14

This will not be fixed in 5.0, as it only affects DBUG builds (and are thus not critical)

Noted in 5.1.14 changelog.

For debug builds, mysqladmin shutdown displayed an extraneous "skipped
9 bytes from file: socket (3)" message.