MySQL Bugs: #41843: Can not do backup to a named pipe on windows

Bug #41843	Can not do backup to a named pipe on windows
Submitted:	3 Jan 2009 19:36	Modified:	25 Feb 2010 0:30
Reporter:	Tomas Dalebjörk	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Backup	Severity:	S3 (Non-critical)
Version:	6.0.8	OS:	Windows
Assigned to:	Chuck Bell	CPU Architecture:	Any
Tags:	Backup, MySQL, namedpipe

Description:
I am trying to backup to a named pipe on windows, but I got the following error..

 mysql@test:dbwriter:command:mysql --user=root --database=test < "C:\Program Files\repostor\Data Protector for MySQL\tmp\test"
ERROR 1632 (HY000) at line 1: Can't write to backup location '\\.\pipe\test' (file already exists?)
  mysql@ktest:dbwriter:end rc=1

This works perfectly when I done this with the "mysqldump > \\.\pipe\test" command, so there is nothing wrong with the named-pipe.

maybee you can apply the similare fix for Windows as for the bug below on UNIX...

Bug #37012  	Online backup: Can't backup to a pipe.

Regards Tomas

How to repeat:
1) Create a NamedPipe in windows.
2) logon to MySQL
3) execute : "backup database test to '\\\\.\\pipe\\test';

Suggested fix:
do not care if a file exist, overwrite the file, or add and argument to the backup command in mysql.

The support of Windows named pipes is broken, see bug: http://bugs.mysql.com/bug.php?id=41860.

I dont understand?
The command below mentioned in the bug, shows:

mysql> show variables like "%pipe%";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| named_pipe    | OFF   |
+---------------+-------+
1 row in set (0.03 sec)

mysql>

What you are saying is that NamedPipes are not supported in MySQL on windows platform?
How about backup the database to standard output.?

Verified as described.

can you please explain.
Is it possinle to do backup on windows to named pipe?
or not?
if so; are there any parameter I need to set to get this to work?

May be related to BUG#40975.

Confirmed that the problem has not been fixed. Backup cannot send data to a Windows named pipe server.

There appears to be a problem in how the backup path resolution handles the Windows pipe name. It is changing '\\.\pipe\namedpipe' to '\\pipe\namedpipe' which is a file path, not a named pipe in Windows.

Confirmed. The problem is in the safe_cleanup_cat_path() method.

For debugging or development testing, one can use the named pipe server code depicted here:

http://msdn.microsoft.com/en-us/library/aa365601%28VS.85%29.aspx

Okey,
Are you planning to fix this problem?
repostors desing is based on namedpipes.

regards Tomas

Yes, an 'in progress' status indicates it will be fixed. ;)

Also, there is a workaround. For piping to named pipes on the local host -- which \\.\pipe\namedpipe indicates, one can use: \\localhost\pipe\namedpipe and the backup code will work correctly. For example:

BACKUP DATABASE x TO '\\\\localhost\\pipe\\namedpipe';

Thus, the fix for this bug will be such that \\.\pipe is recognized as a named pipe (iff on windows) and the period is not removed.

Note: While the fix for the bug is easy, creating a genuine test will be a bit more difficult. One possibility is to write a console application that can consume or produce a backup image file. For example:

winpipebackup [--SEND 'backup_image_file' | --RECEIVE 'backup_image_file']

A tool like this would allow test cases like:

- backup to named pipe and restore result using file-based restore
- restore from named pipe 

...

No test cases for MTR tests shall be created with this patch. WL#5107 is designed to permit testing of using named pipes on Windows.

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/85793

2874 Chuck Bell	2009-10-05
      BUG#41843 : Can not do backup to a named pipe on windows
      
      The system currently interprets '\\.\pipe\namedpipe' as a fixed
      path translated to 'pipe\namedpipe' which is not a valid
      named pipe on windows. The path in question is a valid 
      representation of '\\localhost\pipe\namedpipe' and therefore
      should be preserved.
      
      This patch preserves the path notation.
     @ mysys/mf_pack.c
        Preserve the \\.\ at the start of the path.
     @ unittest/mysys/safe_cleanup_cat_path-t.c
        Added unit test cases for paths that form a named pipe including
        a test for the specific failure described in the bug report.

Approved, pending changes.

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/86995

2874 Chuck Bell	2009-10-15
      BUG#41843 : Can not do backup to a named pipe on windows
      
      The system currently interprets '\\.\pipe\namedpipe' as a fixed
      path translated to 'pipe\namedpipe' which is not a valid
      named pipe on windows. The path in question is a valid 
      representation of '\\localhost\pipe\namedpipe' and therefore
      should be preserved.
      
      This patch preserves the path notation.
     @ mysys/mf_pack.c
        Preserve the \\.\ sequence in the path.
     @ unittest/mysys/safe_cleanup_cat_path-t.c
        Added unit test cases for paths that form a named pipe including
        a test for the specific failure described in the bug report.

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/87006

2881 Chuck Bell	2009-10-15
      BUG#41843 : Can not do backup to a named pipe on windows
      
      The system currently interprets '\\.\pipe\namedpipe' as a fixed
      path translated to 'pipe\namedpipe' which is not a valid
      named pipe on windows. The path in question is a valid 
      representation of '\\localhost\pipe\namedpipe' and therefore
      should be preserved.
      
      This patch preserves the path notation.
     @ mysys/mf_pack.c
        Preserve the \\.\ sequence in the path.
     @ unittest/mysys/safe_cleanup_cat_path-t.c
        Added unit test cases for paths that form a named pipe including
        a test for the specific failure described in the bug report.

Pushed into 6.0.14-alpha (revid:ingo.struewing@sun.com-20100218152520-s4v1ld76bif06eqn) (version source revid:ingo.struewing@sun.com-20100119103538-wtp5alpz4p2jayl5) (merge vers: 6.0.14-alpha) (pib:16)

Noted in 6.0.14 changelog.

On Windows, BACKUP DATABASE to a named pipe did not work.