inconsistent mysqladmin return value, debian init-script dependency

[Tobias Brox]

One (or two) minor bug(s) that I arbritrary hit on because someone had overwritten /etc/mysql/debian.cnf ...

This doesn't quite make sense:

$ mysqladmin -u foo -pbar ping
mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'foo'@'localhost' (using password: YES)'
$ echo $?
0

At the other hand:

$ mysqladmin --defaults-file=/foo/bar
Could not open required defaults file: /foo/bar
Fatal error in defaults handling. Program aborted
$ echo $?
1

The init-script is checking weather mysql is running or not by doing ...

  mysqladmin --defaults-file=/etc/mysql/debian.cnf ping

This means mysql is always regarded as running if the password in /etc/mysql/debian.cnf is wrong, but always regarded as being down if the password in /etc/mysql/debian.cnf

$ cat /etc/issue
Ubuntu 14.04.1 LTS \n \l

root@glimmer:~# aptitude show percona-server-server-5.5
Package: percona-server-server-5.5
(...)
Version: 5.5.39-rel36.0-697.trusty

[Muhammad Irfan (muhammad-irfan)]

I am able to verify with latest Percona Server 5.5 version.

root@testnode:/etc/mysql# lsb_release -a
Distributor ID: Ubuntu
Description: Ubuntu 14.04.1 LTS
Release: 14.04
Codename: trusty

mysql> show global variables like '%version%';
+-------------------------+--------------------------------------------------+
| Variable_name | Value |
+-------------------------+--------------------------------------------------+
| innodb_version | 5.5.40-36.1 |
| protocol_version | 10 |
| slave_type_conversions | |
| version | 5.5.40-36.1 |
| version_comment | Percona Server (GPL), Release 36.1, Revision 707 |
| version_compile_machine | x86_64 |
| version_compile_os | debian-linux-gnu |
+-------------------------+--------------------------------------------------+

root@testnode:~# mysqladmin --user=root --password=xxxx ping
mysqld is alive
 root@testnode:~# echo $?
0

Exit status is zero which is correct, but below when i used the wrong credentials exit status is still zero instead of non-zero.

root@testnode:~# mysqladmin --user=foo --password=bar ping
mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'foo'@'localhost' (using password: YES)'
 root@testnode:~# echo $?
0

[Alexey Kopytov (akopytov)]

I don't understand what exactly is the problem in this report. "mysqladmin ping" works by description:

"Check whether the server is available. The return status from mysqladmin is 0 if the server is running, 1 if it is not. This is 0 even in case of an error such as Access denied, because this means that the server is running but refused the connection, which is different from the server not running. "

http://dev.mysql.com/doc/refman/5.6/en/mysqladmin.html

There may be a problem in the init script, but I don't see it. If there's a wrong password in the configuration file, but the server itself is up, it will report no errors, because the server is running. If the specified configuration file is missing, it will report an error. Which looks correct to me.

[Valerii Kravchuk (valerii-kravchuk)]

Tobias,

This part is OK (not a bug), mysqladmin works as documented: "This means mysql is always regarded as running if the password in /etc/mysql/debian.cnf is wrong". It's so because if server says "access denied" it means there is a running server to say so.

As for this part: "but always regarded as being down if the password in /etc/mysql/debian.cnf", it seems your sentence is not complete. Do you mean there is problem if /etc/mysql/debian.cnf just does not exist or is nor readable by the user that runs MySQL server? Please, clarify.

[Tobias Brox (c-tobias)]

> As for this part: "but always regarded as being down if the password in
> /etc/mysql/debian.cnf", it seems your sentence is not complete. Do you
> mean there is problem if /etc/mysql/debian.cnf just does not exist or is
> nor readable by the user that runs MySQL server? Please, clarify.

Correct, sorry for that.

--
Tobias Brox
Senior System Consultant
Redpill Linpro AS - Changing the game
Mobil: [phone]
Kontor: [phone]

[Launchpad Janitor (janitor)]

[Expired for Percona Server 5.7 because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for Percona Server 5.5 because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

[Expired for Percona Server 5.6 because there has been no activity for 60 days.]

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-3186