MySQL Bugs: #19614: log_bin variables show something else than entered in my.cnf

Bug #19614	log_bin variables show something else than entered in my.cnf
Submitted:	8 May 2006 14:56	Modified:	19 Aug 2010 22:28
Reporter:	Oli Sennhauser	Email Updates:
Status:	Verified	Impact on me:	None
Category:	MySQL Server: General	Severity:	S4 (Feature request)
Version:	5.0, 5.1	OS:	Any
Assigned to:	Assigned Account	CPU Architecture:	Any
Tags:	Contribution

Description:
log-bin in my.cnf is entered like this:

log-bin               = /backup/binary_log

But shown in show variables like this:

show variables like 'log%';
+---------------------------------+-------+
| Variable_name                   | Value |
+---------------------------------+-------+
| log_bin                         | ON    |
+---------------------------------+-------+

Completly inconsistent.

How to repeat:
Dito.

Suggested fix:
Split binary logging into 2 different variables:
1.) log_bin_path [DEFAULT | ...]
2.) log_bin [ON|OFF]

See also Bug 19612

Workaround:

shell> mysqld --help --verbose | grep "^log-bin "

Patch against current 5.1 bazaar tree

Attachment: bug19614.patch (text/x-diff), 2.19 KiB.

Patch attached to this bug adds the 'log_bin_name' global variable, shows the same output as the workaround.

Please make explicit in this bug report:

1. Whether this is a bug. The system variable gives info about whether 
   logging is on or not, not about the file name.  Isn't that 
   what one can expect?

2. What would be the benefit of splitting the variable into two?
   Why would anyone want it?

Setting bug to open until this is added.

I need to consume binlogs with an external process.  I need to know where the log files are stored in order to read them, assuming I have proper filesystem permissions to do so.

Either 'SHOW BINARY LOGS' should include the path name
OR
SHOW GLOBAL STATUS LIKE 'log_bin' should show the path name
OR
There should be a new global status variable called 'log_bin_path'

I've just hit the same bug.

I want to clean up/purge binlog files by compare "show master logs" with a glob of the binlog dir. I'd like to be able to get binlog dir and the binlog file root name programmatically.

This works for the relay logs:

+-----------------------+---------------------------------+
| Variable_name         | Value                           |
+-----------------------+---------------------------------+
| max_relay_log_size    | 0                               | 
| relay_log             | relay_bin/mysql-relay-bin       | 
| relay_log_index       | relay_bin/mysql-relay-bin.index | 
| relay_log_info_file   | relay-log.info                  | 
| relay_log_purge       | ON                              | 
| relay_log_space_limit | 0                               | 
+-----------------------+---------------------------------+

So, I know that the relay log files are:

@@datadir/relay_bin/mysql-relay-bin.??????

But, I can't do the same thing for the binlog files.

I have the same problem.  Someone asked why this is needed.  It is needed because I want my application to monitor free space in the area and alert when space may be a problem.  Other file locations are available via the database engine.  This one is not.

I would like get the location from these logs using a system variable so that from a shell script I can copy them. Sound like still is not working :-(

I would like get the location from these logs using a system variable so that from a shell script I can copy them. Sound like still is not working in 5.1 :-(

This is being implemented in WL#5465 right now, so look there for more information.

That worklog doesn't specify variables that list the directory in which the files are stored. Those values will be useful for scripting and I prefer not to have all scripts extract the dirname from '/path/to/binlogs/bl-'

patch to add binlog_file_basedir and binlog_index_basedir global variables

Attachment: 0001-Add-global-variables-to-list-directory-for-binlog-fi.patch (, text), 5.67 KiB.