MySQL Bugs: #38197: Errors in @@init_slave not visible in 'show slave status'

Bug #38197	Errors in @@init_slave not visible in 'show slave status'
Submitted:	17 Jul 2008 14:09	Modified:	6 May 2009 14:40
Reporter:	Sven Sandberg	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Replication	Severity:	S3 (Non-critical)
Version:	5.1+, 5.1.28-bzr	OS:	Any
Assigned to:	Alfranio Junior	CPU Architecture:	Any
Tags:	error reporting, init_slave, replication, rli->report, show slave status, Slave_SQL_Error, sql_print_error

Description:
Some errors that cause the slave SQL thread to stop are not shown in the Slave_SQL_Error column of "SHOW SLAVE STATUS". Instead, the error is only in the server's error log.

That makes it difficult to analyze the error for the user. In particular, when errors happen in pushbuild, the server logs are often removed, whereas a slave that gets an unexpected error usually issues "SHOW SLAVE STATUS" so that the error is part of the output from the test.

One example of an error that stops the slave but is not shown by "SHOW SLAVE STATUS" is when @@global.init_slave is set incorrectly (e.g., it contains something that is not valid SQL).

How to repeat:
Either inspect the code or run this test case:

--------- BEGIN TEST CASE ---------
source include/master-slave.inc;

connection slave;

STOP SLAVE;
source include/wait_for_slave_to_stop.inc;
# produce an error
SET @@global.init_slave = 'garbage';
START SLAVE;
source include/wait_for_slave_sql_to_stop.inc;

query_vertical SHOW SLAVE STATUS;

--------- END TEST CASE ---------

Suggested fix:
Replace calls to sql_print_error() by calls to rli->report() in slave.cc:handle_slave_sql()

Thank you for a bug report. Verified just as described with latest 5.1.28 from bzr on Linux.

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/65337

2768 Alfranio Correia	2009-02-05
      BUG#38197 Errors in @@init_slave not visible in 'show slave status'
      
      Some errors that cause the slave SQL thread to stop are not shown in the Slave_SQL_Error
      column of "SHOW SLAVE STATUS". Instead, the error is only in the server's error log.
      
      That makes it difficult to analyze the error for the user. One example of an error that stops the slave
      but is not shown by "SHOW SLAVE STATUS" is when @@global.init_slave is set incorrectly
      (e.g., it contains something that is not valid SQL).
      
      Three failures were not correctly reported:
      
      1 - Failures during slave thread initialization
      2 - Failures while initializing the relay log position right after
      starting the slave thread.
      3 - Failures while processing queries passed through the init_slave
      option.
      
      This patch fixes the issues by reporting the errors through relay-info->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/65888

2768 Alfranio Correia	2009-02-11
      BUG#38197 Errors in @@init_slave not visible in 'show slave status'
            
      Some errors that cause the slave SQL thread to stop are not shown in the
      Slave_SQL_Error column of "SHOW SLAVE STATUS". Instead, the error is only 
      in the server's error log.
            
      That makes it difficult to analyze the error for the user. One example of an error
      that stops the slave but is not shown by "SHOW SLAVE STATUS" is when @@global.init_slave
      is set incorrectly (e.g., it contains something that is not valid SQL).
            
      Three failures were not correctly reported:
            
      1 - Failures during slave thread initialization
      2 - Failures while initializing the relay log position right after
      starting the slave thread.
      3 - Failures while processing queries passed through the init_slave
      option.
            
      This patch fixes the issues by reporting the errors through relay-info->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/68946

2832 Alfranio Correia	2009-03-11 [merge]
      auto-merge BUG#38197 Errors in @@init_slave not visible in 'show slave status'

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/68975

3112 Alfranio Correia	2009-03-12 [merge]
      merge 5.1-bugteam --> 6.0-bugteam BUG#38197 Errors in @@init_slave not visible in 'show slave status'

Pushed into 5.1.35 (revid:davi.arnaut@sun.com-20090505190206-9xmh7dlc6kom8exp) (version source revid:davi.arnaut@sun.com-20090505190206-9xmh7dlc6kom8exp) (merge vers: 5.1.35) (pib:6)

Documented in the 5.1.35 changelog as follows:

        The following erors were not correctly reported:

              Failures during slave thread initialization

              Failures while initializing the relay log position
              right after starting the slave thread.

              Failures while processing queries passed through the
              init_slave option.

        Information about these types of failures can now be found in the 
        output of SHOW SLAVE STATUS.

Status -> NDI : waiting for merge to 6.0.

Pushed into 6.0.12-alpha (revid:svoj@sun.com-20090506125450-yokcmvqf2g7jhujq) (version source revid:alfranio.correia@sun.com-20090406031810-k14c2nwvf8rikm3a) (merge vers: 6.0.11-alpha) (pib:6)

Bugfix also noted in the 6.0.12 changelog. Closed.

Pushed into 5.1.35-ndb-6.3.26 (revid:jonas@mysql.com-20090615074202-0r5r2jmi83tww6sf) (version source revid:jonas@mysql.com-20090615070837-9pccutgc7repvb4d) (merge vers: 5.1.35-ndb-6.3.26) (pib:6)

Pushed into 5.1.35-ndb-7.0.7 (revid:jonas@mysql.com-20090615074335-9hcltksp5cu5fucn) (version source revid:jonas@mysql.com-20090615072714-rmfkvrbbipd9r32c) (merge vers: 5.1.35-ndb-7.0.7) (pib:6)

Pushed into 5.1.35-ndb-6.2.19 (revid:jonas@mysql.com-20090615061520-sq7ds4yw299ggugm) (version source revid:jonas@mysql.com-20090615054654-ebgpz7elwu1xj36j) (merge vers: 5.1.35-ndb-6.2.19) (pib:6)