Bug #4732 Slave's relay log still created when log-bin is turned OFF
Submitted: 23 Jul 2004 21:24 Modified: 23 Jul 2004 21:39
Reporter: Joe Read Email Updates:
Status: Not a Bug Impact on me:
Category:MySQL Server Severity:S3 (Non-critical)
Version:4.0.20 OS:FreeBSD (freebsd-release 5.2.1)
Assigned to: CPU Architecture:Any

[23 Jul 2004 21:24] Joe Read
When I set up a slave server running 4.0.20, set up the /etc/my.cnf file with the master's settings, comment out log-bin then start up the server it still creates relay logs.

When I do "SHOW VARIABLES", the value for log_bin is off, log_update is off and log_slave_updates is off.

Maybe I'm on the wrong track here, maybe log-bin doesn't control the relay log on the slave.  If that's the case, then this is still a documentation issue as I can't find any clear way of disabling it.  However, you should be able to disable this feature since not everybody is going to use A -> B -> C replication, as in my case where I just want A -> B where B is a simple backup slave and doesn't get any client connections (slaves or otherwise).

How to repeat:
Install source distribution (configure --prefix=/usr/local --with-mysqld-user=nobody && make install), copy /usr/local/share/mysql/my_huge.cnf to /etc/my.cnf and customize master settings (server-id = 2), comment out log-bin (in BOTH places in the log!) and start server.  Relay logs will be created with no apparent means of disabling them.

Here is my my.cnf file:

password        = **********
user                    = root
host                    = sql.masterhost.com
port                    = 3306
socket          = /tmp/mysql.sock

# Here follows entries for some specific programs

# The MySQL server
port            = 3306
socket          = /tmp/mysql.sock

key_buffer = 384M
max_allowed_packet = 1M
table_cache = 512
sort_buffer_size = 2M
read_buffer_size = 2M
myisam_sort_buffer_size = 64M
thread_cache = 8
query_cache_size = 32M
# Try number of CPU's*2 for thread_concurrency
thread_concurrency = 4

# Don't listen on a TCP/IP port at all. This can be a security enhancement,
# if all processes that need to connect to mysqld run on the same host.
# All interaction with mysqld must be made via Unix sockets or named pipes.
# Note that using this option without enabling named pipes on Windows
# (via the "enable-named-pipe" option) will render mysqld useless!

# Replication Master Server (default)
# binary logging is required for replication

# required unique id between 1 and 2^32 - 1
# defaults to 1 if master-host is not set
# but will not function as a master if omitted
#server-id      = 1

# Replication Slave (comment out master section to use this)
# To configure this host as a replication slave, you can choose between
# two methods :
# 1) Use the CHANGE MASTER TO command (fully described in our manual) -
#    the syntax is:
#    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;
#    where you replace <host>, <user>, <password> by quoted strings and
#    <port> by the master's port number (3306 by default).
#    Example:
#    MASTER_USER='joe', MASTER_PASSWORD='secret';
# OR
# 2) Set the variables below. However, in case you choose this method, then
#    start replication for the first time (even unsuccessfully, for example
#    if you mistyped the password in master-password and the slave fails to
#    connect), the slave will create a master.info file, and any later
#    change in this file to the variables' values below will be ignored and
#    overridden by the content of the master.info file, unless you shutdown
#    the slave server, delete master.info and restart the slaver server.
#    For that reason, you may want to leave the lines below untouched
#    (commented) and instead use CHANGE MASTER TO (see above)
# required unique id between 2 and 2^32 - 1
# (and different from the master)
# defaults to 2 if master-host is set
# but will not function as a slave if omitted
server-id       = 2
# The replication master for this slave - required
master-host     = sql.masterhost.com
# The username the slave will use for authentication when connecting
# to the master - required
master-user     = root
# The password the slave will authenticate with when connecting to
# the master - required
master-password = **********
# The port the master is listening on.
# optional - defaults to 3306
#master-port     =  <port>
# binary logging - not required for slaves, but recommended

# Point the following paths to different dedicated disks
#tmpdir         = /tmp/
#log-update     = /path-to-dedicated-directory/hostname

# Uncomment the following if you are using BDB tables
#bdb_cache_size = 384M
#bdb_max_lock = 100000

# Uncomment the following if you are using InnoDB tables
#innodb_data_home_dir = /usr/local/var/
#innodb_data_file_path = ibdata1:2000M;ibdata2:10M:autoextend
#innodb_log_group_home_dir = /usr/local/var/
#innodb_log_arch_dir = /usr/local/var/
# You can set .._buffer_pool_size up to 50 - 80 %
# of RAM but beware of setting memory usage too high
#innodb_buffer_pool_size = 384M
#innodb_additional_mem_pool_size = 20M
# Set .._log_file_size to 25 % of buffer pool size
#innodb_log_file_size = 100M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

max_allowed_packet = 16M

# Remove the next comment character if you are not familiar with SQL

key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M

key_buffer = 256M
sort_buffer_size = 256M
read_buffer = 2M
write_buffer = 2M


Suggested fix:
Add a relay-log-bin option in the configuration and/or update documentation?
[23 Jul 2004 21:39] Paul Dubois
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.mysql.com/documentation/ and the instructions on
how to report a bug at http://bugs.mysql.com/how-to-report.php

Additional info:

If a server is a replication slave, it *must* use the relay
logs. The relay logs are used for communication between
the slave's I/O and SQL threads.