Very Computer

> I'm running 4.1.13 on Linux as master, with 4.1.12 on XP as slave (in
> house test setup).

> This vaguely duplicates what is set up on the live servers, except that
> the slave is 4.1.3 on NT4.

> On the test setup, if the logs are flushed on the master, the bin log is
> rotated to the next number, after closing (and preserving) the old one. On
> the slave, the change to the master bin-log is duly recognised in the
> slave status output.

> If I issue 'flush logs' on the slave, however, the old
> [servername]-relay-bin.0000nn file is closed, the n+1 is opened, and the
> original is deleted completely.

> My only reason for wishing to rotate logs this way is to prevent files
> getting too large to handle effectively in the event of needing to
> reinstate (either the master or the slave). However, the way that log
> flush on the slave seems to work implies that a backup of it should be
> taken before flushing, or you won't ever see that logged data again.

> Is this the way it is meant to be? I don't want to institute any log
> rotation policy on the slave of the live setup if this happens.....

> Regards
> Terry Riley

----- Original Message -----

> > I'm running 4.1.13 on Linux as master, with 4.1.12 on XP as slave (in
> > house test setup).

> > This vaguely duplicates what is set up on the live servers, except
> > that the slave is 4.1.3 on NT4.

> > On the test setup, if the logs are flushed on the master, the bin log
> > is rotated to the next number, after closing (and preserving) the old
> > one. On the slave, the change to the master bin-log is duly
> > recognised in the slave status output.

> > If I issue 'flush logs' on the slave, however, the old
> > [servername]-relay-bin.0000nn file is closed, the n+1 is opened, and
> > the original is deleted completely.

> > My only reason for wishing to rotate logs this way is to prevent
> > files getting too large to handle effectively in the event of needing
> > to reinstate (either the master or the slave). However, the way that
> > log flush on the slave seems to work implies that a backup of it
> > should be taken before flushing, or you won't ever see that logged
> > data again.

> > Is this the way it is meant to be? I don't want to institute any log
> > rotation policy on the slave of the live setup if this happens.....

> > Regards
> > Terry Riley

> see http://dev.mysql.com/doc/mysql/en/slave-logs.html

> Basically, the master's binary log and the slave's relay log, though
> the same format, serve different purposes. The slave's relay log is a
> short-term copy of as much of the master's binary log as the slave's IO
> thread has read; this relay log is what the slave's SQL thread
> processes. This file is not needed once it is read since it does not
> store anything that is not stored in the master's binary log, and this
> file is not used for replication from the slave to another server.

> If your slave is handling updates, it should be writing a binary log so
> you can replicate those updates back to the master.

> Best regards,
> Devananda vdv

> ----- Original Message -----

>>>I'm running 4.1.13 on Linux as master, with 4.1.12 on XP as slave (in
>>>house test setup).

>>>This vaguely duplicates what is set up on the live servers, except
>>>that the slave is 4.1.3 on NT4.

>>>On the test setup, if the logs are flushed on the master, the bin log
>>>is rotated to the next number, after closing (and preserving) the old
>>>one. On the slave, the change to the master bin-log is duly
>>>recognised in the slave status output.

>>>If I issue 'flush logs' on the slave, however, the old
>>>[servername]-relay-bin.0000nn file is closed, the n+1 is opened, and
>>>the original is deleted completely.

>>>My only reason for wishing to rotate logs this way is to prevent
>>>files getting too large to handle effectively in the event of needing
>>>to reinstate (either the master or the slave). However, the way that
>>>log flush on the slave seems to work implies that a backup of it
>>>should be taken before flushing, or you won't ever see that logged
>>>data again.

>>>Is this the way it is meant to be? I don't want to institute any log
>>>rotation policy on the slave of the live setup if this happens.....

>>>Regards
>>>Terry Riley

>>see http://dev.mysql.com/doc/mysql/en/slave-logs.html

>>Basically, the master's binary log and the slave's relay log, though
>>the same format, serve different purposes. The slave's relay log is a
>>short-term copy of as much of the master's binary log as the slave's IO
>>thread has read; this relay log is what the slave's SQL thread
>>processes. This file is not needed once it is read since it does not
>>store anything that is not stored in the master's binary log, and this
>>file is not used for replication from the slave to another server.

>>If your slave is handling updates, it should be writing a binary log so
>>you can replicate those updates back to the master.

>>Best regards,
>>Devananda vdv

> Thanks, Devananda!

> I really should have looked at the manual once again.

> I'm not sure what you meant by the last sentence - all the updates are
> done on the master, and they are naturally replicated to the slave. Did
> you mean 'handling DIRECT updates'? I turned on the binlog for the slave,
> then made some updates on the master, and nothing changed in the slave bin
> log, only the relay log. That is normal, yes?

> Cheers
> Terry