Rick,
I think that you are proposing to do planned failover by sending a
command or set of commands through the replication stream. That is a
great idea. Some failovers are more complicated depending on whether
slaves use different grants than masters but all of that should be
possible with this approach. And for those of us with many slaves
replicating from a master, this could make the process much less
painful (time consuming and error prone) than it is today.
On Thu, May 15, 2008 at 1:44 PM, Rick James <rjames@stripped> wrote:
>
> And it would probably work for dual-master, there things get tricky with queries
> crossing 'in the network'.
>
> And figuring out if "all's quite" become much easier.
>
> The script would take seconds; the manual equivalent would be painful, slow, and more
> error prone. You would have to figure out a different offset for each slave. And
> [perhaps] dual master setups would be impossible because of different binlog ordering on
> different slaves. [Assuming the evil of both masters accepting writes.)
>
>
>
> > -----Original Message-----
> > From: Rick James
> > Sent: Thursday, May 15, 2008 1:40 PM
> > To: 'Eric Bergen'
> > Cc: Internals List
> > Subject: RE: Adding new flush commands
> >
> > I pondered the flush & stop a year ago; let me see if I can
> > justify it...
> >
> > Let's say you need to move all (or some) of your slaves from
> > one master (or relay) to another. And you want to do it with
> > minimal downtime. If I can get all the slaves to stop at
> > exactly the same point (without stopping the master), then I
> > can have a script do the CHANGE MASTER on each one (to the same value)
> >
> > Meanwhile (if necessary), the script could do SLAVE START on
> > the other slaves.
> >
> >
> > MySQL Geeks - Consulting & Review
> >
> >
> >
> > > -----Original Message-----
> > > From: eric.bergen@stripped
> > > [mailto:eric.bergen@stripped] On Behalf Of Eric Bergen
> > > Sent: Thursday, May 15, 2008 1:31 PM
> > > To: Rick James
> > > Cc: Internals List
> > > Subject: Re: Adding new flush commands
> > >
> > > I think it should rotate after N bytes like the binlog. It
> > can also be
> > > rotated with it's own flush slow log; command. I don't know
> > how useful
> > > a flush binary log and slave stop sql will be since it will stop all
> > > slaves.
> > >
> > > On Thu, May 15, 2008 at 10:47 AM, Rick James
> > > <rjames@stripped> wrote:
> > > > :)
> > > >
> > > > I would like the slowlogs rotated; numbered is fine.
> > > >
> > > > When to rotate slowlog?
> > > > * After N bytes (a la binlog) ?
> > > > * On demand -- In this case, would not like it tied to
> > > other logs: I might want to rotate the slowlogs daily, but
> > > never explicitly rotate any other logs.
> > > > * On restart ? Once there is rotation, this seems ok. (No
> > > strong opinion.)
> > > >
> > > > General log
> > > > * would like to turn on/off without restarting server
> > > > * "rotation" with numbered files would be nice
> > > > * Again, would not like it to be tied to any other flush.
> > > >
> > > > FLUSH LOGS -- command to flush all -- ok
> > > > FLUSH [SLOW|GENERAL|BIN|...] LOG -- flush one log.
> > > >
> > > > Also, I would like FLUSH BIN LOG to be optionally
> > > replicated! This would lead to some interesting tricks for
> > > taking snapshots and/or pointing a slave to a different
> > > master. Think about it; this would easily give you a precise
> > > position. [I think]
> > > >
> > > > Maybe this combo as an atomic operation
> > > > FLUSH BINLOG AND SLAVE STOP SQL;
> > > > would be 'necessary' for the idea I presented above.
> > > >
> > > >
> > > > MySQL Geeks - Consulting & Review
> > > > Email: rjames@stripped
> > > > Messenger : rjasdf
> > > > http://twiki.corp.yahoo.com/view/Devel/MySQLGeeks
> > > >
> > > >
> > > >
> > > >> -----Original Message-----
> > > >> From: eric.bergen@stripped
> > > >> [mailto:eric.bergen@stripped] On Behalf Of Eric Bergen
> > > >> Sent: Thursday, May 15, 2008 10:32 AM
> > > >> To: Rick James
> > > >> Cc: Internals List
> > > >> Subject: Re: Adding new flush commands
> > > >>
> > > >> Rick,
> > > >>
> > > >> Flush slow logs (soon to be log or logs) is in the patch
> > > below. There
> > > >> is a problem in that the slow query log can be flushed but
> > > there isn't
> > > >> any code to rotate it. A flush reopens the file with a new
> > > header. In
> > > >> a separate patch I'm going to update the slow, general,
> > > and error logs
> > > >> so they rotate in numbered files like the binary logs.
> > What do you
> > > >> think?
> > > >>
> > > >> -Eric
> > > >>
> > > >> On Tue, May 13, 2008 at 10:15 AM, Rick James
> > > >> <rjames@stripped> wrote:
> > > >> > FLUSH SLOW LOG; please
> > > >> >
> > > >> >
> > > >> > MySQL Geeks - Consulting & Review
> > > >> > Email: rjames@stripped
> > > >> > Messenger : rjasdf
> > > >> > http://twiki.corp.yahoo.com/view/Devel/MySQLGeeks
> > > >> >
> > > >> >
> > > >> >
> > > >> >> -----Original Message-----
> > > >> >> From: Sergei Golubchik [mailto:serg@stripped]
> > > >> >> Sent: Tuesday, May 13, 2008 12:16 AM
> > > >> >> To: Eric Bergen
> > > >> >> Cc: Internals List
> > > >> >> Subject: Re: Adding new flush commands
> > > >> >>
> > > >> >> Hi!
> > > >> >>
> > > >> >> On May 12, Eric Bergen wrote:
> > > >> >> > Hi,
> > > >> >> >
> > > >> >> > I'm trying to split the flush logs command into
> > > several different
> > > >> >> > flush commands. Examples are;
> > > >> >> > flush binary log;
> > > >> >> > flush relay log;
> > > >> >> >
> > > >> >> > My problem is that when I add the log symbol the
> new
> > > >> >> commands work but
> > > >> >> > the log function is disabled with a parse error:
> > > >> >> >
> > > >> >> > mysqltest: At line 495: query 'select log()' failed
> with
> > > >> wrong errno
> > > >> >> > 1064: 'You have an error in your SQL syntax; check
> the
> > > >> manual that
> > > >> >> > corresponds to your MySQL server version for the
> right
> > > >> syntax to use
> > > >> >> > near '()' at line 1', instead of 1582...
> > > >> >> >
> > > >> >> > If I change the commands to flush binary logs (as in
> the
> > > >> >> patch below)
> > > >> >> > it works great.
> > > >> >> >
> > > >> >> > Is there something special I have to define to
> prevent
> > > >> my log symbol
> > > >> >> > from conflicting with the log function?
> > > >> >>
> > > >> >> Yes :(
> > > >> >> You need to remove LOG function from item_create.cc and
> add
> > > >> >> an explicit
> > > >> >> rule for it in sql_yacc.yy. See rules
> function_call_keyword,
> > > >> >> function_call_nonkeyword, function_call_generic,
> > > >> >> function_call_conflict
> > > >> >> there.
> > > >> >>
> > > >> >> Regards / Mit vielen Grüssen,
> > > >> >> Sergei
> > > >> >>
> > > >> >> --
> > > >> >> __ ___ ___ ____ __
> > > >> >> / |/ /_ __/ __/ __ \/ / Sergei Golubchik
> > <serg@stripped>
> > > >> >> / /|_/ / // /\ \/ /_/ / /__ Principal Software
> > > >> >> Engineer/Server Architect
> > > >> >> /_/ /_/\_, /___/\___\_\___/ Sun Microsystems GmbH, HRB
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> Engels, Dr.
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> > > >> >>
> > > >> >> --
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> > > >> >>
> > > >> >
> > > >> > --
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> > > >> >
> > > >> >
> > > >>
> > > >>
> > > >>
> > > >> --
> > > >> high performance mysql consulting.
> > > >> http://provenscaling.com
> > > >>
> > > >
> > > > --
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> > > >
> > >
> > >
> > >
> > > --
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> > > http://provenscaling.com
> > >
>
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--
Mark Callaghan
mcallaghan@stripped
