maria-developers team mailing list archive

["md@xxxxxxxxxxxxx" <md@xxxxxxxxxxxxx>]

Monty:

I received your email and am re-posting to the maria developers list.

It is truly amazing that maria developers are HAPPY with replication as 
it stands right now.
binary logs, Single SLAVE reading from individual masters, bla-bla-bla.....

All the current replication code is like walking on the edge of a cliff, 
anything goes wrong
and the replication process STOPS with an error.  And a HUMAN BEING must 
wake up from their
blissful sleep to get the process started again and figure out what 
happened.

And I just LOVE having to:

LOCK TABLES;
RESET MASTER
SET SLAVE OFF;
MYSQLDUMP;
COPY FILES TO SLAVE;
SET MASTER TO 'sql_log_bin=45678945";
SET SLAVE ON;
SECONDS BEHIND MASTER...
WRITE A THESIS FOR MY PHD IN ROCKET SCIENCE
Oh my GOD!!!!!!

What an absolute nightmare of a design, it works, just not well.

I have not made an in depth study of galera, but I refuse to make 
replication another research project,
replication should be EASY, auto-healing, self analyzing, N-MASTER and 
with simple source code.

I will open source the files that I use to change the MYSQLD daemon.

The best way to debug MariaDB on Linux is to run the program in Netbeans 
7.1.2.
You can even give it command line parameters to work against
a currently installed system with the data/conf files in place.

Your trace idea is very nice, but there is nothing like STEPPING THROUGH 
the code
in NetBeans/GDB in a nice IDE instead of cryptic command line GDB.

Cheers,

md


On 1/2/2013 5:21 AM, Michael Widenius wrote:
> Hi!
>
> A better place to send emails like this is to
> maria-developers@xxxxxxxxxxxxxxxxxxx;  That way you can get all
> MariaDB developers to answer you questions.
>
> > > > > > "md" == md  <md@xxxxxxxxxxxxx> writes:
> md> Hello:
> md> Does anybody know the name(s) of the source files I could find the code
> md> that processes the Table/Procedure Drop/Create/Update, Alter Table, etc
> md> statements.
>
> md> I want to intercept these SQL statement calls in mysqld before
> md> they get sent to the specific storage engine like Aria or Xtradb.
>
> sql_parse.cc proably contains the code you are looking for.
> Another place to look is in the the current replication code,
> ie the sql_repl.cc
>
> md> I am working on an asynchronous external replication daemon
> md> that handles all of the data and structure synchronization
> md> replication issues (N-master-master, Hot Insert Master additions, DDL
> md> changes, etc)
>
> Sounds very intersting.
> Is this a open source project ?
>
> md> This is one of the missing pieces of the puzzle for MariaDB.
> md> (oh yeah, mysql does not exist to me anymore, only Aria/Xtradb)
>
> :)
>
> md> I need to have the mysqld daemon issue a signal that a structural change
> md> has taken place and the external replication daemon will pick it up
> md> and handle all the changes processing across ALL the masters (WITHOUT A
> md> HUMAN BEING INVOLVED!!!!)
>
> md> I figured I would ask since most of you are fluent in the source
> md> code and just know where everything is, you would know right away.
>
> That's ok, but best way to get quick responce is to ask on the
> maria-developers list or at #maria channel on Freenode.
>
> md> I am using MariaDB 5.5.28a from source.
>
> On thing you can do is:
>
> ./BUILD/compile-pentium-debug-max
> mysqld --debug
>
> And then start 'mysql' and execute a CREATE TABLE command.
>
> You can find then find a full trace of all executed functions in:
> /tmp/mysqld.trace
>
> That's probably one of the best ways to learn how MariaDB works.
>
> See:
>
> https://kb.askmonty.org/en/creating-a-trace-file/
>
> Regards,
> Monty