maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Alexander!

On Dec 23, Alexander Barkov wrote:
> Hi Kristian, Sergei.
> What about this plan:
> 
> 1. In 10.0:
> 
> a. Make "ALTER TABLE t1 FORCE" fully rebuild the table
>     and change old DECIMAL to new DECIMAL.

What about DECIMAL(200,30)? What to convert this to?
Perhaps that should always require an explicit manual

  ALTER TABLE t1 MODIFY f1 DECIMAL(N,M) ?

> b. Keep "CHECK TABLE t1 FOR UPGRADE" to still return a line with
>     Msg_type=status and Msg_text=OK, but also add new lines with
>     Msg_type=note and Msg_text telling something like: "The table
>     'db.table' has deprecated columns types incompatible with
>     Row-based replication." "REPAIR TABLE is recommended. Note, this
>     can take some time.".

Why status OK? So that mysql_upgrade would not upgrade them
automatically?

> c. mysql_upgrade will NOT upgrade tables with the old DECIMAL
>     automatically, because they will still be reported as "OK".
> 
>     But mysql_upgrade should detects and prints the new notes
>     in the "CHECK TABLE t1 FOR UPGRADE" output.
> 
> d. Make the master running with --binlog-format=row refuse to do any
>     INSERT/UPDATE/ALTER or any other queries that can modify a table
>     with the old DECIMAL.
> 
>     Also, make "mysqld --binlog-format=row" disallow queries like:
>     "CREATE TABLE t2 AS SELECT old_decimal FROM t1";
> 
>     Make it print an error:
>     "The table 'db.table' has deprecated columns types incompatible
>     with Row-based replication."
> 
>     (the same text with #b, but this time an error instead of a note).
> 
>     Note, one will have to stop binary logging, upgrade the table,
>     and restart mysqld with binary logging again.

I leave it to Kristian...

> e. A SELECT from a table with the old DECIMAL should probably also
>     print a warning, to give the user another chance to know about the
>     problem.

Hmm, I'm not sure it's a good idea. SELECT is perfectly safe.
And warnings should rather be used sparingly.

> f. Make INFORMATION_SCHEMA.COLUMNS somehow print information about the
>     deprecated data types (in DATA_TYPE or COLUMN_TYPE or
>     COLUMN_COMMENT).

Not COLUMN_COMMENT or COLUMN_COMMENT. But DATA_TYPE or - better -
EXTRA - that should be ok.

> 2. In 10.1
>     Change "b" to return Msg_type=error and Mst_text=
>     "Table upgrade required. Please do "REPAIR TABLE `tablename`" or dump/reload to fix it!"
>     This will also force mysql_upgrade to rebuild tables with the old
>     DECIMAL automatically.

That's kind of ok, but again, how to auto-convert a DECIMAL(200,30) column?

Regards,
Sergei