maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Aleksey!

On Feb 18, Aleksey Midenkov wrote:
> On Mon, Feb 17, 2020 at 8:23 PM Sergei Golubchik <serg@xxxxxxxxxxx> wrote:
> > On Feb 17, Aleksey Midenkov wrote:
> > > On Sat, Nov 9, 2019 at 12:03 AM Sergei Golubchik <serg@xxxxxxxxxxx> wrote:
> > > >
> > > > 1.
> > > > It should be possible to enable/disable auto-creation.  For
> > > > example, CREATE TABLE ... PARTITION BY SYSTEM_TIME ...
> > > > PARTITIONS AUTO; this solves few problems at once:
> > > > * a user explicitly tells when auto-creation should work
> > >
> > > Done.
> > >
> > > > * you don't need to worry "if this name is already occupied"
> > >
> > > I have to. There can be partitions created by hand.
> >
> > Here I meant that partitions can be either AUTO or manually created.
> > So if a user had specified AUTO there can be no manually added
> > partitions.  Which makes the implementation simpler.
> 
> I believe current implementation is better: compatibility with old
> syntax and existing tables require just to add one keyword to make
> things work. I don't believe one little loop makes it more complex.
> OTOH forced syntax difference is something users nor programmers don't
> like.

I'm just saying, the implementation can be made notably simpler if we
won't allow manually and automatically created partitions in the same
table. But if you want to support that and solve problems that it
creates  - okay.

> > > > * you can define that these partitions can never overflow (for
> > > > INTERVAL)
> > > > * if you know that AUTO partitions never overflow, you can keep
> > > > the old behavior for ALTER TABLE ADD PARTITION.
> > >
> > > Fast ADD is performance consideration. Making data copy on
> > > auto-creation is feature killer.
> >
> > Agree. I meant that if partitions never overflow, then ADD will
> > never need copying.
> 
> Agree. The old behavior will be returned in MDEV-21747.

Great, I'll do a new review when it's done, then.

> > Using the parser in the main thread is easy, we do that in many
> > places. It would be the last reason for me to do a separate thread.
> 
> I'm not familiar with that. Can we run SQL command from another SQL
> command easily?

Not "run SQL command" yet. But "parse SQL command" — yes.
Just grep for "parse_sql" for examples.

Regards,
Sergei
VP of MariaDB Server Engineering
and security@xxxxxxxxxxx