maria-developers team mailing list archive

[Aleksey Midenkov <midenok@xxxxxxxxx>]

Hi, Sergei!

On Mon, Dec 6, 2021 at 11:22 PM Sergei Golubchik <serg@xxxxxxxxxxx> wrote:
>
> Hi, Aleksey!
>
> On Dec 05, Aleksey Midenkov wrote:
> > > > diff --git a/sql/sql_base.cc b/sql/sql_base.cc
> > > > index ac22a63bdba..459edb614f7 100644
> > > > --- a/sql/sql_base.cc
> > > > +++ b/sql/sql_base.cc
> > > > @@ -4203,6 +4444,15 @@ bool open_tables(THD *thd, const DDL_options_st &options,
> > > >      }
> > > >
> > > >    thd->current_tablenr= 0;
> > > > +
> > > > +#ifdef WITH_PARTITION_STORAGE_ENGINE
> > > > +  if (!thd->stmt_arena->is_conventional())
> > > > +  {
> > > > +    for (tables= *start; tables; tables= tables->next_global)
> > > > +      tables->vers_skip_create= false;
> > > > +  }
> > >
> > > This looks a bit like an overkill, you do it for every prepare,
> > > while auto-adding a partition is a rare event, as you said.
> > >
> > > May be you can do instead in TABLE::vers_switch_partition
> > >
> > >  uint *create_count= !thd->stmt_arena->is_conventional() &&
> > >                      table_list->vers_skip_create ?
> >
> > No, this is inside backoff action loop. That will interfere with the
> > normal vers_skip_create algorithm (which also applies to PS, SP). The
> > goal of the above code is to reset vers_skip_create from the previous
> > statement execution.
>
> In that case you can use an auto-resetting value, like,
> if tables->vers_skip_create == thd->query_id it means, "skip".
> That is vers_skip_create must be of query_id_t. You set it with
> tables->vers_skip_create= thd->query_id;
> And on the next statement it automatically expires.
>
> This semantics is a bit more complex than boolean, so it'd need a
> comment, like
>
>   /*
>       Protect single thread from repeating partition auto-create over
>       multiple share instances (as the share is closed on backoff action).
>       Skips auto-create only for one given query id.
>   */
>   query_id_t    vers_skip_create;

Done! Thanks for the tip.

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



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