maria-developers team mailing list archive

[Sergey Vojtovich <svoj@xxxxxxxxxxx>]

Sergei,

On Thu, Apr 02, 2020 at 11:43:26AM +0200, Sergei Golubchik wrote:
> Hi, Sergey!
> 
> On Apr 01, Sergey Vojtovich wrote:
> > revision-id: 5c26e91f755 (mariadb-10.5.0-70-g5c26e91f755)
> > parent(s): 6daf451415f
> > author: Sergey Vojtovich <svoj@xxxxxxxxxxx>
> > committer: Sergey Vojtovich <svoj@xxxxxxxxxxx>
> > timestamp: 2019-12-25 20:24:25 +0400
> > message:
> > 
> > Cleanup close_all_tables_for_name()
> > 
> > close_all_tables_for_name() is always preceded by
> > wait_while_table_is_used(), which makes tdc_remove_table() redundant.
> > The only (now fixed) exception was close_cached_tables().
> > 
> > Part of MDEV-17882 - Cleanup refresh version
> > 
> > diff --git a/sql/sql_base.cc b/sql/sql_base.cc
> > index 60e2b9957a4..9494c0b7bd2 100644
> > --- a/sql/sql_base.cc
> > +++ b/sql/sql_base.cc
> > @@ -391,13 +391,12 @@ bool close_cached_tables(THD *thd, TABLE_LIST *tables,
> >        if (! table)
> >          continue;
> >  
> > -      if (thd->mdl_context.upgrade_shared_lock(table->mdl_ticket, MDL_EXCLUSIVE,
> > -                                               timeout))
> > +      if (wait_while_table_is_used(thd, table,
> > +                                   HA_EXTRA_PREPARE_FOR_FORCED_CLOSE))
> 
> the comment just above this block says
> 
>     /*
>       If we are under LOCK TABLES, we need to reopen the tables without
>       opening a door for any concurrent threads to sneak in and get
>       lock on our tables. To achieve this we use exclusive metadata
>       locks.
>     */
> 
> how do you achieve it now without the MDL_EXCLUSIVE ?
Well, I didn't remove upgrade to MDL_EXCLUSIVE. It is now done by
wait_while_table_is_used().

Regards,
Sergey