maria-developers team mailing list archive

[Sergey Vojtovich <svoj@xxxxxxxxxxx>]

Hi Sergei,

On Wed, Jan 29, 2014 at 10:33:55PM +0100, Sergei Golubchik wrote:
> Hi, Sergey!
> 
> On Jan 29, Sergey Vojtovich wrote:
> > At lp:maria/10.0
> > 
> > ------------------------------------------------------------
> > revno: 3966
> > revision-id: svoj@xxxxxxxxxxx-20140129083115-jwye7zfyncrq9crs
> > parent: svoj@xxxxxxxxxxx-20140124075326-d7twer07e0bu42b5
> > committer: Sergey Vojtovich <svoj@xxxxxxxxxxx>
> > branch nick: 10.0
> > timestamp: Wed 2014-01-29 12:31:15 +0400
> > message:
> >   MDEV-5492 - Reduce usage of LOCK_open: TABLE::in_use
> >   
> >   Move TABLE::in_use out of LOCK_open.
> >   
> >   This is done with assumtion that foreign threads accessing TABLE::in_use
> >   will only need consistent value _after_ marking table for flush and purging
> >   unused table instances. In this case TABLE::in_use will always point to a
> >   valid thread object.
> 
> I believe I was able to understand what you were doing here :)
> Seems ok.
> 
> The assumption above looks a bit risky without any way to enforce it.
> 
> Perhaps you could make in_use private (renaming to, say, m_in_use)
> and add an inline getter method TABLE::in_use() that in debug builds
> will assert that your assumption holds?
Like DBUG_ASSERT(table->in_use == current_thd || (table->s->flushed && table->in_use))?
I would gladly do that, but that's quite big change which will also affect many
storage engines, at least federated, maria, myisam, sphinx, oqgraph, connect,
merge, spider, cassandra, tokudb.

If it isn't a problem I'd prefer to create a separate patch.

Thanks,
Sergey