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Re: [Commits] a1ab431: MDEV-7261 - Backport the default autosized value of

 

Hi Sergei,

On Wed, Nov 25, 2015 at 02:11:21PM +0100, Sergei Golubchik wrote:
> Hi, Sergey!
> 
> On Nov 25, Sergey Vojtovich wrote:
> > On Mon, Nov 23, 2015 at 10:44:39AM +0100, Sergei Golubchik wrote:
> > > On Nov 23, Sergey Vojtovich wrote:
> > > > On Mon, Nov 23, 2015 at 10:00:33AM +0100, Sergei Golubchik wrote:
> > > > > On Nov 23, Sergey Vojtovich wrote:
> > > > > 
> > > > > Could there be any other fix for P_S autosizing besides moving all its
> > > > > dependencies to early options?
> > > > No simple solution on my mind. May be initialize PFS with defaults and
> > > > then reinitialize with real values?
> > > 
> > > perfschema creates fixed-size (*) arrays based on these values. And
> > > allocates data mutexes, rwlocks, conditions there.
> > > 
> > > if perfschema data structures are re-initialized, all mutexes/etc have
> > > to be. That's why Marc has created these "early options" in the
> > > first place. To reinitialize only those few mutexes that my_getopt
> > > needs, not half of the server.
> > > 
> > All I can see now is 19 PFS variables depending on table_definition_cache &&
> > table_open_cache && max_connections && open_files_limit values. I couldn't
> > easily track down further dependencies, at least number of allocated arrays
> > basing on these variables is far over 19.
> > 
> > Could you confirm that:
> > 1. we want to fix PFS autosizing along with this patch
> 
> No.
> 
> > 2. we want to avoid early initialization of these 4 server variables and
> >    instead reinitialize PFS when they're autosized
> 
> No.
> 
> 1. PFS autosizing can be fixed later. But assuming it will be fixed, I
> wouldn't want you to do a patch now that will be completely reverted
> when fixing PFS autosizing.
> 
> 2. No, why?
I'm lost now:
- we don't want to fix PFS autosizing along with this patch
  (that is we don't want to make these 4 variables early options right now)
- and we don't want this patch because it will be reverted later
  (though I'd say not reverted, but moved because this logic will stay)

This makes me think that:
- either we don't want to fix this bug until PFS autosizing is fixed first
- or there's another options which I can't think of

What's your thinking?

Thanks,
Sergey


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