[hibernate-dev] SingleTableEntityPersister memory footprint in 5.3

[Gail Badner]

I don't think the batching strategies actually changed when we moved to
load plans.

Is the problem that each loader is taking considerably more memory?

On Fri, May 4, 2018 at 5:41 AM, Guillaume Smet <guillaume.smet at gmail.com>
wrote:

> On Fri, May 4, 2018 at 11:48 AM, Sanne Grinovero <sanne at hibernate.org>
> wrote:
>
> > thanks for investigating. Steve in chat mentioned the option of
> > creating these EntityLoaders lazily: as while they need to be reused,
> > it's possible many of them are never really used.
> >
> > I think that's a very interesting observation, is that what you plan to
> > explore?
> >
>
> Yes, it's one of the things we should explore.
>
>
> > I see two difficulties:
> >  - you'd need thredsafe code, yet we don't want barriers on this area.
> > Will probably need features such as lazy set, yet these would need
> > even more objects allocated if you're not careful.
> >  - we always prefer fail-at-boot validation, so we'd need to make sure
> > even if you don't build them all, we can at least make sure we'll be
> > able to build them later.
> >
>
> Well, the idea is to prototype something on the memory usage front, then we
> can discuss further what we want to do with it and if it's worth refining
> it and spending more time on it.
>
> If we end up choosing this path, be sure we'll be bugging you for advice on
> concurrency and performance :).
>
>
> > Additionally there's the idea to see if any such Loader instance could
> > be reused - probably using a cache which we clear at end of bootstrap
> > - yet since Steve mentioned this would be a significant change let's
> > not try to push it in 5.3.
> >
> > Finally, a simple one: I have the impression that loader's Map could
> > be made into a plain array, or a custom structure which would then be
> > ideal to support lazy creation of loaders. With the exception of two
> > special strings - which will needt to be treated specially - all other
> > keys are enums.
> >
>
> Yeah, I'll play with a few ideas and see what I can do. I'm not yet sure if
> not knowing the code base will be a thing in my favor or not. At least I
> don't have preconceived ideas :].
>
>
> > Whatever you choose to try, let's keep significant changes for 6 only :)
> >
>
> Steve was saying that this whole thing wouldn't be an issue in 6.
>
> --
> Guillaume
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