Re: Pluggable storage

On Wed, Aug 23, 2017 at 11:59 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:

> On Wed, Aug 23, 2017 at 11:05 AM, Haribabu Kommi
> <kommi(dot)haribabu(at)gmail(dot)com> wrote:
> >
> >
> > On Mon, Aug 21, 2017 at 7:25 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> > wrote:
> >>
> >> On Mon, Aug 21, 2017 at 12:58 PM, Haribabu Kommi
> >> <kommi(dot)haribabu(at)gmail(dot)com> wrote:
> >> >
> >> > On Sun, Aug 13, 2017 at 5:17 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com
> >
> >> > wrote:
> >> >>
> >> >>
> >> >> Also, it is quite possible that some of the storage Am's don't even
> >> >> want to return bool as a parameter from HeapTupleSatisfies* API's. I
> >> >> guess what we need here is to provide a way so that different storage
> >> >> am's can register their function pointer for an equivalent to
> >> >> satisfies function. So, we need to change
> >> >> SnapshotData.SnapshotSatisfiesFunc in some way so that different
> >> >> handlers can register their function instead of using that directly.
> >> >> I think that should address the problem you are planning to solve by
> >> >> omitting buffer parameter.
> >> >
> >> >
> >> > Thanks for your suggestion. Yes, it is better to go in the direction
> of
> >> > SnapshotSatisfiesFunc.
> >> >
> >> > I verified the above idea of implementing the Tuple visibility
> functions
> >> > and assign them into the snapshotData structure based on the snapshot.
> >> >
> >> > The Tuple visibility functions that are specific to the relation are
> >> > available
> >> > with the RelationData structure and this structure may not be
> available,
> >> >
> >>
> >> Which functions are you referring here? I don't see anything in
> >> tqual.h that uses RelationData.
> >
> >
> >
> > With storage API's, the tuple visibility functions are available with
> > RelationData
> > and those are needs used to update the SnapshotData structure
> > SnapshotSatisfiesFunc member.
> >
> > But the RelationData is not available everywhere, where the snapshot is
> > created,
> > but it is available every place where the tuple visibility is checked.
> So I
> > just changed
> > the way of checking the tuple visibility with the information of
> snapshot by
> > calling
> > the corresponding tuple visibility function from RelationData.
> >
> > If SnapshotData provides MVCC, then the MVCC specific tuple visibility
> > function from
> > RelationData is called. The SnapshotSatisfiesFunc member is changed to a
> > enum
> > that holds the tuple visibility type such as MVCC, DIRTY, SELF and etc.
> > Whenever
> > the visibility check is needed, the corresponding function is called.
> >
>
> It will be easy to understand and see if there is some better
> alternative once you have something in the form of a patch.

Sorry for the delay.

I will submit the new patch series with all comments given
in the upthread to the upcoming commitfest.

Regards,
Hari Babu
Fujitsu Australia