On Wed, Aug 23, 2017 at 11:05 AM, Haribabu Kommi <kommi.harib...@gmail.com> wrote: > > > On Mon, Aug 21, 2017 at 7:25 PM, Amit Kapila <amit.kapil...@gmail.com> > wrote: >> >> On Mon, Aug 21, 2017 at 12:58 PM, Haribabu Kommi >> <kommi.harib...@gmail.com> wrote: >> > >> > On Sun, Aug 13, 2017 at 5:17 PM, Amit Kapila <amit.kapil...@gmail.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. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
