Amit, thanks for comments!
> 1.
> +#define InitNonVacuumableSnapshot(snapshotdata) \
> + do { \
> + (snapshotdata).satisfies = HeapTupleSatisfiesNonVacuumable; \
> + (snapshotdata).xmin = RecentGlobalDataXmin; \
> + } while(0)
> +
>
> Can you explain and add comments why you think RecentGlobalDataXmin is
> the right to use it here? As of now, it seems to be only used for
> pruning non-catalog tables.
Can you explain me, what value for xmin should be used there?
> 2.
> +bool
> +HeapTupleSatisfiesNonVacuumable(HeapTuple htup, Snapshot snapshot,
> + Buffer buffer)
> +{
> + return HeapTupleSatisfiesVacuum(htup, snapshot->xmin, buffer)
> + != HEAPTUPLE_DEAD;
> +}
> +
>
> Add comments on top of this function and for the sake of consistency
> update the file header as well (Summary of visibility functions:)
Yes, i will add comments and send new patch.
