Re: SSI patch version 14

On Mon, 2011-01-31 at 13:32 -0600, Kevin Grittner wrote:
> Ah, now I see what you're talking about. Take a look at where that
> "valid" flag come from -- the CheckForSerializableConflictOut are
> all place right after calls to HeapTupleSatisfiesVisibility. The
> "valid" value is what HeapTupleSatisfiesVisibility returned. Is it
> possible that the hint bits will not be accurate right after that?
> With that in mind, do you still see a problem with how things are
> currently done?

Oh, ok. The staleness of the hint bit was a fairly minor point though.

Really, I think this should be using HTSV to separate concerns better
and improve readability. My first reaction was to try to find out what
the function was doing that's special. If it is doing something special,
and HTSV is not what you're really looking for, a comment to explain
would be helpful.

As an example, consider that Robert Haas recently suggested using an
infomask bit to mean frozen, rather than actually removing the xid, to
save the xid as forensic information. If that were to happen, your code
would be reading an xid that may have been re-used.

Regards,
Jeff Davis