Re: WIP patch for hint bit i/o mitigation

On Tue, 2012-11-06 at 17:55 -0600, Merlin Moncure wrote:
> So given that -- the patch simple adds an extra check when/where hint
> bit status is checked in the visibility routines (currently, only
> HeapTupleSatisfiesMVCC is done but all the applicable visibility
> routines should be done).  Basically, the way it works is like this:
> 
> *) is hint bit set?
> *) if not? does the examined xid match the last examined one?
> *) if so, and the cached hint bit matches the one want, proceeed as if
> hint bit was set

Can you clarify the difference between this and
cachedFetchXid/cachedFetchXidStatus? Do we need to keep those if your
patch is accepted?

Regards,
	Jeff Davis