Re: Inadequate thought about buffer locking during hot standby replay

On Sun, Nov 11, 2012 at 6:24 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I already pointed out the inconsistency in heap_xlog_freeze about
> whether a cleanup lock is needed.  As is, this patch uses a cleanup
> lock, but I suspect that a regular lock is sufficient --- comments?

Well, according to storage/buffer/README:

1. To scan a page for tuples, one must hold a pin and either shared or
exclusive content lock.  To examine the commit status (XIDs and status bits)
of a tuple in a shared buffer, one must likewise hold a pin and either shared
or exclusive lock.

That does indeed make it sound like an x-lock is enough.

-- 
Robert Haas
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