Re: preserving forensic information when we freeze

On Thu, Jan 2, 2014 at 2:56 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> On Thu, Jan 2, 2014 at 2:44 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> As I commented to Robert, the page-at-a-time behavior of pageinspect
>>> is not an API detail we'd want to copy for this. I envision something
>>> like
>>>
>>> select hdr.*, foo.*
>>> from tuple_header_details('foo'::regclass) as hdr
>>> left join foo on hdr.ctid = foo.ctid;
>>>
>>> On a large table you might want a version that restricts its scan
>>> to pages M through N, but that's just optimization. More useful
>>> would be to improve the planner's intelligence about joins on ctid ...
>
>> /me blinks.
>
>> Surely you're not serious. That's going to scan the whole darn table
>> even if we only want the details for one row.
>
> And? The complaint about the other function was that it was inefficient
> when getting the details for a whole table, so I don't think you can
> complain about an approach that handles that case well. Use the other
> function if you just want info for one row (that you can see).

Well, that's fair enough. I don't mind having two functions. Should
the whole-table function also include invisible tuples?

--
Robert Haas
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