Re: UPDATE of partition key

On Mon, May 15, 2017 at 5:28 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Fri, May 12, 2017 at 3:07 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>> I agree with you that it might not be straightforward to make it work,
>> but now that earliest it can go is v11, do we want to try doing
>> something other than just documenting it. What I could read from this
>> e-mail thread is that you are intending towards just documenting it
>> for the first cut of this feature. However, both Greg and Simon are of
>> opinion that we should do something about this and even patch Author
>> (Amit Khandekar) has shown some inclination to do something about this
>> point (return error to the user in some way), so I think we can't
>> ignore this point.
>>
>> I think now that we have some more time, it is better to try something
>> based on a couple of ideas floating in this thread to address this
>> point and see if we can come up with something doable without a big
>> architecture change.
>>
>> What is your take on this point now?
>
> I still don't think it's worth spending a bit on this, especially not
> with WARM probably gobbling up multiple bits. Reclaiming the bits
> seems like a good idea, but spending one on this still seems to me
> like it's probably not the best use of our increasingly-limited supply
> of infomask bits.
>

I think we can do this even without using an additional infomask bit.
As suggested by Greg up thread, we can set InvalidBlockId in ctid to
indicate such an update.

> Now, Simon and Greg may still feel otherwise, of
> course.
>
> I could get behind providing an option to turn this behavior on and
> off at the level of the partitioned table.
>

Sure that sounds like a viable option and we can set the default value
as false. However, it might be better if we can detect the same
internally without big changes.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com