Re: [HACKERS] UPDATE of partition key

On 9 June 2017 at 19:10, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Thu, Jun 8, 2017 at 10:40 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Thu, Jun 8, 2017 at 7:01 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>>> On Thu, Jun 8, 2017 at 1:33 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>>>> On Wed, Jun 7, 2017 at 5:46 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>>>>> As far as I understand, it is to ensure that for deleted rows, nothing
>>>>> more needs to be done.  For example, see the below check in
>>>>> ExecUpdate/ExecDelete.
>>>>> if (!ItemPointerEquals(tupleid, &hufd.ctid))
>>>>> {
>>>>> ..
>>>>> }
>>>>> ..
>>>>>
>>>>> Also a similar check in ExecLockRows.  Now for deleted rows, if the
>>>>> t_ctid wouldn't point to itself, then in the mentioned functions, we
>>>>> were not in a position to conclude that the row is deleted.
>>>>
>>>> Right, so we would have to find all such checks and change them to use
>>>> some other method to conclude that the row is deleted.  What method
>>>> would we use?
>>>
>>> I think before doing above check we can simply check if ctid.ip_blkid
>>> contains InvalidBlockNumber, then return an error.
>>
>> Hmm, OK.  That case never happens today?
>>
>
> As per my understanding that case doesn't exist.  I will verify again
> once the patch is available.  I can take a crack at it if Amit
> Khandekar is busy with something else or is not comfortable in this
> area.

Amit, I was going to have a look at this, once I finish with the other
part. I was busy on getting that done first. But your comments/help
are always welcome.

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



-- 
Thanks,
-Amit Khandekar
EnterpriseDB Corporation
The Postgres Database Company