Re: UPDATE of partition key

On 11 September 2017 at 21:12, Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> On Thu, Sep 7, 2017 at 11:41 AM, Amit Khandekar <amitdkhan(dot)pg(at)gmail(dot)com> wrote:
>> On 6 September 2017 at 21:47, Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
>> Actually, since transition tables came in, the functions like
>> ExecARUpdateTriggers() or ExecARInsertTriggers() have this additional
>> purpose of capturing transition table rows, so that the images of the
>> tables are visible when statement triggers are fired that refer to
>> these transition tables. So in the above code, these functions only
>> capture rows, they do not add any event for firing any ROW triggers.
>> AfterTriggerSaveEvent() returns without adding any event if it's
>> called only for transition capture. So even if UPDATE row triggers are
>> defined, they won't get fired in case of row movement, although the
>> updated rows would be captured if transition tables are referenced in
>> these triggers or in the statement triggers.
>>
>
> Ok then I have one more question,
>
> With transition table, we can only support statement level trigger

Yes, we don't support row triggers with transition tables if the table
is a partition.

> and for update
> statement, we are only going to execute UPDATE statement level
> trigger? so is there
> any point of making transition table entry for DELETE/INSERT trigger
> as those transition
> table will never be used.

But the statement level trigger function can refer to OLD TABLE and
NEW TABLE, which will contain all the OLD rows and NEW rows
respectively. So the updated rows of the partitions (including the
moved ones) need to be captured. So for OLD TABLE, we need to capture
the deleted row, and for NEW TABLE, we need to capture the inserted
row.

In the regression test update.sql, check how the statement trigger
trans_updatetrig prints all the updated rows, including the moved
ones.

>
> --
> Regards,
> Dilip Kumar
> EnterpriseDB: http://www.enterprisedb.com

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