Re: [HACKERS] UPDATE of partition key
| От | Rajkumar Raghuwanshi |
|---|---|
| Тема | Re: [HACKERS] UPDATE of partition key |
| Дата | |
| Msg-id | CAKcux6=z38gH4K6YAFi+Yvo5tHTwBL4tam4VM33CAPZ5dDMk1Q@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [HACKERS] UPDATE of partition key (Amit Khandekar <amitdkhan.pg@gmail.com>) |
| Ответы |
Re: [HACKERS] UPDATE of partition key
|
| Список | pgsql-hackers |
On Tue, Jul 25, 2017 at 3:54 PM, Amit Khandekar <amitdkhan.pg@gmail.com> wrote:
On 25 July 2017 at 15:02, Rajkumar Raghuwanshi
<rajkumar.raghuwanshi@enterprisedb.com> wrote:
> On Mon, Jul 24, 2017 at 11:23 AM, Amit Khandekar <amitdkhan.pg@gmail.com>
> wrote:
>>
>>
>> Attached update-partition-key_v13.patch now contains this
>> make_resultrels_ordered.patch changes.
>>
>
> I have applied attach patch and got below observation.
>
> Observation : if join producing multiple output rows for a given row to be
> modified. I am seeing here it is updating a row and also inserting rows in
> target table. hence after update total count of table got incremented.
Thanks for catching this Rajkumar.
So after the row to be updated is already moved to another partition,
when the next join output row corresponds to the same row which is
moved, that row is now deleted, so ExecDelete()=>heap_delete() gets
HeapTupleSelfUpdated, and this is not handled. So even when
ExecDelete() finds that the row is already deleted, we still call
ExecInsert(), so a new row is inserted. In ExecDelete(), we should
indicate that the row is already deleted. In the existing patch, there
is a parameter concurrenty_deleted for ExecDelete() which indicates
that the row is concurrently deleted. I think we can make this
parameter for both of these purposes so as to avoid ExecInsert() for
both these scenarios. Will work on a patch.
Thanks Amit.
Got one more observation : update... returning is not working with whole row reference. please take a look.
postgres=# create table part (a int, b int) partition by range(a);
CREATE TABLE
postgres=# create table part_p1 partition of part for values from (minvalue) to (0);
CREATE TABLE
postgres=# create table part_p2 partition of part for values from (0) to (maxvalue);
CREATE TABLE
postgres=# insert into part values (10,1);
INSERT 0 1
postgres=# insert into part values (20,2);
INSERT 0 1
postgres=# update part t1 set a = b returning t1;
ERROR: unexpected whole-row reference found in partition key
Got one more observation : update... returning is not working with whole row reference. please take a look.
postgres=# create table part (a int, b int) partition by range(a);
CREATE TABLE
postgres=# create table part_p1 partition of part for values from (minvalue) to (0);
CREATE TABLE
postgres=# create table part_p2 partition of part for values from (0) to (maxvalue);
CREATE TABLE
postgres=# insert into part values (10,1);
INSERT 0 1
postgres=# insert into part values (20,2);
INSERT 0 1
postgres=# update part t1 set a = b returning t1;
ERROR: unexpected whole-row reference found in partition key
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