Re: Conflict detection and logging in logical replication

On Thu, Jul 25, 2024 at 12:04 PM Zhijie Hou (Fujitsu)
<houzj(dot)fnst(at)fujitsu(dot)com> wrote:
> Here is the V6 patch set which addressed Shveta and Nisha's comments
> in [1][2][3][4].

Thanks for the patch.
I tested the v6-0001 patch with partition table scenarios. Please
review the following scenario where Pub updates a tuple, causing it to
move from one partition to another on Sub.

Setup:
Pub:
create table tab (a int not null, b int not null);
alter table tab add constraint tab_pk primary key (a,b);
Sub:
create table tab (a int not null, b int not null) partition by range (b);
alter table tab add constraint tab_pk primary key (a,b);
create table tab_1 partition of tab FOR values from (MINVALUE) TO (100);
create table tab_2 partition of tab FOR values from (101) TO (MAXVALUE);

Test:
Pub: insert into tab values (1,1);
Sub: update tab set a=1 where a=1; > just to make it Sub's origin
Sub: insert into tab values (1,101);
Pub: update b=101 where b=1; --> Both 'update_differ' and
'insert_exists' are detected.

For non-partitioned tables, a similar update results in
'update_differ' and 'update_exists' conflicts. After detecting
'update_differ', the apply worker proceeds to apply the remote update
and if a tuple with the updated key already exists, it raises
'update_exists'.
This same behavior is expected for partitioned tables too.

Thanks,
Nisha