I think this is the nature of "async multi master"...
IMHO, It would be necessary to be "sync multi master" (with two-phase
commit?) to get the behavior you expect.
Atenciosamente,
Edson Carlos Ericksson Richter
Em 04/01/2016 18:09, Riley Berton escreveu:
I have been experimenting with BDR and have a question about how BDR
interacts with transactions.
bdrdemo=# create table thingy (id INT, value TEXT, PRIMARY KEY(id));
CREATE TABLE
bdrdemo=# create table tx_log(id INT, msg TEXT, PRIMARY KEY(id));
CREATE TABLE
bdrdemo=# insert into thingy (id, value) VALUES (1, 'insert from node1');
INSERT 0 1
From node1:
bdrdemo=# begin;
BEGIN
bdrdemo=# update thingy set value='update from node1' where id=1;
UPDATE 1
bdrdemo=# insert into tx_log (id, msg) values (1, 'tx log insert from node1');
INSERT 0 1
bdrdemo=# commit;
COMMIT
Simultaneously from node2:
bdrdemo=# begin;
BEGIN
bdrdemo=# update thingy set value='update from node2' where id=1;
UPDATE 1
bdrdemo=# insert into tx_log (id, msg) values (2, 'tx log insert from node2');
INSERT 0 1
bdrdemo=# commit;
COMMIT
...
bdrdemo=# select * from tx_log ;
id | msg
----+--------------------------
1 | tx log insert from node1
2 | tx log insert from node2
(2 rows)
bdrdemo=# select * from thingy ;
id | value
----+-------------------
1 | update from node2
(1 row)
The conflict on the "thingy" table has resulted in node2 winning based
on last_update wins default resolution. However, both inserts have
applied. My expectation is that the entire TX applies or does not
apply. This expectation is clearly wrong.
Question is: is there a way (via a custom conflict handler) to have the
TX obeyed? I can't see a way to even implement a simple bank account
database that changes multiple tables in a single transaction without
having the data end up in an inconsistent state. Am I missing something
obvious here?
Thanks in advance for any help.
riley
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