On 2020/07/15 15:06, Masahiko Sawada wrote:
On Tue, 14 Jul 2020 at 09:08, Masahiro Ikeda <ikeda...@oss.nttdata.com> wrote:
I've attached the latest version patches. I've incorporated the review
comments I got so far and improved locking strategy.
Thanks for updating the patch!
I have three questions about the v23 patches.
1. messages related to user canceling
In my understanding, there are two messages
which can be output when a user cancels the COMMIT command.
A. When prepare is failed, the output shows that
committed locally but some error is occurred.
```
postgres=*# COMMIT;
^CCancel request sent
WARNING: canceling wait for resolving foreign transaction due to user
request
DETAIL: The transaction has already committed locally, but might not
have been committed on the foreign server.
ERROR: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
CONTEXT: remote SQL command: PREPARE TRANSACTION
'fx_1020791818_519_16399_10'
```
B. When prepare is succeeded,
the output show that committed locally.
```
postgres=*# COMMIT;
^CCancel request sent
WARNING: canceling wait for resolving foreign transaction due to user
request
DETAIL: The transaction has already committed locally, but might not
have been committed on the foreign server.
COMMIT
```
In case of A, I think that "committed locally" message can confuse user.
Because although messages show committed but the transaction is
"ABORTED".
I think "committed" message means that "ABORT" is committed locally.
But is there a possibility of misunderstanding?
No, you're right. I'll fix it in the next version patch.
I think synchronous replication also has the same problem. It says
"the transaction has already committed" but it's not true when
executing ROLLBACK PREPARED.
Yes. Also the same message is logged when executing PREPARE TRANSACTION.
Maybe it should be changed to "the transaction has already prepared".
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
