| From: | Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> |
|---|---|
| To: | Masahiro Ikeda <ikedamsh(at)oss(dot)nttdata(dot)com>, pgsql-hackers(at)lists(dot)postgresql(dot)org |
| Cc: | masahiko(dot)sawada(at)2ndquadrant(dot)com, amit(dot)kapila16(at)gmail(dot)com, m(dot)usama(at)gmail(dot)com, sulamul(at)gmail(dot)com, horikyota(dot)ntt(at)gmail(dot)com, sawada(dot)mshk(at)gmail(dot)com, alvherre(at)2ndquadrant(dot)com, thomas(dot)munro(at)gmail(dot)com, ildar(at)adjust(dot)com, horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp, chris(dot)travers(at)adjust(dot)com, robertmhaas(at)gmail(dot)com, tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com, Tatsuo Ishii <ishii(at)sraoss(dot)co(dot)jp> |
| Subject: | Re: Transactions involving multiple postgres foreign servers, take 2 |
| Date: | 2020-07-14 02:19:36 |
| Message-ID: | b4b3105f-39cc-df2b-55ac-4dcfa8c303da@oss.nttdata.com |
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| Lists: | pgsql-hackers |
On 2020/07/14 9:08, Masahiro Ikeda 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!
+1
I'm interested in these patches and now studying them. While checking
the behaviors of the patched PostgreSQL, I got three comments.
1. We can access to the foreign table even during recovery in the HEAD.
But in the patched version, when I did that, I got the following error.
Is this intentional?
ERROR: cannot assign TransactionIds during recovery
2. With the patch, when INSERT/UPDATE/DELETE are executed both in
local and remote servers, 2PC is executed at the commit phase. But
when write SQL (e.g., TRUNCATE) except INSERT/UPDATE/DELETE are
executed in local and INSERT/UPDATE/DELETE are executed in remote,
2PC is NOT executed. Is this safe?
3. XACT_FLAGS_WROTENONTEMPREL is set when INSERT/UPDATE/DELETE
are executed. But it's not reset even when those queries are canceled by
ROLLBACK TO SAVEPOINT. This may cause unnecessary 2PC at the commit phase.
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
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