Re: Transactions involving multiple postgres foreign servers, take 2 - Mailing list pgsql-hackers

From Masahiro Ikeda
Subject Re: Transactions involving multiple postgres foreign servers, take 2
Date
Msg-id bffee891521e583cb81831ac406b9707@oss.nttdata.com
Whole thread Raw
In response to Re: Transactions involving multiple postgres foreign servers, take 2  (Fujii Masao <masao.fujii@oss.nttdata.com>)
Responses Re: Transactions involving multiple postgres foreign servers, take 2  (Masahiko Sawada <masahiko.sawada@2ndquadrant.com>)
List pgsql-hackers
> I've attached the latest version patches. I've incorporated the review
> comments I got so far and improved locking strategy.

I want to ask a question about streaming replication with 2PC.
Are you going to support 2PC with streaming replication?

I tried streaming replication using v23 patches.
I confirm that 2PC works with streaming replication,
which there are primary/standby coordinator.

But, in my understanding, the WAL of "PREPARE" and
"COMMIT/ABORT PREPARED" can't be replicated to the standby server in 
sync.

If this is right, the unresolved transaction can be occurred.

For example,

1. PREPARE is done
2. crash primary before the WAL related to PREPARE is
    replicated to the standby server
3. promote standby server // but can't execute "ABORT PREPARED"

In above case, the remote server has the unresolved transaction.
Can we solve this problem to support in-sync replication?

But, I think some users use async replication for performance.
Do we need to document the limitation or make another solution?

Regards,

-- 
Masahiro Ikeda
NTT DATA CORPORATION



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