From: | Kevin Grittner <kgrittn(at)ymail(dot)com> |
---|---|
To: | Kevin Grittner <kgrittn(at)ymail(dot)com>, Alexander Korotkov <aekorotkov(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: pg_dump with both --serializable-deferrable and -j |
Date: | 2015-01-28 14:54:15 |
Message-ID: | 1048360359.1100308.1422456855640.JavaMail.yahoo@mail.yahoo.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Kevin Grittner <kgrittn(at)ymail(dot)com> wrote:
> Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
>> Could we start snapshot-importing transaction with repeatable
>> read isolation level?
>
> You can if you don't use the option which specifies that you want
> serializable behavior. Why specify --serializable-deferrable if
> you don't?
>
>> AFAICS, they should read exactly same data as snapshot-exporting
>> serializable transaction.
>
> Sort of. The behavior once they have a snapshot and are running is
> the same; the difference is whether the snapshot can see a
> transient state which would not be consistent with some serial
> order of transaction execution.
Oh, wait; on a re-read I think I may have misunderstood the question.
If you are talking about having pg_dump acquire a safe snapshot and
have cooperating processes in the same pg_dump run use that
snapshot in repeatable read transactions, then yes -- that would
work. As long as a repeatable read transaction is using a safe
snapshot it will not see any anomalies. That would be a better
solution if it can be done. Do you have any code to suggest, or
should I look at writing it?
--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
From | Date | Subject | |
---|---|---|---|
Next Message | Andres Freund | 2015-01-28 15:07:04 | Re: pg_dump with both --serializable-deferrable and -j |
Previous Message | Kevin Grittner | 2015-01-28 14:43:35 | Re: pg_dump with both --serializable-deferrable and -j |