Re: loss of transactions in streaming replication

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>

To: Fujii Masao <masao.fujii@gmail.com>

Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2011-10-21T03:01:52Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Send status updates back from standby server to master, indicating how far
- b186523fd97c 9.1.0 cited
Allow bidirectional copy messages in streaming replication mode.
- d3d414696f39 9.1.0 cited

On Thu, Oct 20, 2011 at 9:51 PM, Fujii Masao <masao.fujii@gmail.com> wrote:
> On Thu, Oct 20, 2011 at 1:05 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> OK, so this is an artifact of the changes to make libpq communication
>> bidirectional.  But I'm still confused about where the error is coming
>> from.  In your OP, you wrote "In 9.2dev and 9.1, when walreceiver
>> detects an error while sending data to WAL stream, it always emits
>> ERROR even if there are data available in the receive buffer."  So
>> that implied to me that this is only going to trigger if you have a
>> shutdown together with an awkwardly-timed error.  But your scenario
>> for reproducing this problem doesn't seem to involve an error.
>
> Yes, my scenario doesn't cause any real error. My original description was
> misleading. The following would be closer to the truth:
>
>    "In 9.2dev and 9.1, when walreceiver detects the termination of replication
>    connection while sending data to WAL stream, it always emits ERROR
>    even if there are data available in the receive buffer."

Ah, OK.  I think I now agree that this is a bug and that we should fix
and back-patch.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company