Re: Inconsistent DB data in Streaming Replication - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: Inconsistent DB data in Streaming Replication
Date
Msg-id 006301ce35e3$67b0a040$3711e0c0$@kapila@huawei.com
Whole thread Raw
In response to Re: Inconsistent DB data in Streaming Replication  (Samrat Revagade <revagade.samrat@gmail.com>)
Responses Re: Inconsistent DB data in Streaming Replication
List pgsql-hackers
On Wednesday, April 10, 2013 3:42 PM Samrat Revagade wrote:

>>(5) The master then forces a write of the data page related to this
transaction.
> Sorry, this is incorrect. Whenever the master writes the data page it
checks that the WAL record is written in standby till that LSN. 

>> While master is waiting to force a write (point 5) for this data page,
streaming replication continuous.
>> Also other data page writes are not dependent on this particular page
write. So the commit of data >pages are not serialized.

>Sorry, this is incorrect. Streaming replication continuous, master is not
waiting, whenever the master writes the data page it checks that the WAL
record is written in standby till that LSN.

I am not sure it will resolve the problem completely as your old-master can
have some WAL extra then new-master for same timeline. I don't remember
exactly will timeline switch feature
take care of this extra WAL, Heikki can confirm this point?
Also I think this can serialize flush of data pages in checkpoint/bgwriter
which is currently not the case.

With Regards,
Amit Kapila.







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