Re: Proposal for 9.1: WAL streaming from WAL buffers

On Wed, Jul 7, 2010 at 6:44 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> On 7/6/10 4:44 PM, Robert Haas wrote:
>> To recap the previous discussion on this thread, we ended up changing
>> the behavior of 9.0 so that it only sends WAL which has been written
>> to the OS *and flushed*, because sending unflushed WAL to the standby
>> is unsafe.  The standby can get ahead of the master while still
>> believing that the databases are in sync, due to the fact that after
>> an SR reconnect we rewind to the start of the current WAL segment.
>> This results in a silently corrupt standby database.
>
> What was the final decision on behavior if fsync=off?

I'm not sure we made any decision, per se, but if you use fsync=off in
combination with SR and experience an unexpected crash-and-reboot on
the master, you will be sad.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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