Re: silent data loss with ext4 / all current versions

On Sat, Feb 6, 2016 at 2:11 AM, Tomas Vondra
<tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> On 02/04/2016 09:59 AM, Michael Paquier wrote:
>>
>> On Tue, Feb 2, 2016 at 9:59 AM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>>>
>>> On 2016-02-02 09:56:40 +0900, Michael Paquier wrote:
>>>>
>>>> And there is no actual risk of data loss
>>>
>>>
>>> Huh?
>>
>>
>> More precise: what I mean here is that should an OS crash or a power
>> failure happen, we would fall back to recovery at next restart, so we
>> would not actually *lose* data.
>
>
> Except that we actually can't perform the recovery properly because we may
> not have the last WAL segment (or multiple segments), so we can't replay the
> last batch of transactions. And we don't even notice that.

Still the data is here... But well. I won't insist. Tomas, could you
have a look at the latest patch I wrote? It would be good to get fresh
eyes on it. We could work on a version for ~9.4 once we have a clean
approach for master/9.5.
--
Michael