Re: Why we lost Uber as a user

On 08/03/2016 11:23 AM, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> I don't think they are saying that logical replication is more
>> reliable than physical replication, nor do I believe that to be true.
>> I think they are saying that if logical corruption happens, you can
>> fix it by typing SQL statements to UPDATE, INSERT, or DELETE the
>> affected rows, whereas if physical corruption happens, there's no
>> equally clear path to recovery.
>
> Well, that's not an entirely unreasonable point, but I dispute the
> implication that it makes recovery from corruption an easy thing to do.
> How are you going to know what SQL statements to issue?  If the master
> database is changing 24x7, how are you going to keep up with that?
>
> I think the realistic answer if you suffer replication-induced corruption
> is usually going to be "re-clone that slave", and logical rep doesn't
> really offer much gain in that.

Yes, it actually does. The ability to unsubscribe a set of tables, 
truncate them and then resubscribe them is vastly superior to having to 
take a base backup.

JD

>
>             regards, tom lane
>
>


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