Re: Horizontal scalability/sharding

On 2015-09-02 PM 01:28, Amit Kapila wrote:
>> On Tue, Sep 1, 2015 at 9:48 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>>>
>>> I'm not averse to making the "connect to the remote nodes" part of
>>> this solution use something other than the FDW infrastructure at some
>>> point in time if somebody's prepared to build something better. On
>>> the other hand, I think it's extremely clear that the FDW
>>> infrastructure has a large amount of potential upon which we have
>>> thoroughly failed to capitalize. Patches have already been written
>>> for UPDATE/DELETE pushdown and for join pushdown.
>
> Will pushing down writes (Update/Delete) sufficient to maintain sane locking
> behaviour and deadlock detection that can occur during writes on multiple
> shards? For example it could easily be the case where a single Update
> statement could effect multiple shards and cause deadlock due to waits
> across the nodes. Now unless we have some distributed lock manager or
> some other way to know the information of locks that happens across
> shards, it could be difficult to detect deadlocks.
>

I wonder if Ashutosh's atomic foreign transactions patch would address any
issues inherent in such cases...

Thanks,
Amit