Re: Horizontal scalability/sharding - Mailing list pgsql-hackers

From Amit Langote
Subject Re: Horizontal scalability/sharding
Date
Msg-id 55E6890C.8020302@lab.ntt.co.jp
Whole thread Raw
In response to Re: Horizontal scalability/sharding  (Amit Kapila <amit.kapila16@gmail.com>)
Responses Re: Horizontal scalability/sharding  (Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>)
List pgsql-hackers
On 2015-09-02 PM 01:28, Amit Kapila wrote:
>> On Tue, Sep 1, 2015 at 9:48 PM, Robert Haas <robertmhaas@gmail.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




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