Re: Parallell Optimizer

> On 11 June 2013 01:45, Tatsuo Ishii <ishii@postgresql.org> wrote:
>>> On Sat, Jun 8, 2013 at 5:04 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
>>>
>>>> On 7 June 2013 20:23, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>>>>
>>>> > As for other databases, I suspect that ones that have parallel execution
>>>> > are probably doing it with a thread model not a process model.
>>>>
>>>> Separate processes are more common because it covers the general case
>>>> where query execution is spread across multiple nodes. Threads don't
>>>> work across nodes and parallel queries predate (working) threading
>>>> models.
>>>>
>>> Indeed. Parallelism based on processes would be more convenient for
>>> master-master
>>> type of applications. Even if no master-master feature is implemented
>>> directly in core,
>>>  at least a parallelism infrastructure based on processes could be used for
>>> this purpose.
>>
>> As long as "true" synchronous replication is not implemented in core,
>> I am not sure there's a value for parallel execution spreading across
>> multile nodes because of the delay of data update propagation.
> 
> Please explain what you mean by the word "true" used here.

In another word, "eager replication".
--
Tatsuo Ishii
SRA OSS, Inc. Japan
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