Re: [Postgres-xc-general] Performance difference between postgress and postgres-XC

[Ashutosh B. <ash...@en...>]

On Tue, Feb 25, 2014 at 11:20 PM, Nirmal Sharma <sha...@gm...>wrote:

> Hi All,
>
> Thanks for your reply.
>
> So now i have 2 questions:
>
> 1.  I have this machine  (Mem: 32 GB and Cores:16) and  have these 2
> option -> (a) Install postgress on the same and start using it. (b) Create
> a 3 node PG-XC cluster on the same machine and start using it.
> So can you tell me which option is better ? Does it make sense to create a
> cluster on the same machine or is it always better to use separate physical
> machines for each node to create an PG-XC cluster?
>

You should never deploy all your nodes on the same machine, that will just
deteriorate the performance.


>
> 2. What is the better configuration for PG-XC cluster among these ->
>     (a) For 3 Node cluster, having 1 coordinator and 3 data node is better
> than having 1 separate coordinator for each data node (i.e 3 Cord, 3 data
> node)?
>
>
It depends upon the work load. If the work load is such that the
coordinators are loaded and datanodes not, then you need to add more
coordinators. An example is large number of connections. So, you will need
to monitor your cluster, to see whether the coordinators are loaded.


>
> Please reply.
>
> Regards.
>
>
>
> On Mon, Feb 24, 2014 at 10:31 PM, Ashutosh Bapat <
> ash...@en...> wrote:
>
>>
>>
>>
>> On Tue, Feb 25, 2014 at 4:47 AM, Nirmal Sharma <sha...@gm...>wrote:
>>
>>> *This is my postgres box config:*
>>>   Mem             : 32GB  Cores           : 16  model name      :
>>> Intel(R) Xeon(R) CPU           E5630  @ 2.53GHz  stepping        : 2  cpu
>>> MHz         : 2527.184  cache size      : 12288 KB
>>> *This is my pg-xc (1 cordinator and 3 data node cluster) config:*
>>>
>>> (All the 4 physical boxes are same with below mentioned config)
>>>  Mem             : 24GB  Cores:            8  Model name:    stepping
>>> : 5  cpu MHz         : 1994.961  cache size      : 4096 KB
>>>
>>>
>> For an apple to apple comparison, it's better to have Postgres and each
>> of the coordinator/datanode of XC deployed on same kind of configuration.
>> From the description, it looks like single Postgres is getting better
>> hardware. So, it's not surprising to see XC not getting at-par performance
>> when compared to PG.
>>
>>>
>>>
>>>  In Pg-xc, only my dimension tables are replicated and facts are hash
>>> key distributed. Data and other things are same in pg and pg-xc.
>>> My pg-xc is giving me only marginal better performance than pg and thats
>>> the reason i am wondering whether to use pg-xc or not?
>>>
>>>
>> This distribution looks good. Make sure that you are using the right keys
>> for distributed tables. Please check my presentation at
>> http://www.youtube.com/watch?v=T1OPKvyj87Q. That might give some more
>> hints as to how to choose right distribution strategy.
>>
>>
>>> Regards
>>> ~Nirmal
>>>
>>>
>>> On Mon, Feb 24, 2014 at 3:09 PM, Mason Sharp <ms...@tr...>wrote:
>>>
>>>>
>>>>
>>>>
>>>> On Mon, Feb 24, 2014 at 2:11 PM, Nirmal Sharma <sha...@gm...
>>>> > wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I am using both postgress and postgress-XC and both are working fine
>>>>> but in terms of performance, they both are same(with same amount of data in
>>>>> both).
>>>>> I was hoping for better performance in pg-xc but it is just marginally
>>>>> better than PG and not much. So why then to use pg-xc?
>>>>>
>>>>> Can somebody tell me in what cases do we use pg-xc rather than PG?
>>>>>
>>>>>
>>>> It all depends on your workload and configuration. How many nodes and
>>>> physical servers are you using, and what is your workload and schema like?
>>>> Hopefully you are not replicating every table.
>>>>
>>>> There are cases like TPC-C where you will experience a noticeable
>>>> improvement.  There are other cases like TPC-H where performance will be
>>>> worse than plain  PostgreSQL.
>>>>
>>>>
>>>> --
>>>> Mason Sharp
>>>>
>>>> TransLattice - http://www.translattice.com
>>>> Distributed and Clustered Database Solutions
>>>>
>>>>
>>>>
>>>
>>>
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>>>
>>
>>
>> --
>> Best Wishes,
>> Ashutosh Bapat
>> EnterpriseDB Corporation
>> The Postgres Database Company
>>
>
>


-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company