Re: [Postgres-xc-general] Looks like co-ordinator is my perf bottleneck....somebody help...

[Mason S. <ms...@tr...>]

On Sat, Feb 1, 2014 at 2:13 PM, Nirmal Sharma <sha...@gm...>wrote:

> My query uses aggregates and joins and it looks like this :
>
> Select
> Sum(...),
> Sum(..),
> Avg(..),
> ...
> ....
> ..
> From tableA a inner join tableB on a.col1 =b.col1
>                         Inner join tableC on a.col1=c.col1
>
> All the 3 tables are distributed  on hash(col1) .
>
> I have 1 coordinator , 6 nodes, 1 GTM.
>
> When I run this query , it takes total 23 sec.
> But when I run the same query on each and individual nodes then it takes 4
> sec on each and every nodes.
> So since it's cluster , it should ideally take 4 sec + some overhead time
> to combine data from each node on coordinator ( max 2 more sec) but I don't
> understand why it is taking 23 sec when runs from coordinator.
>


Can you please add an EXPLAIN in from of your SELECT to look at the plan?
If you only use 2 tables instead of 3, does it behave more as expected?