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From Jörn Franke <jornfra...@gmail.com>
Subject Re: [SparkSQL] SparkSQL performance on small TPCDS tables is very low when compared to Drill or Presto
Date Thu, 29 Mar 2018 05:33:20 GMT
I don’t think select * is a good benchmark. You should do a more complex operation, otherwise
optimizes might see that you don’t do anything in the query and immediately return (similarly
count might immediately return by using some statistics).

> On 29. Mar 2018, at 02:03, Tin Vu <tvu032@ucr.edu> wrote:
> 
> Hi,
> 
> I am executing a benchmark to compare performance of SparkSQL, Apache Drill and Presto.
My experimental setup:
> TPCDS dataset with scale factor 100 (size 100GB).
> Spark, Drill, Presto have a same number of workers: 12.
> Each worked has same allocated amount of memory: 4GB.
> Data is stored by Hive with ORC format.
> I executed a very simple SQL query: "SELECT * from table_name"
> The issue is that for some small size tables (even table with few dozen of records),
SparkSQL still required about 7-8 seconds to finish, while Drill and Presto only needed less
than 1 second.
> For other large tables with billions records, SparkSQL performance was reasonable when
it required 20-30 seconds to scan the whole table.
> Do you have any idea or reasonable explanation for this issue?
> Thanks,
> 

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