Re: Parallel Seq Scan - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Parallel Seq Scan
Date
Msg-id CA+TgmobKaYREemD-iyGpgUeEajJ5fsoGejuYk0CgE9LXTWy79A@mail.gmail.com
Whole thread Raw
In response to Re: Parallel Seq Scan  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-hackers
On Thu, Jan 22, 2015 at 9:02 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>> I'm confused.  Your actual test numbers seem to show that the
>> performance with the block-by-block approach was slightly higher with
>> parallelism than without, where as the performance with the
>> chunk-by-chunk approach was lower with parallelism than without, but
>> the text quoted above, summarizing those numbers, says the opposite.
>
> Sorry for causing confusion, I should have been more explicit about
> explaining the numbers.  Let me try again,
> Values in columns is time in milliseconds to complete the execution,
> so higher means it took more time.  If you see in block-by-block, the
> time taken to complete the execution with 2 workers is more than
> no workers which means parallelism has degraded the performance.

*facepalm*

Oh, yeah, right.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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