| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
| Cc: | Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>, John Gorman <johngorman2(at)gmail(dot)com>, Stephen Frost <sfrost(at)snowman(dot)net>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Parallel Seq Scan |
| Date: | 2015-01-22 14:17:00 |
| Message-ID: | CA+TgmobKaYREemD-iyGpgUeEajJ5fsoGejuYk0CgE9LXTWy79A@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Thu, Jan 22, 2015 at 9:02 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)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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