RE: Parallel INSERT (INTO ... SELECT ...)

From: "Tang, Haiying" <tanghy(dot)fnst(at)cn(dot)fujitsu(dot)com>
To: Greg Nancarrow <gregn4422(at)gmail(dot)com>
Cc: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Antonin Houska <ah(at)cybertec(dot)at>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, vignesh C <vignesh21(at)gmail(dot)com>, "Bharath Rupireddy" <bharath(dot)rupireddyforpostgres(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, "Tsunakawa, Takayuki" <tsunakawa(dot)takay(at)fujitsu(dot)com>, "Hou, Zhijie" <houzj(dot)fnst(at)cn(dot)fujitsu(dot)com>
Subject: RE: Parallel INSERT (INTO ... SELECT ...)
Date: 2021-02-08 08:12:40
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

> Did it actually use a parallel plan in your testing?
> When I ran these tests with the Parallel INSERT patch applied, it did
> not naturally choose a parallel plan for any of these cases.

Yes, these cases pick parallel plan naturally on my test environment.

postgres=# explain verbose insert into testscan select a from x where a<80000 or (a%2=0 and a>199900000);
Gather (cost=4346.89..1281204.64 rows=81372 width=0)
Workers Planned: 4
-> Insert on public.testscan (cost=3346.89..1272067.44 rows=0 width=0)
-> Parallel Bitmap Heap Scan on public.x1 (cost=3346.89..1272067.44 rows=20343 width=8)
Output: x1.a, NULL::integer
Recheck Cond: ((x1.a < 80000) OR (x1.a > 199900000))
Filter: ((x1.a < 80000) OR (((x1.a % 2) = 0) AND (x1.a > 199900000)))
-> BitmapOr (cost=3346.89..3346.89 rows=178808 width=0)
-> Bitmap Index Scan on x1_a_idx (cost=0.00..1495.19 rows=80883 width=0)
Index Cond: (x1.a < 80000)
-> Bitmap Index Scan on x1_a_idx (cost=0.00..1811.01 rows=97925 width=0)
Index Cond: (x1.a > 199900000)

PSA is my postgresql.conf file, maybe you can have a look. Besides, I didn't do any parameters tuning in my test session.


Attachment Content-Type Size
postgresql.conf application/octet-stream 27.5 KB

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Markus Wanner 2021-02-08 08:31:12 repeated decoding of prepared transactions
Previous Message Andy Fan 2021-02-08 08:04:46 Re: cost_sort vs cost_agg