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Re: Removing a key from jsonb is sloooow - Mailing list pgsql-general

From Volkan Unsal
Subject Re: Removing a key from jsonb is sloooow
Date
Msg-id CAMcqKm=3f2cM1VCvSaU-vNz+SfMBDK7zR=V-xg06Ja6UwGgaOw@mail.gmail.com
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In response to Re: Removing a key from jsonb is sloooow  (Adrian Klaver <adrian.klaver@aklaver.com>)
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More information about my setup:

Postgres version:
PostgreSQL 10.9 (Debian 10.9-1.pgdg90+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 6.3.0-18+deb9u1) 6.3.0 20170516, 64-bit

Table schema:
CREATE TABLE public.projects (
   misc jsonb DEFAULT '{}'::jsonb NOT NULL
);

Explain analyze:
explain analyze update projects set misc = misc - 'foo';

Update on projects  (cost=0.00..4240.93 rows=10314 width=1149) (actual time=346318.291..346318.295 rows=0 loops=1)     
  ->  Seq Scan on projects  (cost=0.00..4240.93 rows=10314 width=1149) (actual time=1.011..266.435 rows=10314 loops=1) 
Planning time: 40.087 ms                                                                                               
Trigger trigger_populate_tsv_body_on_projects: time=341202.492 calls=10314                                             
Execution time: 346320.260 ms                                                                                          

Time: 345969.035 ms (05:45.969)


Figured out that it's due to the trigger. Thanks for your help, Adrian!


On Wed, Jul 17, 2019 at 10:39 AM Adrian Klaver <adrian.klaver@aklaver.com> wrote:
On 7/17/19 7:30 AM, Volkan Unsal wrote:
> I'm trying to remove a key from a jsonb column in a table with 10K rows,
> and the performance is abysmal. When the key is missing, it takes 5
> minutes. When the key is present, it takes even longer.
>
> Test with non-existent key:
>
>  >> update projects set misc = misc - 'foo';
> Time: 324711.960 ms (05:24.712)
>
> What can I do to improve this?

Provide some useful information:

1) Postgres version

2) Table schema

3) Explain analyze of query



--
Adrian Klaver
adrian.klaver@aklaver.com


--
Volkan Unsal
Product Engineer

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