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help / color / mirror / Atom feedFrom: Adrian Klaver <[email protected]>
To: Pecsök Ján <[email protected]>
To: [email protected] <[email protected]>
Subject: Re: Reading execution plan - first row time vs last row time
Date: Tue, 1 Oct 2024 07:15:47 -0700
Message-ID: <[email protected]> (raw)
In-Reply-To: <AS1PR05MB91059DA7056B7C30EAE61AA59F772@AS1PR05MB9105.eurprd05.prod.outlook.com>
References: <AS1PR05MB91059DA7056B7C30EAE61AA59F772@AS1PR05MB9105.eurprd05.prod.outlook.com>
On 10/1/24 06:53, Pecsök Ján wrote:
> Dear community,
>
> We see significant difference in explain analyze Actual time in the
> first line of execution plan and Execution time in the last line of
> execution plan. What can be the reason?
>
> For example, first line of execution plan:
>
> Gather (cost=1038.49..257627100.42 rows=7943222226 width=104) (actual
> time=531.925..3673159.806 rows=7943221053 loops=1)
>
> This is 3673159/1000/60 = 61 minutes
>
> And last 2 lines of execution plan:
>
> Planning Time: 3000.399 ms
>
> Execution Time: 21208130.602 ms
>
> This is : 21208130/1000/60= 353 minutes
>
> What happened in 353 – 61 = 292 minutes? We speculate that disk writes.
> Query possibly written cca 0,75TB of data, by create table as select query.
You will need to show the complete EXPLAIN ANALYZE output as well as query.
>
>
> S pozdravem
>
> *Ján Pecsők*
>
> Tychonova 2, 160 00 Praha
> Mobil: +420 775 942 871
> [email protected] <mailto:[email protected]>
> www.profinit.eu <https://www.profinit.eu/;
>
> <https://www.profinit.eu/;
>
--
Adrian Klaver
[email protected]
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