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From: Benedict Holland <[email protected]>
To: Shaozhong SHI <[email protected]>
Cc: Karsten Hilbert <[email protected]>
Cc: Rob Sargent <[email protected]>
Cc: Ron <[email protected]>
Cc: pgsql-general <[email protected]>
Subject: Re: Re: How long does iteration over 4-5 million rows usually take?
Date: Sat, 2 Apr 2022 10:34:34 -0400
Message-ID: <CAD+mzozmywUViFppKBixdD-iTndVDKsDZndq9fvG9=WWOf0x5A@mail.gmail.com> (raw)
In-Reply-To: <CA+i5JwaUOJ+r6H+3VfNaoZXTykAyhpy8q8j5JjHw-=_AWTtLfQ@mail.gmail.com>
References: <[email protected]>
	<[email protected]>
	<trinity-3d817328-9ee8-4c97-a95c-99c034f30558-1648907215445@3c-app-gmx-bap24>
	<CA+i5JwaUOJ+r6H+3VfNaoZXTykAyhpy8q8j5JjHw-=_AWTtLfQ@mail.gmail.com>

For work planning, create a temporary table, copy from a generated data
set, and test it out. It really depends. Normally, you don't iterate in SQL
since rows are assumed to be independent. You think about SQL in terms of
sets and let application code handle the data transfers. It also really
depends on the size of your tables, indexing, joins, and more. Basically,
there isn't really an answer but it isnt hard to test.

Thanks,
Ben


On Sat, Apr 2, 2022, 10:16 AM Shaozhong SHI <[email protected]> wrote:

> Thanks, Karsten,
>
> I would like the information to work planning purpose.
>
> Regards,
>
> David
>
> On Sat, 2 Apr 2022 at 14:47, Karsten Hilbert <[email protected]>
> wrote:
>
>> > > On Apr 1, 2022, at 10:18 PM, Ron <[email protected]> wrote:
>> > >
>> > >  On 4/1/22 20:34, Shaozhong SHI wrote:
>> > >>
>> > >> I have a script running to iterate over 4-5 million rows.  It keeps
>> showing up in red in PgAdmin.  It remains active.
>> > >>
>> > >> How long does iteration over 4-5 million rows usually take?
>> >
>> > 4-5 million times as long as it takes to do one iteration ( if you’re
>> doing it correctly)
>>
>> I may not take quite that long because setup/teardown times might not be
>> needed for each iteration.
>>
>> Best,
>> Karsten
>>
>>
>>

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