Re: Binary transfer vs Text transfer

From: Aleksei Ivanov <iv(dot)alekseii(at)gmail(dot)com>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Binary transfer vs Text transfer
Date: 2020-06-18 05:19:29
Message-ID: CAN0E21MzMtoxPtoZfsss0UBV_DsoRZ=5SX4cU8uj8y6U6A=M6A@mail.gmail.com
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Hi,

Thanks for the attached link, but I also noticed using iftop, that during
fetching the data there is almost no delay using text transfer, while there
is several seconds in delay before data is starting fetching using binary
transfer. Could you suggest where can I have a look to resolve it or
decrease that time?

Best regards,

On Wed, Jun 17, 2020 at 12:12 Andres Freund <andres(at)anarazel(dot)de> wrote:

> Hi,
>
>
> On 2020-06-17 11:55:44 -0700, Aleksei Ivanov wrote:
> > I have one question related to my current measurements results.
> >
> > I am fetching integers in text format like:
> >
> > Select * from table limit 10000000. It take 18.5 seconds to finish and
> the
> > transfer data is 633 MB.
> >
> > When I fetching the same data using binary cursor, the transfer data is
> 480
> > MB, but the transfer time is 21.5 seconds?
> >
> > So, I have one question could someone explain what can be the reason why
> > the transferring time for binary data is higher?
>
> This thread might be interesting:
>
> https://www.postgresql.org/message-id/CAMkU%3D1whbRDUwa4eayD9%2B59K-coxO9senDkPRbTn3cg0pUz4AQ%40mail.gmail.com
>
> Greetings,
>
> Andres Freund
>

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