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Subject: Re: how to make query
From: Philip Semanchuk <philip@americanefficient.com>
In-Reply-To: 
 <CALg-PKAjAt7aW3pWcN7BKPtjMiL5v4-cWJOuP_oxOGbhrjLhPQ@mail.gmail.com>
Date: Thu, 7 Jan 2021 12:05:29 -0500
Cc: pgsql-sql@lists.postgresql.org
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Message-Id: <E25CD6BC-D5D2-488C-818C-7C37AE5ABD44@americanefficient.com>
References: 
 <CALg-PKBaGOBtLPD88JLuLkDFh6VarJraupdzOSCKxkAodyRT6w@mail.gmail.com>
 <B554173E-8FCB-480D-8684-8FB60F018B28@americanefficient.com>
 <CALg-PKAjAt7aW3pWcN7BKPtjMiL5v4-cWJOuP_oxOGbhrjLhPQ@mail.gmail.com>
To: Sachin Kumar <sachinkumaras@gmail.com>
Precedence: bulk


> On Jan 7, 2021, at 9:25 AM, Sachin Kumar <sachinkumaras@gmail.com> =
wrote:
>=20
> Hi Philip,
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> I am using Python Django and PostgreSQL to build our report app.
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> I am using below mention query to find some details. the query mention =
below is running fine in PostgreSQL command line and giving result in 2 =
sc for 2 million cards but when i i am try the same in Django =
application it is taking too much of time and the web page is expired =
while running this query.
>=20
> can anyone help how to make query faster in Django? Or help me in =
correcting this query to be used in Django=20


Sachin,
If your query runs well in Postgres, then your problem is with Django, =
not Postgres. You would be better off asking on a Django mailing list =
how to get Django to construct the query you want.


>=20
> On Thu, Jan 7, 2021 at 7:28 PM Philip Semanchuk =
<philip@americanefficient.com> wrote:
>=20
>=20
> > On Jan 7, 2021, at 5:15 AM, Sachin Kumar <sachinkumaras@gmail.com> =
wrote:
> >=20
> > Hi Team,
> >=20
> > we are using Python Django and Postgresql. Our requirement is to =
search 10 Million Card data and bring specific records as a result after =
checking the record every time.
> >=20
> > We have to find data from a 2nd table that is related to the first =
one which we are checking using the loop.
> >=20
> > For Ex:-=20
> > 10000 data - loop 10000 times=20
> > to find data from the 2nd table.=20
> >=20
> > This makes our query too slower and it gets time out.
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> Hi Sachin,
> I=E2=80=99m not sure based on your description, but it sounds like you =
need to tell Django to select related objects all in one query rather =
than one at a time. If that=E2=80=99s the case, then your problem is a =
Django issue, not a Postgres one. Check out select_related() --
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> =
https://docs.djangoproject.com/en/3.1/ref/models/querysets/#django.db.mode=
ls.query.QuerySet.select_related
>=20
>=20
> Cheers
> Philip
>=20
>=20
> --=20
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> Best Regards,=20
> Sachin Kumar