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From: Deepak Goel <deicool@gmail.com>
Date: Tue, 5 Aug 2025 10:51:22 +0530
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 <CA+b7NVXqrV8b6O=6OkSNLS97BuD2L1orss_D8hPL2ta_PiMpoQ@mail.gmail.com>
Subject: Re: DB load balancer
To: Siraj G <tosiraj.g@gmail.com>
Cc: Pgsql-admin <pgsql-admin@lists.postgresql.org>
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Please share what you mean by slow (CPU usage of secondary over time,
response times of the transactions over time).


Deepak
"The greatness of a nation can be judged by the way its animals are treated
- Mahatma Gandhi"

+91 73500 12833
deicool@gmail.com

LinkedIn: www.linkedin.com/in/deicool

"Plant a Tree, Go Green"

Make In India : http://www.makeinindia.com/home


On Tue, Aug 5, 2025 at 10:18=E2=80=AFAM Siraj G <tosiraj.g@gmail.com> wrote=
:

> Hello Experts!
>
> We have a multi tenant model DB with a Primary and a Secondary. There are
> 3x or 4x connections flowing to Secondary as the application is read
> intensive. Accordingly we have allocated more number of resources to the =
VM
> hosting the secondary/replica DB.
>
> Spec:-
> Primary: 48 CPUs, 48GB memory
> Secondary: 80 CPUs, 128GB memory
> PG version: 12.22 (we have already started the upgrade process)
> OS: Ubuntu
>
> The problem very frequently we are experiencing is that the CPU load on
> the SECONDARY is going very very high causing the app slowness. Also,
> frequently the postgres is crashing due to OOM.
>
> I was thinking of these (please give feedback):
> 1. Have a DB level balancer for the load balancing in the DB level,
> meaning primary will also receive the READ traffic
> 2. Add a second REPLICA and configure load balancer for the connection
> load balancing
>
> What do we do for load balancing at the DB level, in postgres?
>
> If there are any suggestions, please let me know.
>
> Regards
> Siraj
>

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<div dir=3D"ltr"><div>Please share what you mean by slow (CPU usage of seco=
ndary over time, response times of the transactions=C2=A0over time).</div><=
div><div dir=3D"ltr" class=3D"gmail_signature" data-smartmail=3D"gmail_sign=
ature"><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"><div><d=
iv dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D=
"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"><di=
v><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div di=
r=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"><div><div dir=3D"ltr"=
><div><font size=3D"2"><br></font><div dir=3D"ltr"><font size=3D"2"><br>Dee=
pak<br></font></div><div><font size=3D"2">&quot;<span style=3D"font-family:=
Arial;color:rgb(34,34,34);background-color:rgb(255,255,255);font-weight:400=
;font-style:normal;font-variant:normal;text-decoration:none;vertical-align:=
baseline;white-space:pre-wrap">The greatness of a nation can be judged by t=
he way its animals are treated - Mahatma Gandhi</span>&quot;<br><br></font>=
</div><div dir=3D"ltr"><font size=3D"2">+91 73500 12833<br><a href=3D"mailt=
o:deicool@gmail.com" target=3D"_blank">deicool@gmail.com</a><br><br><span>L=
inkedIn:=C2=A0</span><a href=3D"http://www.linkedin.com/in/deicool" target=
=3D"_blank">www.linkedin.com/in/deicool</a></font></div></div><div dir=3D"l=
tr"><br></div><div><font size=3D"2">&quot;Plant a Tree, Go Green&quot;</fon=
t></div><div><font size=3D"2"><br></font></div><div><font size=3D"2">Make I=
n India : <a href=3D"http://www.makeinindia.com/home" target=3D"_blank">htt=
p://www.makeinindia.com/home</a><br></font></div></div></div></div></div></=
div></div></div></div></div></div></div></div></div></div></div></div></div=
></div></div></div></div></div></div></div></div></div></div></div></div></=
div></div></div></div></div></div><br></div><br><div class=3D"gmail_quote g=
mail_quote_container"><div dir=3D"ltr" class=3D"gmail_attr">On Tue, Aug 5, =
2025 at 10:18=E2=80=AFAM Siraj G &lt;<a href=3D"mailto:tosiraj.g@gmail.com"=
>tosiraj.g@gmail.com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quo=
te" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204=
);padding-left:1ex"><div dir=3D"ltr">Hello Experts!<div><br></div><div>We h=
ave a multi tenant model DB with a Primary and a Secondary. There are 3x or=
 4x connections flowing to Secondary as the application is read intensive. =
Accordingly we have allocated more number of resources to the VM hosting th=
e secondary/replica DB.=C2=A0</div><div><br></div><div>Spec:-=C2=A0</div><d=
iv>Primary: 48 CPUs, 48GB memory</div><div>Secondary: 80 CPUs, 128GB memory=
</div><div>PG version: 12.22 (we have already started the upgrade process)<=
/div><div>OS: Ubuntu</div><div><br></div><div>The problem very frequently w=
e are experiencing is that the CPU load on the SECONDARY is going very very=
 high causing the app slowness. Also, frequently the postgres is crashing d=
ue to OOM.</div><div><br></div><div>I was thinking of these (please give fe=
edback):</div><div>1. Have a DB level balancer for the load balancing in th=
e DB level, meaning primary will also receive the READ traffic</div><div>2.=
 Add a second REPLICA and configure load balancer for the connection load b=
alancing</div><div><br></div><div>What do we do for load balancing at the D=
B level, in postgres?</div><div><br></div><div>If there are any suggestions=
, please=C2=A0let me know.</div><div><br></div><div>Regards</div><div>Siraj=
</div></div>
</blockquote></div>

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