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From: atma ram <atmaramkp@gmail.com>
Date: Wed, 26 Nov 2025 18:50:41 +0530
Message-ID: <CAA1Yw9-rOunXTb8DEPCZKkEts1gj3oThKidCSVn6egVe9W4-UQ@mail.gmail.com>
Subject: =?UTF-8?Q?Question_on_PostgreSQL_Table_Partitioning_=E2=80=93_Perfor?=
	=?UTF-8?Q?mance_of_Queries_That_Do_Not_Use_the_Partition_Key?=
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Hi,

Question on PostgreSQL Table Partitioning =E2=80=93 Performance of Queries =
That Do
Not Use the Partition Key

We have a table that is approximately 1.6 GB in size. Query performance has
started to degrade. Although we have multiple indexes, the large table size
is still causing performance issues.

We are planning to partition the table on the primary key. This is an OLTP
system, and there are around 100 queries that access this table. About 80
of these queries use the primary key and will therefore benefit directly
from the partition key once we implement partitioning. However, the
remaining 20 queries do not use the primary key; they rely on other indexed
columns.

Our question is: after partitioning the table, and after creating the
necessary indexes on each partition, what happens to the performance of
those 20 queries that do *not* use the partition key?
=E2=80=93 Will their performance degrade?
=E2=80=93 Will it remain the same as before partitioning?
=E2=80=93 Is there any chance it will improve?

Additional details: we plan to create only 16 partitions, so the partition
count will not be very high.

*Is there any benchmarking, documentation, or reference material that can
help demonstrate how partitioning will affect the performance of the 20
queries that do not use the partition key?*

This information is critical for us before proceeding with the partitioning
strategy.

Thank you in advance.

Regards,
Atma

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<div dir=3D"ltr">Hi,<div><br></div><div><div>Question on PostgreSQL Table P=
artitioning =E2=80=93 Performance of Queries That Do Not Use the Partition =
Key=C2=A0=C2=A0</div><div><br></div><div><p>We have a table that is approxi=
mately 1.6 GB in size. Query performance has started to degrade. Although w=
e have multiple indexes, the large table size is still causing performance =
issues.</p>
<p>We are planning to partition the table on the primary key. This is an OL=
TP system, and there are around 100 queries that access this table. About 8=
0 of these queries use the primary key and will therefore benefit directly =
from the partition key once we implement partitioning. However, the remaini=
ng 20 queries do not use the primary key; they rely on other indexed column=
s.</p>
<p>Our question is: after partitioning the table, and after creating the ne=
cessary indexes on each partition, what happens to the performance of those=
 20 queries that do <strong>not</strong> use the partition key?<br>
=E2=80=93 Will their performance degrade?<br>
=E2=80=93 Will it remain the same as before partitioning?<br>
=E2=80=93 Is there any chance it will improve?</p>
<p>Additional details: we plan to create only 16 partitions, so the partiti=
on count will not be very high.</p><p><strong>Is there any benchmarking, do=
cumentation, or reference material that can help demonstrate how partitioni=
ng will affect the performance of the 20 queries that do not use the partit=
ion key?</strong></p><div class=3D"gmail-text-base gmail-my-auto gmail-mx-a=
uto gmail-pb-10 gmail-[--thread-content-margin:--spacing(4)] gmail-thread-s=
m:[--thread-content-margin:--spacing(6)] gmail-thread-lg:[--thread-content-=
margin:--spacing(16)] gmail-px-(--thread-content-margin)"><div class=3D"gma=
il-[--thread-content-max-width:40rem] gmail-thread-lg:[--thread-content-max=
-width:48rem] gmail-mx-auto gmail-max-w-(--thread-content-max-width) gmail-=
flex-1 gmail-group/turn-messages gmail-focus-visible:outline-hidden gmail-r=
elative gmail-flex gmail-w-full gmail-min-w-0 gmail-flex-col gmail-agent-tu=
rn" tabindex=3D"-1"><div class=3D"gmail-z-0 gmail-flex gmail-min-h-[46px] g=
mail-justify-start"></div><div class=3D"gmail-mt-3 gmail-w-full empty:hidde=
n"><div class=3D"gmail-text-center"></div></div></div></div>
<p>This information is critical for us before proceeding with the partition=
ing strategy.</p></div><div><br></div><div>Thank you in advance.</div><div>=
<br></div><div>Regards,</div><div>Atma</div><div><br><br></div><div><br></d=
iv></div></div>

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