Going Down the Rabbit Hole of Postgres 18 Features

Posted3 months agoActive3 months ago

tudorg

56 points

5 comments

xata.ioTechstory

calmpositive

Debate

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PostgresDatabaseSQLPerformance Optimization

Key topics

Postgres

Database

SQL

Performance Optimization

The article explores new features in Postgres 18, sparking a discussion on the nuances of certain features, such as redundant GROUP BY columns with UNIQUE indexes.

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01Story posted
Sep 29, 2025 at 6:09 PM EDT
3 months ago
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02First comment
Sep 30, 2025 at 1:03 AM EDT
7h after posting
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1 comments in 6-8h
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04Latest activity
Oct 1, 2025 at 2:21 AM EDT
3 months ago
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Discussion (5 comments)

Showing 5 comments

rixed

3 months ago

1 reply

Interesting and comprehensive article.

Note to the author : on mobile, none of the examples are visible.

sierra1011

3 months ago

1 reply

Works for me on Brave, Android 15.

rixed

3 months ago

1 reply

I was using Firefox on IOS.

tudorgAuthor

3 months ago

Thanks for the report!

tpxl

3 months ago

I think the author may have misunderstood the redundant GROUP BY columns with UNIQUE indexes. If you group by columns (A, B, C) and there is a UNIQUE index on (A, B), you can remove C (all parts not in the unique key), as there will only ever be at most one value of C due to the unique key constraint.

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ID: 45419412Type: storyLast synced: 11/20/2025, 3:47:06 PM

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