Notes on Sorted Data

surprisetalk · 2025-12-11T16:52:31.000Z

Discussion: Notes on Sorted Data

Posted29 days agoActive23 days ago

surprisetalk

51 points

7 comments

amit.prasad.meTech Discussionstory

informativeneutral

Debate

0/100

Data StructuresAlgorithmsAI Performance Analysis

Key topics

Data Structures

Algorithms

AI Performance Analysis

Discussion Activity

Moderate engagement

First comment

Peak period

144-156h

Avg / period

Key moments

01Story posted
Dec 11, 2025 at 11:52 AM EST
29 days ago
Step 01
02First comment
Dec 17, 2025 at 12:21 PM EST
6d after posting
Step 02
03Peak activity
7 comments in 144-156h
Hottest window of the conversation
Step 03
04Latest activity
Dec 17, 2025 at 4:43 PM EST
23 days ago
Step 04

Generating AI Summary...

Analyzing up to 500 comments to identify key contributors and discussion patterns

Discussion (7 comments)

Showing 7 comments

Rakshath_1

23 days ago

1 reply

This is a really solid deep-dive. I like how you move from this seems obviouscases (ints, strings) into the subtle edge cases where ordering quietly breaks and then show practical encodings that actually work in byte-lex order. The examples make the pitfalls very concrete, especially the varint and tuple sections. Nice balance between theory and systems-level pragmatism

Sesse__

23 days ago

1 reply

In contrast, I found it rather lacking. No discussion of the most common way to sort floats as bytes (shift the sign bit down and XOR the other 31 bits with the resulting masks), nor NaNs and +/-0 for that matter. Varint sorting introduces its own homegrown serialization but doesn't discuss the issue of overlong encodings. Nothing about string collation or Unicode issues in general. Composite data suggests adding NULs, but what if there are NULs in the actual data? (It is briefly mentioned, but only as in “you can't”.)

amitprasad

23 days ago

1 reply

author here -- agreed on all fronts. Mentioned this in the other comment but I approached the topic from a relatively narrow perspective (I was working on a specific project at the time)

I think it's worth including these things in a future update to the post, but I didn't have the time / need to explore it back then.

In the meantime, I'd point to the following post on Unicode that remains very nice to read >20 years later: https://www.joelonsoftware.com/2003/10/08/the-absolute-minim...

Sesse__

23 days ago

Sure, not all posts want to be the end-all of the topic. :-)

And yes, the Joel post is a good introduction, if a bit old by now. Notably, of course, it doesn't say anything about _processing_ Unicode text. (E.g., don't sort by code point, don't break in the middle of a grapheme cluster, etc. etc.) But I believe that this is outside the scope of his intention.

kristianp

23 days ago

1 reply

I find this approach strange. Surely if you're sorting data, don't do it naively by raw bytes. Use your knowledge of the data type and sort using the appropriate comparison operations of the data type. E.g. sorting by 64 bit ints little endian, do the comparison based on that. If using packed numbers, they must be unpacked first.

amitprasad

23 days ago

Generic data stores often don’t have this luxury — if you’re designing a system in which data is relatively opaque, you’re often forced to work with bytes. (e.g. rocksdb, etc)

amitprasad

23 days ago

Unexpected seeing this posted here.

I wrote this post mostly out of interest for a personal project and thus it's not actually a very holistic exploration of the topic. May revisit and update it in the future :)

View full discussion on Hacker News

ID: 46233794Type: storyLast synced: 12/17/2025, 10:50:29 PM

Want the full context?

Jump to the original sources

Read the primary article or dive into the live Hacker News thread when you're ready.

Open link View on HN