Using show() after DISTINCT on INTs causes query to hang in Python

[andre214]

What happens?

I wanted to get some unique values from a table in Python but it seems that when I try to .show() the result, something causes it to freeze.

Here's the research I've conducted so far:

• I can .show() the same query without using DISTINCT and it displays the result instantly
• I can also use .fetchall() and DISTINCT and it works instantly
• It seems the number of duplicates seems to affect whether this happens. In a table with around 16000 unique values all repeated 5 times, the bug occurs but when the IDs are all unique it doesn't
• If the values are doubles rather than ints, the bug doesn't occur

To Reproduce

The subquery is just to generate a table with INTs 0 to 16000 all repeated 5 times.

import duckdb
duckdb.sql("""
  SELECT DISTINCT y FROM (
      SELECT cast(floor(generate_series/5) AS INT) AS y FROM generate_series(16000*5)
)
""").show()

OS:

Windows 10 x64

DuckDB Version:

0.9.3.dev42

DuckDB Client:

Python

Full Name:

andre214

Affiliation:

personal

Have you tried this on the latest main branch?

I have tested with a main build

Have you tried the steps to reproduce? Do they include all relevant data and configuration? Does the issue you report still appear there?

• Yes, I have

[szarnyasg]

This indeed hangs on the current dev version.

[Tishj]

I think this has been fixed by #10503 or #10318

On the latest dev version it doesn't hang anymore.