Data and AI struggles

1,483 problems · 320 companies

Data engineering

Trouble with Polars slice

2 posts from 2 people2d activeFading, +0 this weekunverified

Posts per day

Posts per day2 posts, Sep 6 to Nov 2

The posts behind it

GitHub issuespola-rs/polars · HunterligeOct 14

Predicate pushdown into a shared cache applies a filter below each branch's slice

### Checks - [x] I have checked that this issue has not already been reported. - [x] I have confirmed this bug exists on the [latest version](https://pypi.org/project/polars/) of Polars. ### Reproducible example ### Log output ### Issue description The filtered result is empty...

1 reactions1 replies
GitHub issuespola-rs/polars · adienesSep 6

`Series.slice` function behaves incorrectly (vs `slice` as an expression)

### Checks - [x] I have checked that this issue has not already been reported. - [x] I have confirmed this bug exists on the [latest version](https://pypi.org/project/polars/) of Polars. ### Reproducible example ### Log output ### Issue description the `series.slice(-5)` call...

1 reactions

Companies and products named

2 posts
2 posts
About this problem

Evidence

2 posts from 2 people in 1 place, about 1 a week over 39 days. Mostly on pola-rs/polars. Tools named alongside: PyPI.

Frustration Frustration 0 of 3· Seen on GitHub issues

How it was grouped

Posts about Polars with no known issue, sharing the word "slice". First post Sep 6, 2026, latest Oct 14, 2026. Unverified: fewer than 3 posts, or one person or place only. Method

Other Polars problems

Trouble with Polars column

Top post: "Lazy join returns wrong data when a suffixed column (id_right) has the same name as the right join key", one of 17 posts from 13 people on GitHub issues.

Trouble with Polars unique

Top post: "Streaming engine: multi-column `.unique()` in `group_by().agg()` much slower than in-memory", one of 7 posts from 4 people on GitHub issues.

Trouble with Polars returns

Top post: "GPU `max_horizontal` returns NaN for a finite value followed by NaN", one of 3 posts from 2 people on GitHub issues.

Polars users keep filing bugs

Top post: "Consider upgrading the brotli crate (CVE-2026-111497)", one of 22 posts from 15 people on GitHub issues.

Trouble with Polars group

Top post: "Datetime out-of-range in `group_by_dynamic` streaming engine", one of 4 posts from 3 people on GitHub issues.

Polars upgrades break working setups

23 posts from 16 people on GitHub issues.

Trouble with Polars parquet

Top post: "`is_in` with more than 100 values does not skip Parquet row groups between the values", one of 7 posts from 7 people on GitHub issues.

Trouble with Polars join

Top post: "Coalescing full join on Int32-vs-Int64 keys with `unique` incorrect", one of 6 posts from 6 people on GitHub issues.

Trouble with Polars instead

Top post: "Series.to_list() panics on out-of-range datetimes instead of raising an error", one of 6 posts from 6 people on GitHub issues.

Bad data slips through Polars unnoticed

3 posts from 3 people on GitHub issues, Reddit.

Polars runs out of memory

3 posts from 3 people on GitHub issues.

Trouble with Polars read

Top post: "`read_database` raises `ImportError` with SQLAlchemy 2.1 when `greenlet` is not installed", one of 3 posts from 3 people on GitHub issues.

History

First seen with 1 post; the top post now: "Predicate pushdown into a shared cache applies a filter below each branch's slice".

Oct 24, 2026