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Data engineering

Trouble with Polars performance

2 posts from 2 people2d activeSteady, +1 this weekunverified

Posts per day

Posts per day2 posts, Oct 9 to Nov 13

The posts behind it

GitHub issuespola-rs/polars · moamen-devNov 7

An enhanecment that boosts Polars's performance by 15-30%!!

### Description Hey.... I've discovered that Polars don't cache columns operations... like: here... trade_value will get computed not only once, but instead every call!!! but here: this version is much faster "15% - 30% !!" and uses much less memory.... I've wrote a script to do...

1 reactions
GitHub issuespola-rs/polars · fsimkovicOct 9

Performance discrepancy for `df.filter(...)`

### 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 It appears that there is a...

1 reactions1 replies

Companies and products named

2 posts
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About this problem

Evidence

2 posts from 2 people in 1 place, about 1 a week over 30 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 "performance". First post Oct 9, 2026, latest Nov 7, 2026. Unverified: fewer than 3 posts, or one person or place only. Method

Other Polars problems

Trouble with Polars group

Top post: "Datetime out-of-range in `group_by_dynamic` streaming engine", one of 10 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 8 posts from 8 people on GitHub issues.

Polars upgrades break working setups

24 posts from 17 people on GitHub issues.

Trouble with Polars column

Top post: "Compare lists in one column to the first n elements of another column in Python Polars lazyframes, where n is", one of 21 posts from 16 people on GitHub issues, Stack Overflow.

Polars users keep filing bugs

Top post: "Consider upgrading the brotli crate (CVE-2026-111497)", one of 20 posts from 14 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 cache

Top post: "Predicate pushdown into a shared cache applies a filter below each branch's slice", one of 5 posts from 4 people on GitHub issues.

Trouble with Polars streaming

Top post: "`min_by`/`max_by`/`sort_by` with a scalar `by`: in-memory engine raises, streaming broadcasts", one of 5 posts from 3 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 5 posts from 5 people on GitHub issues.

Trouble with Polars iceberg

Top post: "`sink_iceberg` ignores catalog credentials", one of 5 posts from 3 people on GitHub issues.

Bad data slips through Polars unnoticed

4 posts from 4 people on GitHub issues, Reddit.

Trouble with Polars value

Top post: "polars.read_excel() value error on very large date", one of 4 posts from 4 people on GitHub issues.

History

First seen with 2 posts; the top post now: "Performance discrepancy for `df.filter(...)`".

Nov 12, 2026