Problemsby GlyphPolars users keep filing bugs
22 posts from 15 people13d activeFading, +0 this week
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The posts behind it
GPU engine rejects `min_horizontal` on String expressions
### 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 Computing...
GPU engine rejects `str.encode("hex")` with a HexEncode diagnostic
### 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 Applying `str.encode("hex")`...
GPU engine rejects a formatted per-row duration passed to `dt.offset_by`
### 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 query builds an...
GPU Int64 `pow(2)` loses precision for `100000001`
### 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 Squaring the Int64 value...
Consider upgrading the brotli crate (CVE-2026-111497)
### Description ## Summary This is an early, precautionary suggestion, not a report of a confirmed vulnerability in Polars. I haven’t found evidence that Polars is affected. I’m opening this so the maintainers are aware of the issue and can check the Brotli dependency. ##...
Inaccurate description for `serde-lazy` feature
### Description In `docs/source/user-guide/installation.md` and `crates/polars/src/lib.rs`, the description of the `serde-lazy` feature is a word-for-word copy of the `serde` description: This doesn't say what `serde-lazy` adds. Looking at the feature definitions: -...
when/then can throw a PanicException since 1.44
...2.0.0 This could be related to https://github.com/pola-rs/polars/issues/28932 This is a workaround: ### Expected behavior I expect no exeception to be thrown. I also expected the code not to run for the empty cell, because of the when/then clause. ### Installed versions
Support EXISTS subqueries in JOINs (SQL)
### Description Continuing with [SQLStorm exploration](https://github.com/pola-rs/polars/issues/30120), 4 of the first 300 queries fail due to JOINs not supporting an EXISTS subquery.
str.replace / str.replace_all don't expand $ in the replacement when the pattern has no punctuation
...Add any punctuation ("USD|EUR") and it's expanded like the docs describe. This makes $ unreliable when the pattern isn't known ahead of time, e.g. built from a variable. Looks like this comes from `is_literal_pat` in polars-expr/src/dispatch/strings.rs: patterns without...
SQL: unknown or alias-hidden names are accepted in correlated subquery
### 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 In a correlated subquery, a...
Cannot compile polars using rust 1.99.1
### 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://crates.io/crates/polars) of Polars. ### Reproducible example I updated my Rust toolchain to current stable (1.99.1) and went to...
SQL: a table name that matches several tables ignoring case picks one at random
...of ambiguous table names with unpredictable outcome. ### Expected behavior Expected: an error when table names can cause ambiguity or cannot be resolved. ### Installed versions Reproduces on 2.0 and latest main.
Memory budget ignores the memory limit of a nested cgroup (e.g. SLURM, systemd)
.../cgroup` and takes the smallest limit of the process cgroup and all its ancestors. Workaround: set `POLARS_OVERRIDE_TOTAL_MEMORY_MB` before importing polars. ### Expected behavior ### Installed versions
Panick when Parsing `Map` from ND-JSON
...of `read_ndjson`, and got the same result. I did get a different error earlier: But was unable to reproduce it later to provide a log output. ### Expected behavior Get a DataFrame including the column of Map type. ### Installed versions
Publish free-threaded (cp315t) wheels for polars-runtime
polars 2.0.0's runtime packages (`polars-runtime-32`, `-64`, `-compat`) only ship cp310-abi3 wheels. abi3 wheels can't be installed on free-threaded CPython, so on 3.15t (and 3.14t) pip falls back to building the Rust sdist from source. That needs a Rust toolchain and takes a...
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...
Infinite recursion on `log()` on struct
### 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 Segfaults, due to infinite...
User guide: CSV page has no example reading from a URL or with real data
...in both the Python and Rust source files. I can verify the Python side, but I have no way to compile and verify the Rust equivalent (HTTP CSV needs the `cloud` feature), so my draft adds the section as a plain fenced Python block outside the macro system. Happy to do it either...
More (efficient) `Map` operations
We are missing some key operations like `.map.get(k)` in DSL. The issue is that this, in and of itself, is not efficiently implementable, because we just store the map entries in the input order. So, we would need to rethink how we store a map. Some possibilities are: - Have an...
GPU support for `Map`
Some functionality in `crates/polars-python/src/lazyframe/visitor/expr_nodes.rs` just returns `Err` for `Map`s, even though the equivalent functionality for `List(Struct)` is already there. It might require some changes in `cuDF` though.
Segfault on `exp()` on struct
### 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 Segfault when calling `exp()`...
Add `LazyFrame.optimize` / `LazyFrame.resolve`
### Description As shown by #25246 (and AFAIK it has been requested many more times), it would be relatively useful to be able to cache the optimization or perform optimization in parts. Together with #29003, it should allow a suitable solution for #25246. Implementation-wise,...
Companies and products named
About this problem
Evidence
22 posts from 15 people in 1 place, about 2 a week over 63 days. Mostly on pola-rs/polars. Tools named alongside: PyPI, GitHub, Kubernetes, Docker.
Frustration Frustration 0 of 3· Seen on GitHub issues
Summary, model-written
Polars users experience missing Map operations, compilation verification issues, error returns for Map expressions, and suboptimal query optimization settings.
How it was grouped
Posts about Polars that state a pain but match no known issue yet. First post Aug 27, 2026, latest Oct 28, 2026. Corroborated: 3 or more posts from 2 or more people or places. Method
Other Polars problems
Polars upgrades break working setups
23 posts from 16 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 20 posts from 16 people on GitHub issues, Stack Overflow.
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 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 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.
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.
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.
Polars error messages are cryptic
3 posts from 2 people on GitHub issues.
Trouble with Polars value
Top post: "polars.read_excel() value error on very large date", one of 3 posts from 3 people on GitHub issues.
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