plotly / plotly/dash

polars seems incompatible with long callbacks

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#2,609 3 comments 0 reactions 0 assignees View on GitHub

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bug P3
Dominant language
Python
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Description

Describe your context
dash app with python 3.11.4 deployed on AWS EC2 instance

dash[diskcache]  2.11.1
polars 0.18.11

Describe the bug

When running long callbacks in dash with polars, they run infinitely & don't get collected - I imagine it's something to do with polars parallelism & multithreading? don't run into these issues with pandas

Expected behavior

Callback to run

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the long-callback behavior using the reported Python 3.11.4, Dash 2.11.1, Polars 0.18.11, and diskcache setup on AWS EC2, then compare it with pandas. Trace whether the callback completes and whether its result is collected; done means the Polars callback finishes and is collected like the pandas version.

Written by the indexing model from the issue text.

Assessment

Tech stack
aws, python
Domain
backend, cloud
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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