QuantConnect / QuantConnect/Lean

Stream backtest logs to disk instead of holding in memory

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bug feature impact-low
Dominant language
C#
Stars
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Forks
5.3k
Avg merge
2d 22h
Merged PRs (30d)
34

Description

Expected Behavior

While backtesting stream logs to a temporary file instead of holding in memory to prevent memory issues.

Actual Behavior

Hold entire log in memory

Potential Solution

Adjust the backtest log handler.

Reproducing the Problem

Run a backtest with large volume of logging and monitor memory.

Checklist
  • I have completely filled out this template
  • I have confirmed that this issue exists on the current master branch
  • I have confirmed that this is not a duplicate issue by searching issues

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

Locate the backtest log handler in the Lean codebase and begin by tracing how large-volume backtest logs are currently accumulated. Reproduce the issue with a high-logging backtest while monitoring memory. Done means logs stream to a temporary file instead of remaining entirely in memory, with the backtest output preserved.

Written by the indexing model from the issue text.

Assessment

Tech stack
csharp
Domain
backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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