[PR #21588] [MERGED] perf: Fix O(n²) perf issue #113462

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GiteaMirror · 2026-05-18T13:50:45-05:00

GiteaMirror commented

2026-05-18 13:50:45 -05:00

📋 Pull Request Information

Original PR: https://github.com/open-webui/open-webui/pull/21588
Author: @Classic298
Created: 2/19/2026
Status: ✅ Merged
Merged: 2/19/2026
Merged by: @tjbck

Base: dev ← Head: chat-perf

📝 Commits (1)

a36369e Fix O(n²) performance in get_message_list by replacing insert(0) with append+reverse

📊 Changes

1 file changed (+2 additions, -3 deletions)

View changed files

📝 backend/open_webui/utils/misc.py (+2 -3)

📄 Description

Co-authored-by: Jordan CenteredAxis@users.noreply.github.com

This PR should greatly improve the performance when sending a message (latency before the model starts responding) and when searching across chats.

get_message_list is called in middleware.py during message processing (when you send a message). It's used to build the conversation history that gets sent to the LLM. It's also called in routers/chats.py for search (lines 165, 318) and in retrieval/utils.py for RAG context building.

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_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/open-webui/open-webui/pull/21588 **Author:** [@Classic298](https://github.com/Classic298) **Created:** 2/19/2026 **Status:** ✅ Merged **Merged:** 2/19/2026 **Merged by:** [@tjbck](https://github.com/tjbck) **Base:** `dev` ← **Head:** `chat-perf` --- ### 📝 Commits (1) - [`a36369e`](https://github.com/open-webui/open-webui/commit/a36369e945036c7749fca39671d041eda41ae86b) Fix O(n²) performance in get_message_list by replacing insert(0) with append+reverse ### 📊 Changes **1 file changed** (+2 additions, -3 deletions) <details> <summary>View changed files</summary> 📝 `backend/open_webui/utils/misc.py` (+2 -3) </details> ### 📄 Description Co-authored-by: Jordan <CenteredAxis@users.noreply.github.com> **This PR should greatly improve the performance when sending a message (latency before the model starts responding) and when searching across chats.** get_message_list is called in middleware.py during message processing (when you send a message). It's used to build the conversation history that gets sent to the LLM. It's also called in routers/chats.py for search (lines 165, 318) and in retrieval/utils.py for RAG context building. ### Contributor License Agreement  By submitting this pull request, I confirm that I have read and fully agree to the [Contributor License Agreement (CLA)](https://github.com/open-webui/open-webui/blob/main/CONTRIBUTOR_LICENSE_AGREEMENT), and I am providing my contributions under its terms. > [!NOTE] > Deleting the CLA section will lead to immediate closure of your PR and it will not be merged in. --- <sub>🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.</sub>

GiteaMirror added the pull-request label 2026-05-18 13:50:45 -05:00

GiteaMirror closed this issue

2026-05-18 13:50:48 -05:00

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Reference: github-starred/open-webui#113462