Slow performance when rendering comments which contain a large number of commit hashes

Summary

Loading a Pull Request activity screen fails to load and produces an error when the customer has large comments added that contain a hexadecimal number between 7 and 40 characters. Even if the comment is contained within a code-block.

This is further exacerbated if the repository contains a large number of commits. This can cause the database to spike in an attempt to search for and link the 'commit like' characters ultimately taking longer than 60 seconds to process causing the frontend JS to time out.

Steps to Reproduce

1. Produce large comments that contain 'commit-like' hexadecimal characters wrapped within a code-block.
2. Repository with large commit history

Expected Results

The comments are loaded with no issue. Commit hashes are linked appropriately.

Actual Results

The user receives the following error withing the UI:

Server Unreachable 
The server didn't respond. You may retry your request when the server comes back up.

Workaround

No workaround at this time.