[TT-12840, DX-1620] Added explanation of bug fix missed in 5.4 RN

[andyo-tyk]

DX-1620

---

Preview Link

https://deploy-preview-5260--tyk-docs.netlify.app/docs/nightly/getting-started/key-concepts/rate-limiting/#combining-multiple-policies-configuring-rate-limits
https://deploy-preview-5260--tyk-docs.netlify.app/docs/nightly/product-stack/tyk-gateway/release-notes/version-5.4/

Description

We missed a bug fix from the 5.4 release notes, as it was fixed as part of another change. Adding this to the release notes and also an explanation of the functionality to the main docs.

---

PR Type

Documentation, Enhancement

---

Description

• Added documentation explaining how Tyk combines multiple policies with rate limits, highlighting the corrected behavior in version 5.4.0.
• Updated the release notes to include details of a bug fix in the calculation of effective rate limits when multiple policies are applied to a key.
• Provided a detailed explanation of the previous incorrect behavior and the new corrected logic for rate limit calculations.

---

Changes walkthrough 📝

Relevant files

Documentation

rate-limiting.md Document combining multiple rate limit policies and bug fix tyk-docs/content/getting-started/key-concepts/rate-limiting.md Added explanation for combining multiple policies with rate limits. Clarified the corrected behavior for rate limit calculation. Included a note about the bug fix in rate limit calculation. +14/-0    version-5.4.md Update release notes with rate limit calculation fix          tyk-docs/content/product-stack/tyk-gateway/release-notes/version-5.4.md Updated release notes to include a bug fix for rate limit calculation. Explained the impact of the fix on existing policies. Added a detailed description of the previous and corrected behavior. +16/-1

---

💡 PR-Agent usage:
Comment /help on the PR to get a list of all available PR-Agent tools and their descriptions

[github-actions]

PR Reviewer Guide 🔍

⏱️ Estimated effort to review: 1 🔵⚪⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ No key issues to review

[github-actions]

PR Code Suggestions ✨

Category	Suggestion	Score
Enhancement	Simplify and clarify the explanation of how Tyk calculates effective rate limits when multiple policies are applied To enhance clarity and avoid potential confusion, consider rephrasing the explanation about how Tyk calculates the effective rate limit when multiple policies are applied. The current wording might be too technical for users unfamiliar with the concepts of rate and per. Simplifying the language and providing a clearer example could improve understanding. tyk-docs/content/getting-started/key-concepts/rate-limiting.md [75-79] -If more than one policy defining a rate limit is applied to a key then Tyk will apply the highest request rate permitted by any of the policies that defines a rate limit. +When multiple policies with rate limits are applied to a key, Tyk selects the highest permissible request rate from these policies. -If `rate` and `per` are configured in multiple policies applied to the same key then the Gateway will determine the effective rate limit configured for each policy and apply the highest to the key. +Specifically, if policies have different `rate` and `per` settings, Tyk calculates the effective rate limit for each and applies the highest. For example, if one policy allows 90 requests every 30 seconds (3 requests per second) and another allows 100 requests every 10 seconds (10 requests per second), Tyk will apply the 10 requests per second limit from the second policy. -Given, policy A with `rate` set to 90 and `per` set to 30 seconds (3rps) and policy B with `rate` set to 100 and `per` set to 10 seconds (10rps). If both are applied to a key, Tyk will take the rate limit from policy B as it results in a higher effective request rate (10rps). - Suggestion importance[1-10]: 7 Why: The suggestion improves clarity and readability by simplifying the explanation of how Tyk calculates effective rate limits, making it more accessible to users unfamiliar with technical terms. However, it does not address a critical issue, so it receives a moderate score.	7
	Add a direct link to the detailed explanation of the bug fix in the release notes for better navigation and understanding It is recommended to provide a direct link to the detailed explanation of the bug fix in the release notes. This will help users quickly navigate to the relevant section for a comprehensive understanding of the changes and their impact. tyk-docs/content/product-stack/tyk-gateway/release-notes/version-5.4.md [32] -We have fixed a bug in the way that Tyk calculates the [key-level rate limit]({{< ref "getting-started/key-concepts/rate-limiting#key-level-rate-limiting" >}}) when multiple policies are applied to the same key. This fix alters the logic used to calculate the effective rate limit and so may lead to a different rate limit being applied to keys generated from your existing policies. See the [change log](#fixed) for details of the change. +We have fixed a bug in the way that Tyk calculates the [key-level rate limit]({{< ref "getting-started/key-concepts/rate-limiting#key-level-rate-limiting" >}}) when multiple policies are applied to the same key. This fix alters the logic used to calculate the effective rate limit and so may lead to a different rate limit being applied to keys generated from your existing policies. For a detailed explanation, see the [change log](#fixed) and the [detailed section on rate limiting](#combining-multiple-policies-configuring-rate-limits). Suggestion importance[1-10]: 6 Why: Adding a direct link to the detailed explanation enhances user navigation and understanding of the changes, which is a helpful improvement for documentation usability. However, it is not a critical enhancement, so it receives a moderate score.	6

[netlify]

✅ PS. Pls add /docs/nightly to the end of url

Name	Link
🔨 Latest commit	8233c5f
🔍 Latest deploy log	https://app.netlify.com/sites/tyk-docs/deploys/66c4b31dbd097400087fda48
😎 Deploy Preview	https://deploy-preview-5260--tyk-docs.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[dcs3spp]

PR LGTM, not sure if there was a typo in example given in change log, should 100 requests be updated to 90 requests in 2nd paragraph of the fixed change-log item?

[dcs3spp]

PR LGTM, @lghiur @OldStubbsy would you be able to peer review and if ok approve and then I will merge and release

[OldStubbsy]

Looks good to me. Thanks!

[dcs3spp]

Thanks @lghiur @OldStubbsy for peer approval, I'll publish PR for @andyo-tyk now

[dcs3spp]

/release to release-5.5

[tykbot]

Working on it! Note that it can take a few minutes.

[tykbot]

@dcs3spp Succesfully merged PR

[dcs3spp]

/release to release-5.4

[tykbot]

Working on it! Note that it can take a few minutes.

[tykbot]

@dcs3spp Succesfully merged PR