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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 667c64a8-eb36-4440-bc41-6a97d8fb5542 Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com>
28 lines
1.1 KiB
Markdown
28 lines
1.1 KiB
Markdown
---
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bc-version: [all]
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domain: performance
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keywords: [case, branch, frequency, control-flow, hot-path]
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technologies: [al]
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countries: [w1]
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application-area: [all]
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---
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# Order case branches by frequency
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> Contributions welcome — open a PR to refine or extend this article.
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## Description
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AL documentation does not guarantee that a `case` statement uses a linear comparison strategy, so branch frequency alone is not proof of a performance issue. Reordering is justified only when profiling on the target runtime shows that a large, heavily skewed `case` is a material hot path. It is not a default review finding.
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## Best Practice
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After profiling confirms the comparison path matters and the runtime frequency is known, list common branches first without changing the set of handled values, fallback behavior, or branch bodies.
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See sample: `order-case-branches-by-frequency.good.al`.
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## Anti Pattern
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Reordering branches based on assumed frequency without profiling, or changing an `else` arm or handled value while making the optimization. The good and bad forms must differ only in branch order.
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See sample: `order-case-branches-by-frequency.bad.al`.
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