Instruction file imported from Louage/frw-agentic-coding (.github/instructions/al-performance.instructions.md). Copyright stays with the author.

AL Performance — Micro Rules

Hard safety-net rules. Patterns, AL0896 triage and examples live in skill-performance.

1. SetRange/SetFilter before Find/FindSet/FindFirst. Filter early, do not process then filter.
2. SetLoadFields before Get/Find when only some columns are used. Order matters: SetLoadFields → SetRange → Find. Do not list primary-key fields — the platform loads them automatically; including them is dead weight (e.g. Customer.SetLoadFields("VIP Customer"), not ("No.", "VIP Customer")).
3. CalcSums instead of accumulation loops. If you need a total, do not iterate and sum — use the platform aggregation.
4. No database calls inside loops (Get, FindFirst, CalcFields per record). Preload into Dictionary/temporary or use SetAutoCalcFields before the loop.
5. One write per modified record: compute all changes in memory and issue a single Modify(true).