knowledge(performance): add community rules for JIT, locks, and false positives

These articles capture BC-specific mechanics agents still invert: partial-record JIT on writes, Reset clearing SetLoadFields, HttpClient inside write transactions, and batched number series, plus negative guidance that stops over-eager Query and IsEmpty "fixes".

Co-authored-by: Cursor <cursoragent@cursor.com>

community/knowledge/performance/batch-number-series-instead-of-getnextno-per-row.md

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+---
+bc-version: [22..]
+domain: performance
+keywords: [no-series, getnextno, no-series-batch, savestate, numbersequence, lock]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# Batch number-series calls instead of GetNextNo per insert
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+
+`Codeunit "No. Series".GetNextNo` updates and locks the number-series line on every call. A tight `Insert` loop that asks for a number per row serializes every concurrent writer on that series — the classic SaaS posting bottleneck. Training data still copies the per-row C/AL `NoSeriesManagement` shape. Codeunit `"No. Series - Batch"` issues numbers in memory and writes the series line once via `SaveState`. `NumberSequence` is the alternative when gaps are acceptable.
+
+## Best Practice
+
+Inside a multi-row insert, call `"No. Series - Batch".GetNextNo` per row and `SaveState` once after the loop when the series must remain gapless. Use `NumberSequence.Next` when holes are allowed. Do not replace a single `OnInsert` `GetNextNo` for one master record; that path is not the hotspot.
+
+See sample: `batch-number-series-instead-of-getnextno-per-row.good.al`.
+
+## Anti Pattern
+
+`NoSeries.GetNextNo(...)` inside `repeat ... Insert ... until Next() = 0`. Each iteration takes the series lock. The signal is `"No. Series"` (not `"No. Series - Batch"`) in a loop that inserts more than one row.
+
+See sample: `batch-number-series-instead-of-getnextno-per-row.bad.al`.