a9f3c50863
The previous LLM-generated knowledge files contained factual
hallucinations. The most visible was the claim that `FindFirst` /
`FindLast` "forces a full-table scan" on an unfiltered record - it does
not; those APIs return a single row via the current key.
Other inaccuracies the audit found and fixed:
* `FindSet(true)` was described as "taking a LockTable". The correct
upstream phrasing is that `FindSet(true)` sets
`ReadIsolation::UpdLock` on the read. UpdLock and LockTable are
related but distinct mechanisms.
* The list of production-scale tables had been invented beyond the
upstream source (e.g. "Detailed Cust. Ledg. Entry") without a
citation. The regenerated list matches the ten tables upstream lists
with their P95 row counts.
* `SetLoadFields` guidance had been augmented with an extra mechanism
claim ("the database resolves the filter using the index without
hydrating the value") not present in upstream.
Approach: full regeneration of `microsoft/knowledge/` from the six
upstream BCApps Code Review instruction files, with Microsoft Learn /
the AL language reference as a secondary source. Every claim in every
regenerated file is anchored to a verbatim upstream quote (or a Learn
URL); the audit trail lives in artifacts/trace-<domain>.json on the
session workspace.
The PR #11 transaction/error-handling cluster is preserved verbatim:
* performance/understand-implicit-transaction-boundary.md
* performance/codeunit-run-as-atomic-sub-operation.{md,good.al,bad.al}
* performance/codeunit-run-requires-prior-commit-inside-transaction.{md,good.al,bad.al}
* performance/use-tryfunction-for-error-catching-not-rollback.{md,good.al,bad.al}
* performance/avoid-commit-inside-loops.{md,good.al,bad.al}
* security/commitbehavior-attribute-scopes-explicit-commits.{md,good.al,bad.al}
* testing/transactionmodel-attribute-governs-test-transactions.{md,good.al,bad.al}
These articles already cite Microsoft Learn and were carefully
cross-referenced; the regeneration skips their topics rather than
duplicating them.
File counts after regeneration:
performance 35 .md (5 preserved + 30 new)
privacy 17 .md
security 18 .md (1 preserved + 17 new)
style 33 .md
testing 1 .md (preserved)
ui 19 .md
upgrade 18 .md
Total 141 atomic knowledge files, each strictly one rule. All pass
.github/scripts/validate_frontmatter.py with 0 errors and 0 warnings.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
1.5 KiB
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Do not Modify inside OnAfterGetRecord
Description
A list page's OnAfterGetRecord fires once per visible row, every time the user scrolls, sorts, or refreshes. A Modify inside that trigger means a database write per row displayed. Per the upstream guidance, "Modify() here means a DB write on every scroll. Use page variables for display-only state instead." OnAfterGetCurrRecord (single record on selection), OnOpenPage, and OnInit fire once or at much lower frequency and tolerate one-time setup logic.
Best Practice
When the trigger needs to compute display-only state per row, write the result into a page variable (a global on the page object) rather than back to the database. Reserve Modify for triggers that fire on an explicit user action — OnAction, validation triggers, OnQueryClosePage — where one action maps to one write.
See sample: do-not-modify-in-onaftergetrecord.good.al.
Anti Pattern
trigger OnAfterGetRecord() begin Rec."Warning Flag" := CalcWarning(); Rec.Modify(); end; — on a list page over a moderately sized table, scrolling through fifty rows produces fifty writes. The page feels slow, the table accumulates churn, and the warning flag — which is recomputed on every refresh anyway — never needed persistence.
See sample: do-not-modify-in-onaftergetrecord.bad.al.