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* 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> * fix(community/performance): address PR #134 review comments Fixes technical inaccuracies and behavioral issues raised during review of the community performance knowledge articles. avoid-currpage-update-in-onaftergetrecord.md - Removed OnAfterGetCurrRecord from the Best Practice section. That trigger is itself implicitly re-entered on every refresh, so placing CurrPage.Update(false) inside it can re-trigger the very loop the rule warns about. Only OnAction remains as the recommended location. batch-number-series-instead-of-getnextno-per-row.md - Scoped the lock/contention claim to gapless (Normal) series only. Added explicit statement that Allow Gaps series use NumberSequence sequences and do not hold the series-line lock, so the anti-pattern detection signal now excludes Allow Gaps series. countapprox-for-progress-not-count.bad.al / .good.al - Changed FindSet(true) to FindSet() in both samples. The loop is read-only; UpdLock is not needed and was misleading. countapprox-for-progress-not-count.md - Qualified the Count() cost claim: it is expensive only when no SIFT key covers all filtered fields (forcing a SELECT COUNT(*)); a filtered count with matching SIFT coverage is cheap. Added a parenthetical noting that SIFT coverage cannot be assumed for arbitrary filters. dataaccessintent-readonly-on-analytical-objects.md - Changed bc-version from [all] to ["16.."]. DataAccessIntent was introduced at runtime 5.0 / BC 16 and has no effect in earlier versions. - Added precision to the supported objects: pages must be PageType=API with Editable=false; for queries, replica routing only applies when the query is exposed via OData/API, not for AL-to-AL calls. httpclient-inside-write-transaction-holds-locks.good.al - Replaced the Commit()-before-HttpClient pattern with a two-codeunit task-deferral pattern. The write completes inside the caller's transaction (locks released naturally when it ends); a TaskScheduler task runs the HTTP call in a separate session where no write- transaction lock is held. httpclient-inside-write-transaction-holds-locks.md - Changed Best Practice to recommend TaskScheduler/job queue deferral as the primary remedy. - Added an explicit warning against Commit() as a generic remedy: it irrevocably commits all prior writes in the current transaction, so a subsequent failure cannot roll them back. Commit() is appropriate only at top-level entry points where partial persistence is intentional. oncompanyopen-subscribers-must-not-do-io.good.al - Added a ClientType guard so the subscriber exits immediately in background task sessions (OnAfterLogin fires there too, which would create an unbounded task chain without the guard). - Added a TaskScheduler.TaskExists idempotency check to avoid queuing duplicate tasks on repeated logins. - Fixed the error-fallback codeunit in CreateTask from a self-reference to 0 (no error codeunit). - Added a 60-second delay (CurrentDateTime() + 60000) so the task does not compete with the login session itself. prefer-related-table-over-extension-on-hot-ledgers.md - Changed bc-version from [all] to ["23.."]. The companion-table join optimisation (single join per base table, automatic exclusion on List/ OData pages with partial records) was introduced in v23. - Scoped the "join is always paid" claim: since v23 the join is excluded on List/ListPart/OData pages when no extension field is loaded under partial-record semantics, but it is still paid on every posting path and any AL code that accesses an extension field. skip-setloadfields-on-write-and-transferfields.bad.al / .good.al / .md - Changed the example scenario from Modify(false) (which is actually valid with a partial record) to TransferFields+Insert into a temporary record, which is a documented full-load operation. - Removed Modify from the list of operations that force a full load. - Added an explicit note in the .md that Modify itself is not in the full-load list; SetLoadFields is safe to use before Modify(false). use-dedicated-lookup-pages-not-full-lists.bad.al - Added a separate CardPart page definition (50101) to replace the self-referencing FactBox part that referenced the same list page it was embedded in. A part cannot refer to its own container page. validate-on-partial-record-forces-jit.good.al - Restored SetLoadFields to the good sample so it exercises a partial record and the contrast with .bad.al is field selection, not the absence of the feature. The good sample loads both Name and Search Name (the field Name.OnValidate writes), while the bad sample loads only Name, causing a JIT reload of Search Name on every Validate call. * fix(community/performance): correct httpclient and oncompanyopen good samples httpclient-inside-write-transaction-holds-locks.good.al - Pass Customer.RecordId as the last argument to CreateTask so the task is bound to the single customer that was written, not to all customers. - Declare TableNo = Customer on the task codeunit so the platform loads the bound record into Rec automatically when OnRun executes. - Replace the FindSet loop over all customers with Rec."No.", preserving the one-customer scope of the original SyncCustomerLastName procedure. oncompanyopen-subscribers-must-not-do-io.good.al - Replace Session.GetCurrentClientType() with Session.CurrentClientType(), the correct platform method name. - Fix the idempotency check: TaskScheduler.TaskExists() requires a Guid, not a codeunit integer ID. Store the Guid returned by CreateTask in IsolatedStorage (DataScope::Company) under a fixed key; on the next login read it back as Text, Evaluate it to Guid, and pass that Guid to TaskExists so the type matches the method signature. * fix(community/performance): address review feedback --------- Co-authored-by: Cursor <cursoragent@cursor.com>
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Prefer a related table over stored fields on hot ledgers
Contributions welcome — open a PR to refine or extend this article.
Description
Since v23, all extensions on the same base table share at most one companion-table join, and the platform automatically excludes that join on List, ListPart, and OData pages when partial records are in effect and no extension field is loaded. However, the join is still paid on every posting path and any AL code that accesses an extension field — or that runs without partial-record semantics. On hot tables — G/L Entry, Item Ledger Entry, Cust. Ledger Entry — even a single access per posted row adds up at volume. A related table keyed by the ledger Entry No., optionally surfaced with a FlowField or FactBox, leaves the base read path entirely untouched. Agents extend G/L Entry because it is "where the posting already is".
Best Practice
Put optional, sparse, or integration attributes in a related table with the ledger entry number as primary key. Show them from a FactBox or a FlowField. Use a tableextension stored field only when the value must appear as a native list column and is read on almost every access.
See sample: prefer-related-table-over-extension-on-hot-ledgers.good.al.
Anti Pattern
tableextension on "G/L Entry" (or another posting table) that adds several stored Text/Blob fields used only by one integration. The companion join is paid on every posting and on any AL code path that loads extension fields, even when those columns are not needed for the current operation.
See sample: prefer-related-table-over-extension-on-hot-ledgers.bad.al.