mirror of
https://github.com/microsoft/BCQuality.git
synced 2026-08-06 09:26:52 +01:00
078b869e33
* Add per-row performance guidance Document SetAutoCalcFields for per-row FlowFields and direct writes on iterated records, with focused reviewer retrieval cues. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 85be3fc4-5253-47b8-ba1b-6b8fd188fcea * Bound commit checkpoints by key range Use a capped ordered query to discover each checkpoint watermark before locking and processing only that key range. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 85be3fc4-5253-47b8-ba1b-6b8fd188fcea * Address performance retrieval review Retrieve Commit-in-loop guidance precisely, process exact checkpoint key lists, and narrow clone-before-write discovery. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 85be3fc4-5253-47b8-ba1b-6b8fd188fcea --------- Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com> Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
28 lines
2.5 KiB
Markdown
28 lines
2.5 KiB
Markdown
---
|
|
bc-version: [all]
|
|
domain: performance
|
|
keywords: [commit, commit-in-loop, per-row-commit, checkpoint, bounded-checkpoint, watermark, topnumberofrows]
|
|
technologies: [al]
|
|
countries: [w1]
|
|
application-area: [all]
|
|
---
|
|
|
|
# Do not Commit inside loops
|
|
|
|
> Contributions welcome — open a PR to refine or extend this article.
|
|
|
|
## Description
|
|
|
|
Commit ends the current write transaction. Calling it inside a per-row loop produces one transaction per iteration and loses the ability to roll back the whole operation atomically; it also interferes with the platform's ability to batch write operations. Most loops need no explicit Commit at all — AL auto-commits the enclosing code module on successful completion (see `understand-implicit-transaction-boundary.md`). When the batch is too large for one transaction, the fix is not a per-row Commit but bounded checkpoints that select an exact list of at most N keys and process only those rows.
|
|
|
|
## Best Practice
|
|
|
|
If the batch is large enough that a single transaction is untenable, use an ordered primary-key watermark and retrieve a bounded next-N key list. `FindSet` is optimized for reading the complete filtered set and isn't implemented as `TOP X`, so calling it over the remaining tail and breaking after N rows does not bound retrieval. The sample uses a query capped by [`TopNumberOfRows`](https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/methods-auto/query/queryinstance-topnumberofrows-method) to fill a temporary key buffer, then takes update locks and modifies only those exact keys. It does not reconstruct an inclusive first-to-last range that concurrent inserts could expand. Commit after the bounded inner loop returns and persist its last selected key as the next watermark. Use a stable key and define how a later run handles records inserted at or below an already committed watermark. A `Codeunit.Run` boundary can also own a chunk when its implicit commit and error behavior fit the caller — see `codeunit-run-as-atomic-sub-operation.md`.
|
|
|
|
See sample: `avoid-commit-inside-loops.good.al`.
|
|
|
|
## Anti Pattern
|
|
|
|
Placing Commit inside `repeat ... until Next() = 0` is almost always a mistake: it is unusual for the correctness of the operation to depend on per-row commits, and the cost of starting a new transaction on every row dominates the work. A capped query that discovers only an upper key and then re-reads an inclusive key range is not exact batching either; concurrent inserts inside that range can enlarge the checkpoint.
|
|
|
|
See sample: `avoid-commit-inside-loops.bad.al`.
|