bcquality/community/knowledge/error-handling/table-event-subscriber-rolls-back-whole-batch.md
Jeremy Vyska 4119417ce4
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Add 15 community knowledge articles from BC Code Intel ingest (#66)
* Add 15 community knowledge articles from BC Code Intel ingest

Ingests net-new /community knowledge from BC Code Intelligence, surviving
the admission test, gray-zone salvage, and dedup against the full corpus.

Domains: ui (6), error-handling (3), performance (2), upgrade (1),
appsource (1), security (1), telemetry (1). The two BC24 No. Series
migration drafts are merged into one article.

Adds good/bad AL samples for the clean-fit articles (error-handling,
performance, security, telemetry). UI and appsource remain knowledge-only.

Validator and knowledge-index checks pass (207 articles).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Correct SetLoadFields JIT-load article to match MS docs

The draft claimed accessing an unlisted field "reloads the entire row"
per record. Microsoft's partial-records docs say otherwise: the platform
does an implicit Get that loads the missing field(s), and in a direct var
loop the first JIT updates the enumerator so later iterations do not
re-load. The genuine per-row penalty is the pass-by-value case, where the
copy's enumerator is not updated.

Rewrite the article around JIT loading and the by-value footgun, rename
the slug from ...full-reload to ...jit-load, and fix the good/bad samples
to demonstrate the by-value repetition accurately.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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Co-authored-by: Jeremy Vyska <jeremy@sparebrained.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-01 14:31:50 +02:00

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---
bc-version: [all]
domain: error-handling
keywords: [table-events, oninsert, onmodify, ondelete, transaction, rollback, commit, batch, subscriber]
technologies: [al]
countries: [w1]
application-area: [all]
---
# A throw in a table-event subscriber rolls back the whole batch
> Contributions welcome — open a PR to refine or extend this article.
## Description
Table-trigger event subscribers (`OnAfterInsertEvent`, `OnAfterModifyEvent`, `OnAfterDeleteEvent`, and their `OnBefore` counterparts) execute synchronously inside the transaction of the write that fired them. Because AL runs on a single implicit transaction with no per-record savepoint, an error raised in such a subscriber rolls back **all work since the last `COMMIT`** — not just the record that triggered it. In a batch loop with no intermediate `COMMIT`s, a single failing record discards the entire batch. The intuition that subscriber validation fails only the current record is wrong on the BC platform.
## Best Practice
Decide the failure granularity deliberately. If a batch must continue past individual failures, do not throw from the table-event subscriber — collect the error (for example via `ErrorInfo`/collectible errors) and let the loop continue, or isolate each record's work behind a `Codeunit.Run` / `if Codeunit.Run() then` boundary so its failure rolls back only that record. Insert intermediate `COMMIT`s only with full awareness of the durability trade-off.
## Anti Pattern
Putting `Error`/`TestField`/`FieldError` validation inside a table-event subscriber and assuming it rejects just the offending record during bulk processing. The first failure unwinds every uncommitted record in the run, turning a one-row data problem into a whole-batch rollback.