Address review feedback on retention policy knowledge

- Scope both articles to bc-version [17..] (retention policies shipped in v17).
- Allowed-tables sample: add OnRefreshAllowedTables subscriber with a
  ForceUpdate path; the upgrade tag now gates one-time setup only.
- Default-policy sample: use Retention Policy Setup.FindOrCreateRetentionPeriod
  instead of a hand-rolled lookup-then-insert that can collide on code.
- Anti-pattern now keys on append-only tables rather than table names.
- al-privacy-review: add retention-policy tokens and deterministic routing
  for both articles, with a bounded per-table text search for delete and
  registration paths.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
Jeremy Vyska 2026-09-28 09:41:25 +02:00
parent 2f3e5afac1
commit 4bef582ffe
5 changed files with 37 additions and 30 deletions

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@ -1,7 +1,7 @@
---
bc-version: [all]
bc-version: [17..]
domain: privacy
keywords: [retention-policy, allowed-tables, addallowedtable, reten-pol-allowed-tables, log-table-growth, mandatory-minimum-retention, install-upgrade-codeunit]
keywords: [retention-policy, allowed-tables, addallowedtable, reten-pol-allowed-tables, onrefreshallowedtables, append-only-table, log-table-growth, deleteall, mandatory-minimum-retention, install-upgrade-codeunit]
technologies: [al]
countries: [w1]
application-area: [all]
@ -15,7 +15,7 @@ The retention policy engine only ever deletes from tables that appear in its all
## Best Practice
Register every table the extension owns that accumulates rows over time: activity and audit logs, integration and API request logs, archived documents. Call a shared routine from both the install codeunit (`OnInstallAppPerCompany`) and an upgrade codeunit (`OnUpgradePerCompany`), because install code does not run when an existing installation moves to a new version — registration added only to install code never reaches tenants that already have the app. Guard the routine with `IsAllowedTable` and an upgrade tag so repeated runs are idempotent. Pass `MandatoryMinRetenDays` when the data must survive a minimum period for audit or support reasons; the platform then rejects any shorter period an administrator configures. When only a subset of rows should ever expire, build the filter with `AddTableFilterToJsonArray` and pass it to the `AddAllowedTable` overload that takes a `JsonArray` — a filter added as locked cannot be removed later by the administrator.
Register every table the extension owns that accumulates rows over time: activity and audit logs, integration and API request logs, archived documents. Call a shared routine from both the install codeunit (`OnInstallAppPerCompany`) and an upgrade codeunit (`OnUpgradePerCompany`), because install code does not run when an existing installation moves to a new version — registration added only to install code never reaches tenants that already have the app. Guard the routine with `IsAllowedTable` and an upgrade tag so repeated runs are idempotent, but keep a force path past the tag: the **Retention Policies** pages raise `Reten. Pol. Allowed Tables.OnRefreshAllowedTables`, and the platform's own installers (System Application, Base Application, Shopify) subscribe to it and re-run registration with `ForceUpdate`. A routine that exits whenever the tag is set cannot take part in that refresh, so the upgrade tag should gate one-time setup only, not re-registration. Pass `MandatoryMinRetenDays` when the data must survive a minimum period for audit or support reasons; the platform then rejects any shorter period an administrator configures. When only a subset of rows should ever expire, build the filter with `AddTableFilterToJsonArray` and pass it to the `AddAllowedTable` overload that takes a `JsonArray` — a filter added as locked cannot be removed later by the administrator.
Registering a table only makes it eligible; the policy itself is a separate concern, covered by [`ship-a-default-retention-policy-setup.md`](ship-a-default-retention-policy-setup.md).
@ -23,11 +23,11 @@ See sample: [`register-owned-log-tables-for-retention-policies.good.al`](registe
## Anti Pattern
An extension-owned log table with no `AddAllowedTable` call anywhere in the app, cleaned instead by hand-rolled code — a job queue codeunit or scheduled task running `DeleteAll` against a hard-coded date window. The deletion happens outside the **Retention Policy Log**, the administrator has no page on which to lengthen, shorten, or disable it, and the table is invisible during a data-retention review. The same defect in slower form is registration performed only in the install codeunit: new tenants are covered, every existing tenant stays unregistered after the upgrade.
An extension-owned table that only grows — the app inserts into it but never deletes from it — with no `AddAllowedTable` call anywhere in the app. The name is not a reliable signal: an "Incoming Data" buffer-history table grows the same way an "Activity Log" does, and such tables have reached hundreds of gigabytes on customer tenants. A variant is a table cleaned by hand-rolled code — a job queue codeunit or scheduled task running `DeleteAll` against a hard-coded date window: the deletion happens outside the **Retention Policy Log**, the administrator has no page on which to lengthen, shorten, or disable it, and the table is invisible during a data-retention review. The same defect in slower form is registration performed only in the install codeunit: new tenants are covered, every existing tenant stays unregistered after the upgrade.
See sample: [`register-owned-log-tables-for-retention-policies.bad.al`](register-owned-log-tables-for-retention-policies.bad.al).
## References
- [Clean up data with retention policies](https://learn.microsoft.com/en-us/dynamics365/business-central/admin-data-retention-policies), section *Include your extension in a retention policy*.
- [`RetenPolAllowedTables.Codeunit.al`](https://github.com/microsoft/BCApps/blob/main/src/System%20Application/App/Retention%20Policy/src/Retention%20Policy%20Allowed%20Tables/RetenPolAllowedTables.Codeunit.al) in microsoft/BCApps — the `AddAllowedTable` overloads, `IsAllowedTable`, and `AddTableFilterToJsonArray`.
- [`RetenPolAllowedTables.Codeunit.al`](https://github.com/microsoft/BCApps/blob/main/src/System%20Application/App/Retention%20Policy/src/Retention%20Policy%20Allowed%20Tables/RetenPolAllowedTables.Codeunit.al) in microsoft/BCApps — the `AddAllowedTable` overloads, `IsAllowedTable`, `AddTableFilterToJsonArray`, and `OnRefreshAllowedTables`.