bcquality/microsoft/knowledge/performance/use-setloadfields-for-partial-records.md
Jesper Schulz-Wedde 62dabf9a11 Co-locate AL samples next to their knowledge articles
The /samples/ top-level tree is replaced with sibling files in each
knowledge-layer folder. An article and its demonstrations now live
side-by-side:

  microsoft/knowledge/<domain>/<slug>.md
  microsoft/knowledge/<domain>/<slug>.good.al
  microsoft/knowledge/<domain>/<slug>.bad.al

Rationale:
- Proximity. An article and its paired samples are one unit; the
  filesystem now reflects that.
- Layer ownership. Samples inherit layer precedence for free -- a
  /custom/ fork can override an article and its samples atomically,
  which the shared /samples/ tree previously made awkward.
- Trivial migration path. Action-skill source globs
  (*/knowledge/<domain>/**/*.md) are unchanged; sample discovery is a
  sibling-filename lookup.

Changes:
- git mv of all 65 sample files from samples/<domain>/<slug>/{bad,good}.al
  to microsoft/knowledge/<domain>/<slug>.{bad,good}.al (history preserved).
- Update See-sample references in all 37 articles that ship samples.
- skills/read.md: replace the no-code-blocks bullet with a pointer to a
  new Sample files section that fully specifies the sibling convention,
  the kinds (good/bad + forward-compatible), multi-technology rules,
  demonstration-only status, and layer-precedence behaviour.
- skills/write.md: update the samples pointer to match.
- README.md: annotate the knowledge tree with the sample sibling shape.
- samples/README.md deleted; content lifted into skills/read.md.
- Both generators (C:\temp\gen_performance_knowledge.py,
  C:\temp\gen_security_knowledge.py) updated to emit at the new paths
  and to stop writing samples/README.md. Re-running them is idempotent
  against the committed layout.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-04-17 13:45:33 +02:00

1.5 KiB

bc-version domain keywords technologies countries application-area
26..28
performance
setloadfields
partial-record
blob
bandwidth
al
w1
all

Use SetLoadFields for partial records

Seed article. Converted from an existing performance-review prompt to bootstrap the BCQuality performance corpus. Domain stewards should expand, restructure, and refine as needed.

Description

SetLoadFields instructs the platform to hydrate only the listed fields on a record variable. On wide tables, or tables with BLOB or media fields, the difference is substantial: a Sales Invoice Line has dozens of fields and loading all of them for every row of a large set is wasted bandwidth. Primary key fields, SystemId, and system audit fields are always loaded automatically. SetLoadFields works only with FieldClass = Normal; FlowFields and FlowFilters cannot be partial-loaded.

Best Practice

Call SetLoadFields before FindSet, FindFirst, or Get whenever the code path only reads a subset of fields. List every field that is read during the operation, including fields used in filters, calculations, and downstream function calls. Omitting a field that is later accessed triggers a second round-trip.

See sample: use-setloadfields-for-partial-records.good.al.

Anti Pattern

Iterating a large set and reading only two or three fields without SetLoadFields forces the platform to transport every column for every row, including BLOBs and unused text fields.

See sample: use-setloadfields-for-partial-records.bad.al.