bcquality/microsoft/knowledge/performance/prefer-get-for-primary-key-lookups.md
Jesper Schulz-Wedde 32c40bbf1d Seed performance knowledge corpus (22 articles + AL samples)
Converts an existing performance-review prompt into 22 atomic
knowledge articles under microsoft/knowledge/performance/, each
paired with AL samples under samples/performance/<slug>/ demonstrating
the anti-pattern and/or the best practice. The full set seeds the
corpus the microsoft/skills/al-performance-review leaf skill matches
against and validates the READ knowledge-file format end-to-end.

Every article conforms to the READ contract: six required frontmatter
fields, Description always present, no fenced code blocks, sample
code referenced by repo-relative path. Each article is marked with a
blockquote 'Seed article' note so domain stewards can extend or
restructure them freely.

Articles (ordered by concern area):

Database query efficiency
- use-findset-with-next (AA0181)
- avoid-findfirst-with-next (AA0233)
- only-fetch-records-you-use (AA0175)
- use-findset-readonly-by-default
- use-setloadfields-for-partial-records
- use-addloadfields-in-report-layouts
- use-calcsums-to-aggregate-filtered-sets (file: use-calcsums-for-flowfield-totals.md)
- avoid-calcfields-in-loops
- add-sift-keys-for-flowfields (AA0232)
- use-isempty-for-existence-checks

Filter and key optimization
- filter-before-find
- set-current-key-to-match-filters

Temporary tables and transactions
- use-temporary-tables-for-intermediate-data
- keep-transaction-scope-short
- avoid-user-interaction-in-transactions
- avoid-commit-inside-loops

Record operations
- prefer-get-for-primary-key-lookups
- use-insert-false-when-skipping-triggers
- prefer-direct-record-over-recordref

Strings, codeunits, events
- use-strsubstno-for-message-formatting
- use-single-instance-codeunits-for-caching
- keep-event-subscribers-lightweight

samples/README.md documents the sample-folder convention and makes
clear the samples are demonstration-only, not derived from BC base
application source, with unique object IDs in the 50100-50199 range.

Rubber-duck pass caught: a misleading good.al in avoid-calcfields-in-loops
(fixed by switching to a hoistable CalcFields scenario), an invalid
event subscriber signature in keep-event-subscribers-lightweight
(fixed by adding var xRec), normative guidance leaked into the
Description of use-findset-readonly-by-default (moved to Anti Pattern),
a missing sample pair for keep-transaction-scope-short (added), and
muddy FlowField/CalcSums framing (retitled and clarified).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-04-17 13:23:34 +02:00

1.1 KiB

bc-version domain keywords technologies countries application-area
26..28
performance
get
findfirst
primary-key
lookup
al
w1
all

Prefer Get for primary-key lookups

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

Get is a direct primary-key lookup: one index seek, one row, done. FindFirst with SetRange on the primary key fields reaches the same row through a more general code path and carries the overhead of filter setup and a broader optimizer decision.

Best Practice

When the complete primary key is known, call Get. Use FindFirst only for non-primary-key lookups or when the filter is a partial prefix of the key.

See sample: samples/performance/prefer-get-for-primary-key-lookups/good.al.

Anti Pattern

Setting one SetRange per primary-key field and then calling FindFirst reproduces Get with more typing and slightly worse performance.

See sample: samples/performance/prefer-get-for-primary-key-lookups/bad.al.