32c40bbf1d
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>
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Use CalcSums to aggregate filtered sets
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
When the task is to compute a sum over a filtered set, CalcSums lets the platform push the aggregation down to SQL using SIFT indexes. Iterating rows in AL to accumulate a total transports every row's data to the runtime only to discard it after adding one field. On ledger-entry-scale tables this difference is dramatic. The same SIFT infrastructure backs Sum-style FlowFields; when the value you need is already declared as a FlowField, calling CalcSums on the underlying table with the correct filters produces the same aggregate.
Best Practice
Set the required filters on the record, then call CalcSums on the field you want aggregated. Ensure the table has a key whose SumIndexFields includes the summed field and whose key prefix matches the filters (see add-sift-keys-for-flowfields).
See sample: samples/performance/use-calcsums-for-flowfield-totals/good.al.
Anti Pattern
Looping a filtered set with FindSet and adding a field to an accumulator on every iteration performs work in AL that SQL already knows how to do in one aggregate query.
See sample: samples/performance/use-calcsums-for-flowfield-totals/bad.al.