bcquality/microsoft/knowledge/performance/load-only-primary-key-fields-for-reference-work.md

bc-version	domain	keywords	technologies	countries	application-area
all	performance	setloadfields primary-key reference existence-check memory	al	w1	all

Load only primary key fields for reference work

Contributions welcome — open a PR to refine or extend this article.

Description

Work that uses a record only for its identity — passing it to another procedure that will re-fetch what it needs, queueing a key for later processing, running existence checks, or building a reference collection — does not need non-key payload fields. SetLoadFields with only the primary key fields loads the minimum that preserves record identity while skipping everything else. On wide tables with large text, BLOB, or media fields the difference in memory and transfer is substantial.

Best Practice

When the iterating code's body touches only primary key fields (or passes the record to another procedure that will apply its own SetLoadFields), declare SetLoadFields with just the primary key fields before applying filters and calling FindSet. Callers downstream that need more fields issue their own Get or extend the load explicitly.

See sample: load-only-primary-key-fields-for-reference-work.good.al.

Anti Pattern

Using the default full-record load in loops whose body only reads the primary key, or forwards the record to another codeunit that immediately re-queries. The non-key payload is fetched across the wire and held in memory for the duration of the loop, then discarded unread.

See sample: load-only-primary-key-fields-for-reference-work.bad.al.