Snowflake SCD-1 pipelines: partial updates and nulls
Partial change events can erase valid values if a current-state pipeline treats missing fields as replacements.
What happened
Snowflake’s post explains how partial change-data-capture events complicate slowly changing dimension Type 1 pipelines, which retain the current state rather than full history.
Why it matters
Selecting the latest event is insufficient when that event contains only changed attributes. Carrying values forward also requires a clear source contract.
Who it affects: Engineers maintaining customer, account or transaction state from change feeds.
A practical example
A phone-only update should preserve the existing email. An explicit instruction to clear that email needs a distinguishable representation.
What to do next
Document how the feed represents absence, explicit nulls and deletes.
- Test partial updates and intentional nulls.
- Define ordering for late and equal-timestamp events.
- Reconcile backfills against expected current state.
Signal Take
Correct current state depends on event semantics as much as table design.
Scope and limitations
This is a source-based design review. The suggested edge cases have not been executed against a Snowflake deployment.
Sources and editorial record
Snowflake Blog (opens in a new tab)- Source type
- Vendor engineering blog
- Source published
- 8 Jul 2026
- Source checked
- 19 Sept 2026
Prepared with AI assistance and checked against the linked source. This is editorial interpretation, not an independent product benchmark. How we work.