agent failed with error when profiling snowflake table for schema drift

TL;DR

Make the agent's Snowflake profiling metadata-first: read column definitions from the information schema, sample only the tables whose schema changed since the last profile, and paginate by schema and table instead of scanning table contents. Schema drift lives in metadata, so a profiling run that reads data rows is doing the expensive thing for no benefit.

agent failed with error when profiling snowflake table for schema drift

Use this when

• The check or run fails with this symptom: the agent errors during its Snowflake schema-drift profiling run.
• You are working on an agent failing while profiling a Snowflake table for schema drift and the failure repeats on the same data or configuration.
• You need the failing rows, rule, or stage isolated before changing thresholds or code.

Not for this skill when

• A value-level drift check, where data sampling is genuinely required instead.
• The error text names a different tool, stage, or root cause. Match the verbatim error first and use that skill.

Steps

1. Review the agent's queries and separate metadata reads from data reads, noting which data reads the drift check actually needs. Verify: metadata and data reads are separated with justification per read
2. Switch drift detection to information schema comparisons against the stored previous schema snapshot. Verify: drift is computed from metadata snapshots
3. Restrict data sampling to tables whose metadata changed, and cap the sample per table. Verify: only changed tables are sampled, with a cap
4. Store the new schema snapshot per table as the run completes so a failure leaves partial progress. Verify: snapshots are stored incrementally per table
5. Rerun the profiling across the database and confirm it completes with a drift list and no full scans issued. Verify: the run completes with a drift list and metadata-only queries for unchanged tables

Variant phrasings

agent failed profiling snowflake schema drift

The verbatim Snowflake agent phrasing.

snowflake schema drift information schema snapshot compare

The metadata-snapshot phrasing.

agent schema profiling metadata first snowflake

The metadata-first phrasing for agent run design.

Compatibility: Agent schema-drift profiling on Snowflake using information schema and account usage

Why it happens

Schema drift is a metadata question, but agents often profile by reading tables because that is the generic pattern. On Snowflake the metadata is complete and cheap, while table reads are billed and slow, so the generic pattern produces the failure.

Edge cases / pitfalls

• Snapshot schemas on a schedule independent of the agent so drift history survives agent failures.
• Watch information schema latency on very large accounts; paginate by schema to keep each read small.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_8frY7NIS95PtwhA0XIMnvQ