Is it true that cross-project views block partition filter pushdown?

[corgineer]

We’re seeing unexpected performance issues in BigQuery when querying views across projects.

🔍 Context:

• We're querying a view in Project B from a model/table in Project A.

• The view in Project B references a partitioned table and includes a date filter like event_date > TIMESTAMP_SUB(CURRENT_DATE(), INTERVAL 7 DAY).

🛑 Problem:
Despite filtering on event_date, BigQuery appears to scan the entire underlying table behind the view in Project B. The filter doesn’t seem to push down into the view’s execution plan.

✅ When the view and consuming query are in the same project, partition pruning works as expected.

❓Is it expected that cross-project views break partition pruning/filter pushdown?
If so, is materializing the view (as a table) the only reliable workaround for performance?

Appreciate any insights — thanks!

[a_aleinikov]

Hi @corgineer ,

Yes, you're correct — cross-project views can prevent partition filter pushdown in BigQuery. This is expected behavior due to security and permission boundaries.

Workarounds:

• Use authorized views carefully, ensuring permissions allow filter pushdown.

• Or, as you noted, materialize the view into a table in the same project.

This usually restores partition pruning.