Question 1,214 of 1,446
PCDE Practice Question: Manage a solution that can span multiple database technologies
A company has a Firestore database in Native mode. They need to run a query that filters on two fields (status and date) and orders by date. The query is slow and returns an error that a matching index is missing. What must the engineer do to resolve this?
⚠ Common exam trap
Google Cloud often tests the misconception that single-field indexes are automatically combined for multi-field queries, or that using 'IN' clauses bypasses indexing requirements, when in fact composite indexes are mandatory for such queries.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a composite index on status and date in the Firebase Console or using gcloud.
Firestore requires a composite index on both the equality filter field (status) and the order field (date) when a query uses equality filters on one field and an order on another. Without this composite index, the query cannot be executed efficiently and returns an error. Creating the composite index via the Firebase Console or gcloud CLI resolves the issue.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable single-field indexes for both fields; Firestore will automatically use them.
Why it's wrong here
Single-field indexes are insufficient for multi-field queries.
- ✗
Rewrite the query using 'IN' clauses to avoid the need for a composite index.
Why it's wrong here
Composite indexes may still be needed depending on the query.
- ✓
Create a composite index on status and date in the Firebase Console or using gcloud.
Why this is correct
Firestore in Native mode requires a composite index for queries that filter on multiple fields or combine filters with ordering. The index must include both fields.
- ✗
Change the database to Datastore mode, which does not require indexes.
Why it's wrong here
Datastore mode also requires composite indexes for similar queries.
Visual reference
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Last reviewed: Jul 4, 2026
This PCDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCDE exam.
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