- A
Maintain two separate indexes: one for building and one for serving, and swap them after building.
This allows building a new index offline and swapping with minimal downtime.
- B
Use streaming updates to add new embeddings incrementally.
Streaming updates allow near real-time index updates without downtime.
- C
Use batch updates to rebuild the entire index daily.
Why wrong: Batch updates cause downtime and are not real-time.
- D
Increase the number of replicas on the deployed index.
Why wrong: Replicas improve query throughput, not index update frequency.
- E
Use a GPU-powered endpoint for faster indexing.
Why wrong: GPUs are for model inference, not indexing updates.
Question 741 of 1,000
PMLE Serving and Scaling Models Practice Question
This PMLE practice question tests your understanding of serving and scaling models. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company wants to use Vertex AI Vector Search for real-time product recommendations based on user embeddings. They need to update the index frequently with new product embeddings without significant downtime. Which TWO options should they consider? (Choose 2)
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
✓
Maintain two separate indexes: one for building and one for serving, and swap them after building.
Option A is correct because maintaining two separate indexes allows you to build a new index in the background while the existing index continues to serve queries. Once the new index is fully built and validated, you can swap it into production with minimal downtime. This is a common pattern for high-availability systems where index rebuilds are necessary.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Maintain two separate indexes: one for building and one for serving, and swap them after building.
Why this is correct
This allows building a new index offline and swapping with minimal downtime.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Use streaming updates to add new embeddings incrementally.
Why this is correct
Streaming updates allow near real-time index updates without downtime.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Use batch updates to rebuild the entire index daily.
Why it's wrong here
Batch updates cause downtime and are not real-time.
- ✗
Increase the number of replicas on the deployed index.
Why it's wrong here
Replicas improve query throughput, not index update frequency.
- ✗
Use a GPU-powered endpoint for faster indexing.
Why it's wrong here
GPUs are for model inference, not indexing updates.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between scaling serving capacity (replicas) and updating index content, leading candidates to mistakenly choose D or E when the real need is for a zero-downtime update strategy.
Detailed technical explanation
How to think about this question
Vertex AI Vector Search uses a hierarchical navigable small world (HNSW) algorithm for approximate nearest neighbor search. Streaming updates (Option B) allow incremental insertion of new embeddings into the index without a full rebuild, leveraging the index's ability to support real-time mutations. However, streaming updates may cause temporary performance degradation if the index is heavily mutated, so the dual-index swap pattern (Option A) is often used for large-scale or latency-sensitive applications.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
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FAQ
Questions learners often ask
What does this PMLE question test?
Serving and Scaling Models — This question tests Serving and Scaling Models — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Maintain two separate indexes: one for building and one for serving, and swap them after building. — Option A is correct because maintaining two separate indexes allows you to build a new index in the background while the existing index continues to serve queries. Once the new index is fully built and validated, you can swap it into production with minimal downtime. This is a common pattern for high-availability systems where index rebuilds are necessary.
What should I do if I get this PMLE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jul 4, 2026
This PMLE 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 PMLE exam.
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