QueryAPIs Interview Questions | Qdrant | NextRound

1What is Qdrant's Scroll API used for, and why is it preferable to vector search when iterating through matching points?Intermediate

2How does Qdrant Scroll pagination avoid the main performance problem of large SQL OFFSET pagination?Advanced

3What is a realistic batch size for bulk-loading millions of Qdrant points, and what factors should influence it?Intermediate

4Why should point uploads be batched instead of sending one upsert request per point?Beginner

5How does Qdrant combine vector similarity search with structured payload filters?Beginner

6Why did Qdrant consolidate search, recommend, and discovery operations into the Universal Query API?Intermediate

7What is a prefetch stage in Qdrant's Universal Query API, and why would you use multiple prefetches?Intermediate

8How do Reciprocal Rank Fusion and Distribution-Based Score Fusion differ when combining Qdrant prefetch results?Advanced

9How would you retrieve 500 candidates with dense vectors and rerank them using a ColBERT multivector?Advanced

10What is Qdrant's recommend query mode, and how is it different from plain similarity search?Intermediate

11What are must, should, and must_not clauses in a Qdrant payload filter?Beginner

12Why can filtering after an ANN search return too few results when the filter is highly selective?Intermediate

13How does Qdrant's filtered vector search avoid the classic post-filtering problem?Advanced

14How would you implement a geo-radius search for similar items within 5 km of a location in Qdrant?Intermediate

15Why should you create payload indexes for fields that are filtered frequently at scale?Intermediate

16What payload index types does Qdrant support, and how would you choose one for tags versus price?Intermediate

17What is a full-text payload index used for, and how does it differ from an exact-match keyword index?Intermediate

18What is the cost of creating too many payload indexes on a high-write Qdrant collection?Advanced