Answer
A covered query is satisfied entirely from an index without touching the collection, improving performance by reducing disk access.
Quick Answer
A covered query is satisfied entirely by the index - MongoDB never reads the actual documents. This is the fastest possible query execution. For a query to be covered: all queried fields must be in the index, all projected fields must be in the index, and _id must be excluded from the projection (unless also in the index). Verify with explain() - look for "totalDocsExamined: 0".
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ