Index only documents matching a filter.
Section: MongoDB index types
Partial index
javascript
javascript
db.orders.createIndex(
{ createdAt: -1 },
{ partialFilterExpression: { shippedAt: { $exists: false } } }
)Explanation
A strong way to shrink index size for hot subsets such as unshipped orders.
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Related commands
Same sheet · prioritizing MongoDB index types
Multikey index on an array field
Index documents that contain array values.
Wildcard index
Support flexible queries on unknown or varying fields.
Explain a query with execution stats
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