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Partial Index In Mongodb

In this article, we will discuss partial index in MongoDB.

Purpose

Partial indexes only index the documents in a collection that meet a specified filter expression.

Consider the following collection: -

The next step is to create the partial index.

db.restaurants.createIndex(
   { borough: 1, cuisine: 1 },
   { partialFilterExpression: { 'rating.grade': { $eq: "A" } } }
)

The final step is to use the explain command.

db.restaurants.find( { borough: "Bronx", 'rating.grade': "A" } ).explain("executionStats")

The stage parameter is IXSCAN.

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