MongoDB Hide Index

MongoDB Hide Index

In MongoDB, the hideIndex operation is used to hide an index from the query planner. This method is essential for testing the impact of index usage on query performance within MongoDB collections.

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Syntax

db.collection.hideIndex(indexName)

The hideIndex method takes an indexName parameter to specify the name of the index to hide.

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Example MongoDB Hide Index

Let's look at an example of how to use the hideIndex method in the programGuru collection in MongoDB:

1. Hide an Index

db.programGuru.hideIndex("name_index")

This command hides the index named name_index from the query planner in the programGuru collection.

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Full Example

Let's go through a complete example that includes switching to a database, creating a collection, creating indexes, and hiding an index.

Step 1: Switch to a Database

This step involves switching to a database named myDatabase.

use myDatabase

In this example, we switch to the myDatabase database.

Step 2: Create a Collection

This step involves creating a new collection named programGuru in the myDatabase database.

db.createCollection("programGuru")

Here, we create a collection named programGuru.

Step 3: Insert Documents into the Collection

This step involves inserting documents into the programGuru collection.

db.programGuru.insertMany([
    { name: "John Doe", age: 30, email: "john.doe@example.com" },
    { name: "Jane Smith", age: 25, email: "jane.smith@example.com" },
    { name: "Jim Brown", age: 35, email: "jim.brown@example.com" }
])

We insert multiple documents into the programGuru collection.

Step 4: Create Indexes

This step involves creating indexes in the programGuru collection.

db.programGuru.createIndexes([
    { key: { name: 1 }, name: "name_index" },
    { key: { age: -1 }, name: "age_index" },
    { key: { email: 1 }, name: "email_index", unique: true }
])

We create three indexes: an ascending index on the name field, a descending index on the age field, and a unique index on the email field.

Step 5: Hide an Index

This step involves using the hideIndex method to hide an index from the query planner in the programGuru collection.

db.programGuru.hideIndex("name_index")

We hide the index named name_index from the query planner.

Conclusion

The MongoDB hideIndex operation is crucial for testing the impact of index usage on query performance. Understanding how to use this method allows you to efficiently manage and optimize the performance of your MongoDB collections.