Use Views with MongoDB Search

Permissions Required

To create a View, your role must have the createCollection privilege.

Examples

The following examples show how to create a view, create a partial index, and run queries that use the index. The examples query the index by running the .aggregate command against the source collection or the view. MongoDB Search supports queries on views directly only on MongoDB v8.1 or later.

Edit a View

The following example updates the movies_ReleasedAfter2000 MongoDB View for movies before 2000.

db.runCommand(
{
    collMod: "movies_ReleasedAfter2000",
    viewOn: "movies",
    "pipeline": [
      {
        $match: {
          $expr: {
            $lt: [
              "$released",
              ISODate("2000-01-01T00")
            ]
          }
        }
      }
    ]
  }
)

After you run this command, MongoDB Search automatically detects the change in the View definition and performs reindexing with no downtime.

Return the Pipelines for a View

The following example returns the pipelines on the movies_ReleasedAfter2000 View.

db.getCollectionInfos({ name: "movies_ReleasedAfter2000" })[0].options.pipeline

[
  {
    '$match': {
      '$expr': { '$gt': [ '$released', ISODate('2000-01-01T00:00:00.000Z') ] }
    }
  }
]

Performance Considerations

Highly complex view transformations can increase indexing and query time. This is because the mongod must read the view definition when it filters and transforms the oplog entries during indexing (initial sync and steady state replication), and when it applies those transformations to the returned documents at query-time.

Consider creating a materialized view to avoid extra replication load on Atlas. You can also query the source collection directly to avoid query latency from the view transformation.

Troubleshoot

Index Process

When you create an MongoDB Search index on a View, the mongot process performs the same tasks as when you create an MongoDB Search index on a regular collection. The mongot process:

1. Creates MongoDB Search indexes based on the rules in the index definition for the collection.

2. Monitors change streams for the current state of the documents and indexes for the collections for which you defined the MongoDB Search indexes.

3. Processes MongoDB Search queries and returns the document IDs and other search metadata for the matching documents to mongod, which then does a full document lookup and returns the results to the client.

When you create an MongoDB Search index on a View, the View definition is applied during Step 1 and 2, and the transformed documents are indexed based on the search index definition, then stored on disk.

Learn More

To learn more about Views, see Views.

To create a MongoDB Vector Search index on a View, see Use Views with MongoDB Vector Search.