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Performance Considerations

Full Text Search runs a new process, called mongot, alongside the mongod process on each host in your Atlas cluster. mongot maintains all Full Text Search indexes on collections in your Atlas databases. The amount of CPU, memory, and disk resources mongot consumes depends on several factors, including your index configuration and the complexity of your queries.

Index Size and Configuration

When you create a Full Text Search index, the default configuration sets field mapping to dynamic, which means that all the data in your collection is actively added to your Full Text Search index. Other options such as enabling highlights can also result in your index taking up more disk space. You can reduce the size and performance footprint of your Full Text Search index by specifying a custom index definition to narrow the amount and type of data that is indexed.

Creating and Updating a Full Text Search Index

Creating a Full Text Search index is resource-intensive. The performance of your Atlas cluster may be impacted while the index builds.

If you change the configuration of a Full Text Search index it must rebuild, which also consumes resources and may affect database performance.

Note

Do not run queries against a Full Text Search index while it is building. You may get incomplete results. Ensure that all nodes in your cluster have the Active status before running Full Text Search queries.

Query Operators and Query Complexity

The complexity level of Full Text Search queries and the type of operators used can affect database performance. Highly complex queries with multiple clauses are resource-intensive, as are queries which use the regex (regular expression) operator.

Full Text Search queries are ranked by score. Queries that return a large number of results are more computationally intensive because they must keep track of all the scores for the result set.

Performance Monitoring

You can monitor your Atlas cluster and view charts with performance statistics on the Atlas Metrics tab. These metrics can help you see how Full Text Search queries and index building affect your cluster’s performance.

Note

If your cluster’s resources are stretched or near the limits of acceptable performance, consider upgrading to a larger cluster size before implementing Full Text Search functionality.