Frequently Asked Questions

Can I run partial string matching Atlas Search queries?

Yes. The following Atlas Search operators support partial string matching queries:

• autocomplete

• wildcard

• regex

Can I perform case-insensitive search with the wildcard or regex operator?

Yes. You can use the wildcard and regex operators with a custom analyzer to perform a case-insensitive search. You can define a custom analyzer with the following tokenizer and token filter to perform a wildcard case-insensitive search:

• keyword tokenizer

• lowercase token filter

Does storedSource support case-insensitive collation on fields?

Yes. The Atlas Search storedSource option stores original values. To perform case-insensitive operations after the $search stage on the results returned using returnStoredSource option, you must set the default collation strength of your collection to 1 or 2 when you create it, and must not specify a different collation in your queries and indexes.

Can I use the shard key to run Atlas Search queries on specific shard(s)?

No, you can't use the shard key to run Atlas Search queries on a specific shard or a subset of shards. In a sharded cluster environment, Atlas Search queries are scatter-gather queries that run on all the shards.

Do queries run on primary or secondary nodes?

By default, queries run on primary nodes. You can configure your read reference or use replica set tags to specify read preference. To learn more, see Atlas Search Overview.

Why is my search index disappearing?

• Double check that you entered the correct database and collection names. If you enter a non-existent database or collection name, the Atlas UI temporarily builds the index and deletes it shortly after.

• If you use the $out aggregation stage to overwrite your collection, you must delete and recreate your search index, as search indexes are not copied to destination collections. To learn more, see $out Index Constraints.

Can I restore Atlas Search indexes from Cloud Backup snapshots?

Atlas doesn't restore Atlas Search indexes from Cloud Backup snapshots. You must manually rebuild Atlas Search indexes on the cluster.

Does Atlas Search work with CSFLE encrypting clients?

Yes, you can use CSFLE encrypting clients to run Atlas Search queries against data in MongoDB version 6.0 and later.

Can I query CSFLE encrypted data?

No, you can't query CSFLE encrypted data using Atlas Search.