What type of data operation is not performed within a transaction in MongoDB?

In MongoDB, a transaction is designed to provide a way to execute multiple operations in a way that ensures atomicity, consistency, isolation, and durability (ACID properties). While transactions can encompass write operations such as document insertions, updates, and deletions across multiple documents, they do not include read operations.

When considering the nature of database queries, they are fundamentally read operations. A query retrieves data from the database without modifying it. Although read operations can be executed in the context of a transaction, they are not a part of the actual transaction in the sense of modification. Transactions are specifically aimed at ensuring that any changes made to the data are completed fully or not at all, which does not apply to read operations like queries.

In the context of this question, it is important to recognize that while multi-document updates, document insertions, and single-document updates can be executed within a transaction, database queries are distinct from these data manipulation operations. Therefore, they are not considered part of the transactional operations, making the identification of queries as the type of operation not performed within a transaction correct.