Ways to improve the performance of query operation

Using indexes: Indexes in DDS are similar to those in relational database, which can speed up data query and sorting. In MongoDB, we can create an index using the createIndex method.

Reasonable design of document structure: The data structure in DDS should follow the principle of "nesting", that is, try to put the related data in the same document. This can reduce the I/O operation in data query and improve the query efficiency.

Avoid global scanning: Query operations may become slow when indexes are not available for query conditions. Therefore, we should avoid global scanning as much as possible and optimize queries through paging queries, index merging, etc.

Increase caching: By using caching techniques, you can reduce the access of query operations to the database and improve query efficiency. TTL indexes can be used in MongoDB to implement data caching.

Using aggregate queries: Aggregate queries can group, count, and sort documents, making it easier to handle complex query requirements. An aggregation framework is available in MongoDB to implement these operations.