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Why do you need an index in MongoDB?
Indexes also improve efficiency on queries that routinely sort on a given field. If you regularly issue a query that sorts on the timestamp field, then you can optimize the query by creating an index on the timestamp field: Because MongoDB can read indexes in both ascending and descending order, the direction of a single-key index does not matter.
How big is a list created in MongoDB?
I created a collection in MongoDB consisting of 11446615 documents. Each document has the following form: words: words parsed from the url above. Size of the list is between 15 and 90.
How to optimize query performance in MongoDB?
When you need only a subset of fields from documents, you can achieve better performance by returning only the fields you need: For example, if in your query to the posts collection, you need only the timestamp, title, author, and abstract fields, you would issue the following command:
How to reduce the number of cursors in MongoDB?
MongoDB cursors return results in groups of multiple documents. If you know the number of results you want, you can reduce the demand on network resources by issuing the limit () method. This is typically used in conjunction with sort operations.
Is there a way to index two fields in Mongo?
I’m afraid there’s no very good solution for this using mongodb at this time. Mongo only uses 1 index per query. So if you want to filter on 2 fields, mongo will use the index with one of the fields, but still needs to scan the entire subset.
How does the$ Inc operator work in MongoDB?
Use MongoDB’s $inc operator to increment or decrement values in documents. The operator increments the value of the field on the server side, as an alternative to selecting a document, making simple modifications in the client and then writing the entire document to the server.
How does hash based sharding work in MongoDB?
To support hash based sharding , MongoDB provides a hashed index type, which indexes the hash of the value of a field. These indexes have a more random distribution of values along their range, but only support equality matches and cannot support range-based queries.
Why are write operations so slow in MongoDB?
The capability of the storage system creates some important physical limits for the performance of MongoDB’s write operations. Many unique factors related to the storage system of the drive affect write performance, including random access patterns, disk caches, disk readahead and RAID configurations.
How does MongoDB Atlas help improve database performance?
MongoDB Atlas helps you improve database performance with intelligent index and schema suggestions, automatic data tiering, and workload isolation for analytical queries. The Performance Advisor in MongoDB Atlas automatically analyzes collections experiencing poor performance and recommends indexes to both add and remove.