Is MongoDB good for read or write?
Reads are more efficient in MongoDB’s storage engine than they are in Cassandra. Cassandra’s storage engine performs very well on writes because it stores data in an append only format. This makes great use of spinning disk drives that have poor seek times, but can do serial writes very quickly.
What is MongoDB write concern?
Write concern describes the level of acknowledgment requested from MongoDB for write operations to a standalone mongod or to replica sets or to sharded clusters. In sharded clusters, mongos instances will pass the write concern on to the shards.
What does it mean to have write concern in MongoDB?
Write concern describes the level of acknowledgment requested from MongoDB for write operations to a standalone mongod or to replica sets or to sharded clusters. In sharded clusters, mongos instances will pass the write concern on to the shards.
How to disable retryable writes in MongoDB cluster?
Applications which write to the local database will encounter write errors upon upgrading to 4.2-series drivers unless retryable writes are explicitly disabled. To disable retryable writes, specify retryWrites=false in the connection string for the MongoDB cluster.
What happens when W is set to false in MongoDB?
With writeConcernMajorityJournalDefault set to false , MongoDB does not wait for w: “majority” writes to be written to the on-disk journal before acknowledging the writes. As such, “majority” write operations could possibly roll back in the event of a transient loss (e.g. crash and restart) of a majority of nodes in a given replica set.
What is a retryable bulk operation in MongoDB?
Bulk write operations that only consist of the single-document write operations. A retryable bulk operation can include any combination of the specified write operations but cannot include any multi-document write operations, such as updateMany. Bulk write operations that only consist of the single-document write operations.