Mongo DB

• October 5, 2010
• Girikon

Main point: Retains some friendly properties of SQL. (Query, index)

Key Features Of Mongo DB:

• Master/slave replication (auto failover with replica sets)
• Sharding built-in Queries are javascript expressions
• Run arbitrary javascript functions server-side
• Better update-in-place than CouchDB
• Uses memory mapped files for data storage
• Performance over features
• Journaling (with –journal) is best turned on
• On 32bit systems, limited to ~2.5Gb
• Text search integrated
• GridFS to store big data + metadata (not actually an FS)
• Has geospatial indexing
• Data center aware

Best used: If you need dynamic queries. If you prefer to define indexes, not map/reduce functions. If you need good performance on a big DB. If you wanted CouchDB, but your data changes too much, filling up disks.

Examples: For most things that you would do with MySQL or PostgreSQL, but having predefined columns really holds you back.
Regards,
Alok