Data Lake

Wikipedia Definition:
A data lake is a system or  repository of data stored in its natural/raw format, usually object  blobs or files. A data lake is usually a single store of data including raw copies of source system data, sensor data, social data etc.
James Dixon, then chief technology officer at  Pentaho, coined the term by 2011 to contrast it with  [Data Mart].

• Flexible data storage
• Streaming support
• Cost efficient in the cloud
• Support for AI and Machine Learning

• No transactional support
• Poor data reliability
• Slow analysis performance
• Data governance concerns
• Data warehouses still needed

Issues of data lake that are solved by using Delta Lake:

• Lack of ACID transaction support
• Lack of schema enforcement
• Lack of integration with a data catalog
• Ineffective partitioning
• Too many small files
  Poorly-managed data lakes have been facetiously called Data Swamps.