The services layer is the brain of Snowflake. It does a variety of Functions including
Authentication
Infrastructure management
Metadata management
Query parsing and optimization
Access control
When the table is being loaded, Snowflake collects metadata about all the columns in the file at micro partition level and stores it in the metadata services layer. This is done automatically and done for all the columns
When you query against the table, certain queries are fullfilled by the cloud services layer itself, for example: