When a SQL query runs in Teradata, it first reaches a Parsing Engine. The functions of the Parsing Engine include:
- Managing individual user sessions (up to 120).
- Checking whether the objects used in the SQL query exist.
- Checking whether the user has the required privileges against the objects used in the SQL query.
- Parsing and optimizing the SQL queries.
- Preparing the execution plan to execute the SQL query and passing it to the corresponding AMPs.
- Receiving response from the AMPs and sending it back to the requesting client.