Autonomous Data Warehouse on Shared Exadata Infrastructure

BC.

Autonomous Data Warehouse (ADW) is a fully managed cloud service from Oracle that is designed for data warehousing and analytics workloads. It is built on the Oracle Exadata infrastructure and provides several benefits such as high performance, scalability, security, and automation.

Here are the correct statements about Autonomous Data Warehouse on Shared Exadata Infrastructure:

B. Compression is enabled by default. Autonomous Data Warehouse uses Hybrid Columnar Compression for all tables by default.

Autonomous Data Warehouse (ADW) enables automatic data compression by default. It uses a technique called Hybrid Columnar Compression (HCC) for all tables by default, which is designed to improve the performance of data warehouse queries. HCC stores data in a column-oriented format, which results in better compression ratios and faster query performance. HCC also supports multiple compression levels, allowing you to choose the level that best fits your needs.

D. Parallelism is not enabled by default.

In Autonomous Data Warehouse, parallelism is not enabled by default. Parallelism is the ability to split a large query into smaller parts that can be processed simultaneously by multiple CPUs, which can significantly reduce query execution time. However, enabling parallelism requires careful consideration of the system resources available and the characteristics of the workload. Therefore, Oracle provides the ability to enable parallelism on specific objects and queries based on workload characteristics and user requirements.

A. You have direct access to the database node.

This statement is incorrect. In Autonomous Data Warehouse, you do not have direct access to the database node. Autonomous Data Warehouse is a fully managed service that abstracts the underlying infrastructure from users, so you do not need to worry about the hardware or software components of the system. Instead, you interact with the service through APIs or client tools such as SQL Developer, SQL*Plus, or third-party BI tools.

C. Oracle Database Result Cache is enabled by default for all SQL statements.

This statement is also incorrect. Oracle Database Result Cache is not enabled by default in Autonomous Data Warehouse. Result Cache is a feature that stores the results of a SQL query in memory, allowing subsequent identical queries to retrieve the results from memory instead of executing the query again. While Result Cache can improve query performance in some cases, it can also consume significant amounts of memory and impact overall system performance. Therefore, it is up to the user to enable Result Cache based on workload characteristics and performance requirements.