Answer : A, B, E, G
Option A is correct -STL system tables are generated from Amazon Redshift log files to provide a history of the system.
These files reside on every node in the data warehouse cluster. The STL tables take the information from the logs and format them into usable tables for system administrators. To manage disk space, the STL log tables only retain approximately two to five days of log history, depending on log usage and available disk space. If you want to retain the log data, you will need to periodically copy it to other tables or unload it to Amazon S3.
https://docs.aws.amazon.com/redshift/latest/dg/c_intro_STL_tables.html
Option B is correct -STV tables are actually virtual system tables that contain snapshots of the current system data.
https://docs.aws.amazon.com/redshift/latest/dg/c_intro_STV_tables.html
Option C is incorrect -STV tables are actually virtual system tables that contain snapshots of the current system data.
https://docs.aws.amazon.com/redshift/latest/dg/c_intro_STV_tables.html
Option D is incorrect -STL system tables are generated from Amazon Redshift log files to provide a history of the system.
These files reside on every node in the data warehouse cluster. The STL tables take the information from the logs and format them into usable tables for system administrators. To manage disk space, the STL log tables only retain approximately two to five days of log history, depending on log usage and available disk space. If you want to retain the log data, you will need to periodically copy it to other tables or unload it to Amazon S3.
https://docs.aws.amazon.com/redshift/latest/dg/c_intro_STL_tables.html
Option E is correct - There are two types of system tables: STL and STV tables.
STL tables are generated from logs that have been persisted to disk to provide a history of the system. STV tables are virtual tables that contain snapshots of the current system data. They are based on transient in-memory data and are not persisted to disk-based logs or regular tables. System views that contain any reference to a transient STV table are called SVV views. Views containing only references to STL tables are called SVL views. System tables and views do not use the same consistency model as regular tables. It is important to be aware of this issue when querying them, especially for STV tables and SVV views
https://docs.aws.amazon.com/redshift/latest/dg/c_types-of-system-tables-and-views.html
Option F is incorrect -There are two types of system tables: STL and STV tables.
STL tables are generated from logs that have been persisted to disk to provide a history of the system. STV tables are virtual tables that contain snapshots of the current system data. They are based on transient in-memory data and are not persisted to disk-based logs or regular tables. System views that contain any reference to a transient STV table are called SVV views. Views containing only references to STL tables are called SVL views. System tables and views do not use the same consistency model as regular tables. It is important to be aware of this issue when querying them, especially for STV tables and SVV views
https://docs.aws.amazon.com/redshift/latest/dg/c_types-of-system-tables-and-views.html
Option G is correct -There are two types of system tables: STL and STV tables.
STL tables are generated from logs that have been persisted to disk to provide a history of the system. STV tables are virtual tables that contain snapshots of the current system data. They are based on transient in-memory data and are not persisted to disk-based logs or regular tables. System views that contain any reference to a transient STV table are called SVV views. Views containing only references to STL tables are called SVL views. System tables and views do not use the same consistency model as regular tables. It is important to be aware of this issue when querying them, especially for STV tables and SVV views
https://docs.aws.amazon.com/redshift/latest/dg/c_types-of-system-tables-and-views.html