Which of the following descriptions about HBase secondary indexes is correct?

According to how the data stream transfers data between two Transformations, what types of data streams can be divided into? (Multiple choice)

Regarding the order of the YARN scheduler allocating resources, which one of the following descriptions is correct?

In the MapReduce process, which of the following are shuffle mechanisms? (Multiple choice)

The Group of LdapServer is a unified group management for users. If a user is added to the group, the dn record of the member will be added to the member attribute of the group.