※This sample exam is different from those that appear in the actual OSS-DB Exam.
Automatic vacuum is executed by periodically starting automatic vacuum worker from a daemon called automatic vacuum launcher which always exists. It is started automatically at regular intervals and does not take into consideration the load situation etc of the server. Automatic vacuum processes VACUUM and ANALYZE, but only the tables whose update exceeds a certain threshold are processed.
Automatic vacuum is set appropriately to run by default, and the development group of PostgreSQL strongly recommends that this be done.
If you are running automatic vacuuming, the need for manual vacuum vacuuming is low, but there are situations where it is desirable to perform vacuum, such as immediately after updating or deleting a large amount of data.
Therefore, the correct answers are B and E.