A high water mark (HWM) is a database parameter that indicates the maximum amount of space that has been used by an Oracle database. It is important to monitor the HWM to ensure that the database has enough space to grow and to avoid performance problems.
There are a few different ways to check the HWM in Oracle. One way is to use the V$BH table. The V$BH table contains information about the buffer cache, including the HWM. To query the V$BH table, you can use the following SQL statement: