Why do ROWSTORE tables using HASH indexes use a significant amount of memory even without any rows being added to the table?
Tables created using hash indexes occupy memory even when they are empty. This is because, for a table using the hash index, a hash table of size 32MB is built on all the partitions of the particular database.
Hence, the total memory occupied by an empty table using the hash index would be ->
32 X the number of database partitions.