When to Use Heap
Heap is a good storage structure to use in any of these cases:
• You are bulk-loading data into the table.
• The table is only a few pages long (a lookup table).
• You always retrieve every row in the table without sorting.
• You are using a secondary index on a large table and must conserve space.
Do not use heap for large tables when query performance is the top priority. Heap is also a poor storage structure to use if you look up particular rows by key value.