Over time, I/O on heap tables can become inefficient as storage becomes fragmented. Deletes and updates can result in:
Many partially filled pages
Inefficient large I/O, since extents may contain many empty pages
Forwarded rows in data-only-locked tables
To reclaim space in heap tables:
Use the reorg rebuild command (data-only-locked tables only)
Create and then drop a clustered index
Use bcp (the bulk copy utility) and truncate table
