Access is slow on a table created from another table (for example, using the CREATE TABLE...AS SELECT statement or the Create Table as Select check box in the Create Table dialog).

Change the storage structure of the table from which you are selecting the data, or specify a storage structure other than heap for the table you are creating.

Space once used by deleted rows is never reused.

Modify the table to reclaim the deleted row space (for example, using the modify statement or the Modify Table Structure dialog). In this case, you can still choose heap as the storage structure.

Selects and updates are slow.

If the table is not small, modify it to another storage structure. Heap is used only for small tables because the entire table is always scanned. Alternatively, you can create a secondary index.

Inserts are not concurrent.

Use row locking if the page size is greater than 4 KB, or modify to another structure. All inserts to a heap table are sent to the last page.