What are Heap tables?

heap is a table without clustered index.

Basically tables that are present in the memory and used as temporary table are HEAP tables.

A heap table is way bigger and has generally high fragmentation.

A heap is a table without a clustered index. One or more non clustered indexes can be created on tables stored as a heap. Data is stored in the heap without specifying an order.A heap table is way bigger and has generally high fragmentation.

1. Tables that are present in the memory are called as HEAP tables.
2. When creating a HEAP table in MySql, user needs to specify the TYPE as HEAP. 
3. These tables are now more commonly known as memory tables.
4. These memory tables never have values with data type like “BLOB” or “TEXT”.
5. They use indexes which make them faster. 
6. They use a hashed index and are stored in the memory.
7. This makes them very fast but if MYSQL crashes all data stored in them can be lost.
8. It is very useful as a temporary table.
9. The internal heap tables use 100% dynamic hashing without the overflow areas.
10. They do not have a problem with delete and insert.

When creating a HEAP table in MySql, user needs to specify the TYPE as HEAP. These tables are now more commonly known as memorytables. These memory tables never have values with data type like “BLOB” or “TEXT”. They use indexes which make them faster.

When creating a HEAP table in MySql, user needs to specify the TYPE as HEAP. These tables are now more commonly known as memorytables.