Clustered Indexing

Question

Does Clustered index needs one extra table to sort/keep the rows data? When it does the sorting , on each Insert or delete statement or when ? How clustered index store data and how it is different from Non-clustered one.

Answer 1

• The data is the clustered index
• Index sort is on creation/rebuild only
• Inserts may create page splits and pointers
• Deletes leave gaps
• Gaps are removed by index rebuild
• Clustered = data sorted as per definition
• Non-clustered = points to clustered index and has it's own sort

Starter article on Simple-Talk

A more in depth article on Simple-Talk

Edit: Another Simple-Talk article on index maintenance