What is the ‘FILLFACTOR’?

A “FILLFACTOR” is one of the important arguments that can be used while creating an index.

According to MSDN, FILLFACTOR specifies a percentage that indicates how much the Database Engine should fill each index page during index creation or rebuild. Fill-factor is always an integer valued from 1 to 100. The fill-factor option is designed for improving index performance and data storage. By setting the fill-factor value, you specify the percentage of space on each page to be filled with data, reserving free space on each page for future table growth.

Specifying a fill-factor value of 70 would imply that 30 percent of each page will be left empty, providing space for index expansion as data is added to the underlying table. The fill-factor setting applies only when the index is created or rebuilt.

* Fill-factor settings of 0 and 100 are equal!

What are Points to Remember while Using the FILLFACTOR Argument?


  1. If fill-factor is set to 100 or 0, the Database Engine fills pages to their capacity while creating indexes.
  2. The server-wide default FILLFACTOR is set to 0.
  3. To modify the server-wide default value, use the sp_configure system stored procedure.
  4. To view the fill-factor value of one or more indexes, use sys.indexes.
  5. To modify or set the fill-factor value for individual indexes, use CREATE INDEX or ALTER INDEX statements.
  6. Creating a clustered index with a FILLFACTOR < 100 may significantly increase the amount of space the data occupies because the Database Engine physically reallocates the data while building the clustered index.

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