Fill factor

The default fill factor is determined by the value of the fill factor configuration parameter. There is seldom a reason to change the fill factor parameter.

You can identify a fill factor to specify how full each index page can be. The amount of empty space on an index page is important because when an index page fills up, the system must take time to split it to make room for new rows.

If the default value is 0, you can enter a percentage from 0 to 100. If the default value is other than 0, only percentages from 1 to 100 are valid. A fill factor of 0 does not mean the pages are empty, but means there is some room for additional data. Use a fill factor of 100 only for read-only tables to which no additional data will ever be added. Small fill factors cause each index to take more storage space and result in index pages that are not completely full.

The fill factor percentage is relevant only at the time an index is created. As the data changes, the pages are not maintained at any particular level of fullness.