DBMS: Fill Factor (Definitions)

"An option that specifies how full SQL Server should make each index page. 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." (Patrick Dalton, "Microsoft SQL Server Black Book", 1997)

"Specifies to SQL server how full an index page should be." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"An option used when creating an index to reserve free space on each page of the index. This option accommodates future expansion of table data and reduces the potential for page splits. It is a percentage from 0 through 100 that specifies how much of the data pages should be filled after the index is created." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"The fill factor value is a percentage from 0 to 100 that specifies how much to fill the data pages after the index is created. A fill factor value of 0 does not mean that index pages are left empty but rather that only the leaf pages are filled." (Microsoft Corporation, "Microsoft SQL Server 7.0 Data Warehouse Training Kit", 2000)

"Fill factor defines the amount of free space on each page of the index. You use fill factor when creating indexes. It accommodates future expansion of table data and reduces the potential for page splits." (Anthony Sequeira & Brian Alderman, "The SQL Server 2000 Book", 2003)

"An attribute of an index that defines the amount of free space allotted to each page of the index. FILLFACTOR can be used to allocate space for future expansion. FILLFACTOR is a value from 1 through 100 that specifies the percentage of the index page to be left empty." (Thomas Moore, "EXAM CRAM™ 2: Designing and Implementing Databases with SQL Server 2000 Enterprise Edition", 2005)

"The fill factor of an index indicates how much space to leave open for new data when the index is reorganized during maintenance." (Joseph L Jorden & Dandy Weyn, "MCTS Microsoft SQL Server 2005: Implementation and Maintenance Study Guide - Exam 70-431", 2006)

"An index option that identifies how full an index will be when it is created. For tables that have a lot of INSERTS, setting an indexes fill factor to something other than 0 (indicating 100 percent full) will prevent excessive page splits and the resulting fragmentation of indexes." (Darril Gibson, "MCITP SQL Server 2005 Database Developer All-in-One Exam Guide", 2008)

"An attribute of an index that defines how full the SQL Server Database Engine should make each page of the index." (Microsoft, "SQL Server 2012 Glossary", 2012)

DBMS: Extent (Definitions)

"Whenever a table or index requires space, SQL Server allocates a block of 8 2K pages, called an extent, to the object." (Karen Paulsell et al, "Sybase SQL Server: Performance and Tuning Guide", 1996)

"Eight contiguous pages in SQL. Pages are grouped by eights into extents. Extents are used to allocate space for indexes and tables." (Owen Williams, "MCSE TestPrep: SQL Server 6.5 Design and Implementation", 1998)

"The space allocated upon creation of a SQL Server object, such as a table or index. In SQL Server, an extent is eight contiguous pages." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A group of pages that are allocated together, as part of the initial creation of an object or when an existing extent becomes full." (Peter Gulutzan & Trudy Pelzer, "SQL Performance Tuning", 2002)

"The unit of space allocated to a SQL Server object, such as a table or index, whenever the object needs more space. In SQL Server 2000, an extent is eight contiguous pages." (Anthony Sequeira & Brian Alderman, "The SQL Server 2000 Book", 2003)

"A contiguous group of blocks allocated for use as part of a table, index, and so forth." (Bob Bryla, "Oracle Database Foundations", 2004)

"The basic unit by which space is allocated to a table or an index. An extent is eight continuous disk pages, which equates to 64 KB." (Allan Hirt et al, "Microsoft SQL Server 2000 High Availability", 2004)

"This is a group of eight data pages totaling 64KB in size." (Joseph L Jorden & Dandy Weyn, "MCTS Microsoft SQL Server 2005: Implementation and Maintenance Study Guide - Exam 70-431", 2006)

"A collection of eight contiguous pages used internally by the storage engine in SQL Server 2005 to track the allocation of file space to table and indexes." (Marilyn Miller-White et al, "MCITP Administrator: Microsoft® SQL Server™ 2005 Optimization and Maintenance 70-444", 2007)

"An extent is SQL Server's basic allocation unit of storage. An extent is 64 KB in size and consists of eight logically contiguous data pages, each page being 8 KB in size." (Michael Coles, "Pro T-SQL 2008 Programmer's Guide", 2008)

"On a disk or other direct-access storage device, a continuous block of storage space reserved by the operating system for a particular file or program." (Microsoft, "SQL Server 2012 Glossary", 2012)

"SQL Server’s basic allocation unit of storage. An extent is 64 KB in size and consists of eight logically contiguous data pages, each of which is 8 KB in size." (Miguel Cebollero et al, "Pro T-SQL Programmer’s Guide 4th Ed", 2015)

"An allocation of space, within a container of a table space, to a single database object. This allocation consists of multiple pages." (Sybase, "Open Server Server-Library/C Reference Manual", 2019)