Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Chapter 9: SQL Server Storage and Index Structures
ALTER INDEX
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The ALTER INDEX command is somewhat deceptive in what it does. Up until now, ALTER commands
have always been about changing the definition of your object. You ALTER tables to add or disable constraints
and columns, for example. ALTER INDEX is different — it is all about maintenance and zero about
structure. If you need to change the makeup of your index, you still need either to DROP and CREATE it or
to CREATE and use the index with the DROP_EXISTING=ON option.
As you saw earlier in the chapter, SQL Server gives you an option for controlling just how full your leaf
level pages are and, if you choose, another option to deal with non-leaf level pages. Unfortunately, these
are proactive options. They are applied once, and then you need to reapply them as necessary by
rebuilding your indexes and reapplying the options.
In the upcoming section on maintenance, we’ll look more at the wheres and whys of utilizing this command,
but for now, take it on faith that you’ll use maintenance commands like ALTER INDEX as part of
your regular maintenance routine.
The ALTER INDEX syntax looks like this:
ALTER INDEX { | ALL }
ON
{ REBUILD
[ [ WITH (
[ PAD_INDEX = { ON | OFF } ]
| [[,] FILLFACTOR =
| [[,] SORT_IN_TEMPDB = { ON | OFF } ]
| [[,] IGNORE_DUP_KEY = { ON | OFF } ]
| [[,] STATISTICS_NORECOMPUTE = { ON | OFF } ]
| [[,] ONLINE = { ON | OFF } ]
| [[,] ALLOW_ROW_LOCKS = { ON | OFF } ]
| [[,] ALLOW_PAGE_LOCKS = { ON | OFF } ]
| [[,] MAXDOP =
) ]
| [ PARTITION =
[ WITH (
[ ,...n ] ) ] ] ]
| DISABLE
| REORGANIZE
[ PARTITION = ]
[ WITH ( LOB_COMPACTION = { ON | OFF } ) ]
| SET ([ ALLOW_ROW_LOCKS= { ON | OFF } ]
| [[,] ALLOW_PAGE_LOCKS = { ON | OFF } ]
| [[,] IGNORE_DUP_KEY = { ON | OFF } ]
| [[,] STATISTICS_NORECOMPUTE = { ON | OFF } ]
)
} [ ; ]
Several of the options are common to the CREATE INDEX command, so I will skip redefining those particular
ones here. Beyond that, a fair amount of the ALTER-specific options are fairly detailed and relate
to dealing with things like fragmentation (we’ll get to fragmentation and maintenance shortly) or are