If the fragmentation level is less than 30 percent, one must use
REORGANIZE on the index, instead of
REORGANIZE index doesn't produce locks on data pages or tables, leaving the object available for users to use, and takes less server resources and CPU utilization, as compared with
REORGANIZE is the process of cleaning up current B-Tree (especially leaf level of index), organizing data pages, and defragmenting it. Unlike
REBUILD, REORGANIZE won't add any new pages; if this is needed, it just cleans up current pages and defragments them.
To decide whether to use a
REORGANIZE index or not, have a look at the fragmentation level of the index first; ...