How do I reindex a SQL database?

What does it mean to reindex a database?

Description. REINDEX rebuilds an index using the data stored in the index's table, replacing the old copy of the index. There are several scenarios in which to use REINDEX: An index has become corrupted, and no longer contains valid data.

What does reindex do in SQL?

DBCC DBREINDEX rebuilds an index for a table or all indexes defined for a table. By allowing an index to be rebuilt dynamically, indexes enforcing either PRIMARY KEY or UNIQUE constraints can be rebuilt without having to drop and re-create those constraints.

How often should you reindex a SQL database?

There's a general consensus that you should reorganize ("defragment") your indices as soon as index fragmentation reaches more than 5 (sometimes 10%), and you should rebuild them completely when it goes beyond 30% (at least that's the numbers I've heard advocated in a lot of places).

Do I need to reindex SQL Server?

Microsoft recommends fixing index fragmentation issues by rebuilding the index if the fragmentation percentage of the index exceeds 30%, where it recommends fixing the index fragmentation issue by reorganizing the index if the index fragmentation percentage exceeds 5% and less than 30%.