Is the command REORG got anything with improving the performance of database. If so in what way? I want to know what happens inside the database while REORG is done.
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Is the command REORG got anything with improving the performance of database. If so in what way? I want to know what happens inside the database while REORG is done.
it will reorganize the database.
it rebuilds the indexes ,there by increasing the performance
The REORG operation performs the following functions:
1.Checks referential integrity, if applicable for the target table, and either deletes rows that violate it or invalidates any affected indexes. (Referential integrity is the relational property that each foreign-key value in a table exists as a primary-key value in the referenced table.)
2.Performs an internal reorganization of one or more of the indexes for the table (all types) to improve the internal storage of this information and thereby the performance when the index is used to access data. It can rebuild all indexes, selectively rebuild one or more named indexes, or selectively rebuild one or more segments of one or more named indexes.
3.Populates a DEFERRED index that is created with a CREATE INDEX statement. A DEFERRED index is an empty index structure that can be populated at a later date. For more information about DEFERRED indexes
4.Rebuilds precomputed views. For example, if precomputed view maintenance is set to OFF in your application, you can use the REORG command to rebuild precomputed views only, without touching the indexes on the target table. Alternatively, you can use the REORG command to rebuild both indexes and views.