ORACLE12C new feature index compression COMPRESS

From the Oracle 12.1.0.2 version, index can be compressed by compress.

Grammar

CREATE INDEX index_name on table_name (col_name) COMPRESS.

Alter INDEX INDEX_NAME REBUILD COMPRESS advanced Low;

Compression space comparison

create table ddeng as select * from  Dba_objects;create index idx_ddeng on ddeng (Object_id,object_name,owner);--  take up space size SQL > select segment_name,bytes/1024/1024 from dba_segments where segment_name  =  ' Idx_ddeng '; segment_name     bytes/1024/1024-------------------- ---------------Idx_ddeng   80--  sql> alter index idx_ddeng  rebuild compress  after compression Advanced low;index altered. Sql> select segment_name,bytes/1024/1024 from dba_segments where segment_name  =  ' Idx_ddeng '; segment_name     bytes/1024/1024-------------------- ---------------Idx_ddeng   22 

Enable COMPRESS Advanced low in dba_indexes.compression value display as enable

Note:

• Advanced index compression isn't supported for bitmap indexes or index-organized tables.

• Advanced index compression cannot is specified on a single column unique index.

This article is from the "focus on Oracle Performance Tuning" blog, so be sure to keep this source http://5073392.blog.51cto.com/5063392/1572107

ORACLE12C new feature index compression COMPRESS