Unisoft Technologies Nagpur

Table Compression: Overview Oracle Database supports three methods of table compression: • Basic table compression • OLTP table compression Oracle Corporation recommends to compress all data to reduce storage costs. The Oracle database can use table compression to eliminate duplicate values in a data block. For tables with highly redundant data, compression saves disk space and reduces memory use in the database buffer cache. Table compression is transparent to database applications. • The table_compression clause is valid only for heap-organized tables. The COMPRESS keyword enables table compression. The NOCOMPRESS keyword disables table compression. NOCOMPRESS is the default. • With basic compression, the Oracle database compresses data at the time of performing bulk load using operations such as direct loads or CREATE TABLE AS SELECT . • With COMPRESS FOR OLTP , the Oracle database compresses data during all DML operations on the table.