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Table Compression
Table compression saves space, lowers I/O counts
Notes:
Oracle9i Release 2 provides a table compression feature. Each block in a compressed table contains a symbol table so that repeated values exist only once.
Significant space and I/O savings can be realized. Data warehouse environments can really benefit from this.
Visit asktom.oracle.com and search on “oracle9i compression” for examples and performance tests.
Supplemental Notes
These operations support compression:
Direct path INSERT (insert /*+ append */ …)
Create table as select
SQL*Loader direct path loads
Alter table Moves
UPDATE and INSERT operations are not compressed.