Your Database Machine has a large database with some very large tables supporting OLTP
workloads.
High volume Insert applications and high volume update workloads access the same tables.
You decide to compress these tables without causing unacceptable performance overheads to the
OLTP application.
Which three are true regarding this requirement?
A.
Using’compress for oltp’will compress the data less than if using Hybrid Columnar Compression
when specified with compress for query low.
B.
The compression is performed on the storage servers when using compress for oltp in an
Exadata environment.
C.
The compression method compress for archive high is the worst fit for this requirement.
D.
Using’compress for oltp’will compress the data more than if using Hybrid Columnar
Compression when specified with compress for archive low.
E.
The compression is performed on the database servers when using’compress for oltp’in an
Exadata environment.
Explanation:
Note:
(E not B):
*Types of compression
Basic compression
OLTP compression
Warehouse compression
Online archival compressio
*
/OLTP compression allows compression during DML operations.
/Basic compression works at the data block level.
*When you enable table compression by specifying COMPRESS FOR OLTP, you enable OLTP
table compression. Oracle Database compresses data during all DML operations on the table.
This form of compression is recommended for OLTP environments.
* When you specify COMPRESS FOR QUERY or COMPRESS FOR ARCHIVE, you enable hybrid
columnar compression. With hybrid columnar compression, data can be compressed during bulk
load operations. During the load process, data is transformed into a column-oriented format and
then compressed. Oracle Database uses a compression algorithm appropriate for the level you
specify. In general, the higher the level, the greater the compression ratio.
Hybrid columnar compression can result in higher compression ratios, at a greater CPU cost.
Therefore, this form of compression is recommended for data that is not frequently updated.
A is right. compress for oltp has less compression ratio compared with HCC
B is wrong. compression is done at compute nodes
C is right. there a lot of insert/updates on this table
D is wrong. opposite to answer A
E is right. compression is done at compute nodes
So A.C.E. are correct
A.C.E. are correct