Oracle Database 11 g - Online Public Access Catalog

CHAPTER 12 ■ DATA WAREHOUSING 527■Note As of Oracle Database 11g Release 1, Oracle Streams does not support SecureFiles, so this technologycannot be leveraged.If the table being redefined happens to be a partitioned table, another great time-savingtechnique will be to use the partition exchange option. During this process, Oracle recommendsusing the nologging option of the SecureFiles LOB storage option. You can reenable loggingonce the migration is complete. Using the documents table that is provided in the previousexample, you can perform a partition-by-partition exchange and migrate from BasicFiles toSecureFiles LOB. First create a new table called DOCS2 with just one of the subsets of the rangepartition key. In the following example, the table DOCS2 is created as a SecureFiles using theCTAS approach:SQL> create table docs22 lob(blob_content) store as securefile (nocache nologging)3 tablespace tools4 as5 select * from documents_parted6* where edba_knowledgebase_category_id=2SQL> /Table created.Now, once the partition data is converted into SecureFiles, you can perform the exchange.You can use the following script to exchange the second partition (DOCUMENTS_P2) with thetemporary table (DOCS2) created earlier. The outage is incurred only for the single partition inquestion.SQL> alter table documents_parted exchange partition documents_p2with table docs2 without validation;Table altered.LOB PrefetchOracle Database 11g improves OCI access of smaller LOB and BFILES. LOB data can be prefetchedand cached while also fetching the locator. Now, you can customize the setting for the oci_attr_default_lobprefetch_size variable in your OCI programs. This value determines theprefetch data size for LOB locators. You can set this as an attribute of your OCI environment orset it within your OCI program. The default value for this attribute is zero, which means thereis no prefetching of LOB data.Data Warehousing New FeaturesData warehousing features are rich with functionality to improve information management. Thefunctionality in Oracle Database 11g includes the ability to change reporting and aggregation