Oracle Database 11 g - Online Public Access Catalog

CHAPTER 12 ■ DATA WAREHOUSING 529The NUM_PCT_TABLES, NUM_FRESH_PCT_REGIONS, and NUM_STALE_PCT_REGIONS columns arenew additions to Oracle Database 11g to show how many detail partitions support PCT and theamount of stale and fresh PCT regions.The ALL_MVIEW_DETAIL_RELATIONS view represents the named detail relations thateither are in the from list of a materialized view or are indirectly referenced through views in thefrom list. Additionally, Oracle provides three new columns to the ALL_MVIEW_DETAIL_RELATIONS view, as shown next, to inform whether PCT is supported and, if so, to show thenumber of fresh and stale partition regions:SQL> desc all_mview_detail_relationsName Null? Type------------------------ ------- -------------....DETAILOBJ_PCTVARCHAR2(1)NUM_FRESH_PCT_PARTITIONSNUMBERNUM_STALE_PCT_PARTITIONSNUMBERThe DETAILOBJ_PCT, NUM_FRESH_PCT_PARTITIONS, and NUM_STALE_PCT_PARTITIONS columnsare new to Oracle Database 11g.Oracle Database 11g introduces a new view called ALL_MVIEW_DETAIL_PARTITION toprovide freshness information for each PCT partition, as shown here:SQL> desc all_mview_detail_partitionName Null? Type------------------------- -------- -----------------OWNER NOT NULL VARCHAR2(30)MVIEW_NAME NOT NULL VARCHAR2(30)DETAILOBJ_OWNER NOT NULL VARCHAR2(30)DETAILOBJ_NAME NOT NULL VARCHAR2(30)DETAIL_PARTITION_NAMEVARCHAR2(30)DETAIL_PARTITION_POSITIONNUMBERFRESHNESSCHAR(5)The ALL_ MVIEW_DETAIL_PARTITION view provides freshness information of each PCTdetail partition in the materialized view. Also new to Oracle Database 11g is the ALL_MVIEW_DETAIL_SUBPARTITION view. Similar to the ALL_ MVIEW_DETAIL_PARTITION view, thisview provides freshness information for each PCT detail subpartition in the materialized view.Materialized View Refresh Performance ImprovementsSeveral enhancements to the materialized view refresh mechanism are introduced in OracleDatabase 11g to reduce time and throughput. All of the enhancements are made automaticallyby Oracle. Prior to Oracle Database 11g, when a materialized view was created with a unionall, an index was not created. To take advantage of the performance implications associatedwith a fast refresh, an index needed to be created manually. Oracle Database 11g creates thisindex for you automatically. Another improvement that is available is partition change tracking formaterialized views with union all clauses. This materialized view improvement may be morenoticeable of all the materialized view improvements. During the atomic materialized view