(2)、If the clustering factor is low,then Oracle Database performs a relatively low number of I/Os during a large index range scan.The index keys in arange tend to point to the same data blcok,so the database does not have to read and reread the same blocks over and over. ---当cl...
(2)If the clustering factor is low, then Oracle Database performs a relativelyl ow number of I/Os during a large index range scan. The index keys in arange tend to point to the same data block, so the database does not have to read and reread the same blocks over and over. --当...
*/SQL>createtabletmp_cfasselectceil(dbms_random.value*1000) id,'a'namefromdualconnectbyrownum<=1000;Tablecreated./* 在ID列上创建索引 */SQL>createindex ind_idontmp_cf(id); Index created./* 收集统计信息 */SQL>execdbms_stats.gather_table_stats('demo','tmp_cf'); PL/SQLproceduresuccessfull...
However, modern application requirements in terms of query response time, query throughput, database sizes, database maintenance and database interactivity capabilities on the one hand, and the manifold features of modern DBMS for physical schema design such as numerous different index structures, ...
SQL> select dbms_metadata.get_ddl('INDEX','MFGLINEENTRY2')from dual; DBMS_METADATA.GET_DDL('INDEX', --- CREATE INDEX "MESW"."MFGLINEENTRY2"ON "MESW"."MFGLINEENTRY" ("MFGLINEID", "PRIORITY") PCTFREE 10 INITRANS 2 MAXTRANS 255 NOLOGGING COMPUTESTATISTICS STORAGE(INITIAL 1048576 NEXT...
Index created Executed in 17.515 seconds SQL> exec dbms_stats.gather_table_stats(user,'T',cascade => true); PL/SQL procedure successfully completed Executed in 21.29 seconds 其索引的字典信息。 SQL> select owner, segment_name, segment_type,blocks, extents, bytes from dba_segments where wner=...
3for i in 1..5 loop 4insert into test31 select * from dba_objects order by owner; 5commit; 6end loop; 7end; 8/ PL/SQL procedure successfully completed SQL> create index index_test31 on test31(object_id); Index created SQL> execute dbms_stats.gather_table_stats('ashuang','test31...
execute dbms_stats.gather_table_stats(ownname => 'sys',tabname => 'TEST10',cascade => true); SQL> select BLOCKS from dba_tables where table_name='TEST10'; BLOCKS --- 46 SQL> select dba_indexes.clustering_factor from dba_indexes where dba_indexes.index_name='TEST10_IND'; CLUSTERING_...
3.The method of claim 1, wherein the simulating step comprises:increasing clustering on the record identifier based indexes, wherein a first column key of the record identifier indexes is used as a clustering index and an underlying database table of the record identifier based indexes is large...
In the next few years, 3D data is expected to be an intrinsic part of geospatial data. However, issues on 3D spatial data management are still in the research stage. One of the issues is performance deterioration during 3D data retrieval. Thus, a practical 3D index structure is required ...