The key idea consists in constructing a decision tree, within the DBMS, using bitmap indices. Indeed bitmap indices have many useful properties such as the count and bit-wise operations. We will show that these
DBMS_SPACE.CREATE_INDEX_COST ( ddl IN VARCHAR2, used_bytes OUT NUMBER, alloc_bytes OUT NUMBER, plan_table IN VARCHAR2 DEFAULT NULL); 1. 2. 3. 4. 5. Usage Notes The table on which the index is created must already exist. The computation of the index size depends on statistics gather...
SQL> create index ind_t2 on t2(object_id); Index created. 收集统计信息: BEGIN DBMS_STATS.GATHER_TABLE_STATS(ownname => 'scott', tabname => 't1', estimate_percent =>100, method_opt => 'for all columns size 1', degree => 8, cascade=>TRUE ); END; BEGIN DBMS_STATS.GATHER_TABLE...
Create table test_normal (empno number(10), ename varchar2(30), sal number(10)); Begin For i in 1..1000000 Loop Insert into test_normal values(i, dbms_random.string('U',30), dbms_random.value(1000,7000)); If mod(i, 10000) = 0 then Commit; End if; End loop; End; / Create...
For i in 1..1000000 Loop Insert into emp_normal values(i, dbms_random.string('U',30), dbms_random.value(1000,7000)); If mod(i, 10000) = 0 then Commit; End if; End loop; 10 End; 11 / PL/SQL 过程已成功完成。 SQL> create table emp_random as select /* +append */ * from ...
SQL>dropindexnormal_gender_bmx; 索引已删除。 SQL>createindexnormal_gender_idxontest_normal(gender); 索引已创建。 SQL>selectsubstr(segment_name,1,30) segment_name, bytes/1024/1024 "SizeinMB" 2fromuser_segments 3wheresegment_namein('TEST_NORMAL','NORMAL_GENDER_IDX'); ...
“Unable to enlist in the transaction” with Oracle linked server from MS SQL Server [<Name of Missing Index, sysname,>] in non clustered index [Execute SQL Task] Error: The value type (__ComObject) can only be converted to variables of type Object. [ODBC Driver Manager] Data source...
[8]. More recently, various DBMS vendors, including Oracle, Red- Brick, and Sybase, have introduced bitmap indexes into their prod- ucts to meet the performance requirements of DSS applications [5, 6]. In its simplest form, a bitmap index on an indexed attribute ...
By introducing a manual unnest in the original client code I avoided the bitmap conversion to rowid, and the query executed much more efficiently. As you can see the optimizer has predicted the 1M rowids in the inline view, but used only the key values from the 600 index entries. In the...
ORA-06512: at "SYS.DBMS_SPACE_ADMIN", line 322 ORA-06512: at line 1 --这样直接操作不行。 SYS@book> alter database datafile 6 offline ; Database altered. SYS@book> recover datafile 6; Media recovery complete. 4.修复看看: --建立一个相同大小的数据文件对应的表空间: ...