作業：閃回表實驗
1.構造測試表flb_test，數據不小於10000行；
TEST_USER1@PROD>create table flb_test(id number,dd date);
Table created.
TEST_USER1@PROD>begin
2 for i in 1..10000
3 loop
4 insert into flb_test values (i,sysdate+i);
5 end loop;
6 end;
7 /
PL/SQL procedure successfully completed.
exec dbms_stats.gather_table_stats('TEST_USER1','FLB_TEST');
--收集統計信息
2.查詢當前時間與scn號；
TEST_USER1@PROD>select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2014-10-13 19:23:29
TEST_USER1@PROD>select dbms_flashback.get_system_change_number from dual;
GET_SYSTEM_CHANGE_NUMBER
------------------------
1144357
3.查看該測試表block數目及大小M；
TEST_USER1@PROD>select SEGMENT_NAME,BYTES/1024/1024 size_m, BLOCKS from user_segments
2 where SEGMENT_NAME='FLB_TEST';
SEGMENT_NAME SIZE_M BLOCKS
--------------- ---------- ----------
FLB_TEST .25 32
4.在這張表的第一和第二列上，創建一個復合索引ind_flb;
TEST_USER1@PROD>create index ind_flb on flb_test(id,dd);
Index created.
5.查看該索引的葉子塊的數目以及層數；
TEST_USER1@PROD>select INDEX_NAME,STATUS ,BLEVEL,LEAF_BLOCKS from dba_indexes
2 where index_name ='IND_FLB';
INDEX_NAME STATUS BLEVEL LEAF_BLOCKS
------------------------------ -------- ---------- -----------
IND_FLB VALID 1 33
--平衡樹： 高度=層數+1
TEST_USER1@PROD>select SEGMENT_NAME,BYTES/1024/1024 size_m, BLOCKS from user_segments
2 where SEGMENT_NAME='FLB_TEST';
SEGMENT_NAME SIZE_M BLOCKS
--------------- ---------- ----------
FLB_TEST .25 32
6.刪除測試表中一半的記錄數並提交；
TEST_USER1@PROD>delete from flb_test where id<=5000;
5000 rows deleted.
TEST_USER1@PROD>commit;
Commit complete.
TEST_USER1@PROD>select count(*) from flb_test;
COUNT(*)
----------
5000
TEST_USER1@PROD>exec dbms_stats.gather_table_stats('TEST_USER1','FLB_TEST');
PL/SQL procedure successfully completed.
TEST_USER1@PROD>exec dbms_stats.gather_index_stats('TEST_USER1','IND_FLB');
PL/SQL procedure successfully completed.
--收集表和索引的統計信息
7.閃回fls_test到第二步查詢到的時間點；
TEST_USER1@PROD>select table_name ,row_movement from user_tables;
TABLE_NAME ROW_MOVE
------------------------------ --------
SALARY ENABLED
SYS_TEMP_FBT DISABLED
FLB_TEST DISABLED
EMP DISABLED
TEST_USER1@PROD>alter table flb_test enable row movement;
Table altered.
TEST_USER1@PROD>select table_name ,row_movement from user_tables;
TABLE_NAME ROW_MOVE
------------------------------ --------
EMP DISABLED
FLB_TEST ENABLED
SYS_TEMP_FBT DISABLED
SALARY ENABLED
TEST_USER1@PROD>flashback table flb_test to timestamp to_timestamp('2014-10-13 19:23:29','yyyy-mm-dd hh24:mi:ss');
Flashback complete.
TEST_USER1@PROD>exec dbms_stats.gather_table_stats('TEST_USER1','FLB_TEST');
PL/SQL procedure successfully completed.
TEST_USER1@PROD>exec dbms_stats.gather_index_stats('TEST_USER1','IND_FLB');
PL/SQL procedure successfully completed.
--收集表和索引的統計信息
--Oracle只是閃回表，所有的東西都原樣保留，應重新收集統計信息
8.查看閃回結果，以及索引狀態；
TEST_USER1@PROD>select count(*) from flb_test;
COUNT(*)
----------
10000
TEST_USER1@PROD>select INDEX_NAME,STATUS ,BLEVEL,LEAF_BLOCKS from dba_indexes
2 where index_name ='IND_FLB';
INDEX_NAME STATUS BLEVEL LEAF_BLOCKS
------------------------------ -------- ---------- -----------
IND_FLB VALID 1 33
