append the test increases nologging

Jul 2 posted in Oracle (RSS), 99 views.

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Under normal circumstances
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Table space for the remaining 0.71 G

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Normal to create the test table
create table test as select * from tttttt where 0 = 1;

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Record of the current session's redo size
select s.SID, s.VALUE
from v $ sesstat s, v $ statname t
where s.sid = 16
and s.STATISTIC # = t.STATISTIC #
and t.name = 'redo size'
6 *
SQL> /

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SID VALUE
---------- ----------
10 80712300

Insert 5 million to start data

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insert into test select * from tttttt where rownum <= 50000

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Elapsed: 00:00:17.27

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Record of the current redo size

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1 select s.SID, s.VALUE
2 from v $ sesstat s, v $ statname t
3 where s.sid = 10
4 and s.STATISTIC # = t.STATISTIC #
5 and t.name = 'redo size'
6 *
SQL> /

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SID VALUE
---------- ----------
10 160754480

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Table space remaining 0.622802734375

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Summary of time: 17 stopwatch space: 0.71-0.62 = 0.09G
redo generated :160754480-80712300 = 80042180

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create table nologging

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Table space remaining 0.716552734375

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create table test nologging as select * from tttttt where 0 = 1;

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1 select s.SID, s.VALUE
2 from v $ sesstat s, v $ statname t
3 where s.sid = 10
4 and s.STATISTIC # = t.STATISTIC #
5 and t.name = 'redo size'
6 *
SQL> /

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SID VALUE
---------- ----------
10 161388232

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Insert 5 million to start data

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SQL> insert into test select * from tttttt where rownum <= 50000;

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50000 rows created.

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Elapsed: 00:00:17.34

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After the implementation of the redo

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SQL> l
1 select s.SID, s.VALUE
2 from v $ sesstat s, v $ statname t
3 where s.sid = 10
4 and s.STATISTIC # = t.STATISTIC #
5 and t.name = 'redo size'
6 *
SQL> /

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SID VALUE
---------- ----------
10 241385848

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Table space remaining 0.622802734375

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Summary of time: 17 stopwatch space: 0.71-0.62 = 0.09G
redo generated :241385848-161388232 = 79997616

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nologging way to build tables, and then used to insert append mode

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Table space remaining 0.71649169921875

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create table test nologging as select * from tttttt where 0 = 1;

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Record of the current redo size
1 select s.SID, s.VALUE
2 from v $ sesstat s, v $ statname t
3 where s.sid = 10
4 and s.STATISTIC # = t.STATISTIC #
5 and t.name = 'redo size'
6 *
SQL> /

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SID VALUE
---------- ----------
10 242019668

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Insert the beginning of the way to append data 50000
SQL> insert / * + append * / into test select * from tttttt where rownum <= 50000;

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50000 rows created.

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Elapsed: 00:00:08.31

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After the implementation of the redo
1 select s.SID, s.VALUE
2 from v $ sesstat s, v $ statname t
3 where s.sid = 10
4 and s.STATISTIC # = t.STATISTIC #
5 and t.name = 'redo size'
6 *
SQL> /

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SID VALUE
---------- ----------
10 242257132

Table space remaining 0.614990234375

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Summary of time: 8 stopwatch space: 0.71-0.61 = 0.1G
redo generated :242257132-242019668 = 237464

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Summed up under the test, or table nologging normal mode, the speed and redo of the insert does not have a fundamental impact, basically the same space occupied by

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Only used together with the insert table nologging prompted the use of append, the speed can increase, and will redo the emergence of much lower than the first two cases, however, take up some storage space and more!

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