This document discusses direct-path inserts in Oracle and how they affect performance, table size, and redo generation. Direct-path inserts append new rows to the end of the table without using the buffer cache, which can increase table size even with free space. Redo generation depends on the combination of table logging mode, insert mode (append or not), and archivelog mode. The document provides examples demonstrating the different combinations.

1. 鄭 鎮健 (Jingun Jung)
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0.9 : 2014/1/16, 新規作成
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3. 
Append Hint
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Affect Performance
Affect the Table Size
Affect Redo Generation 1, 2, 3
Website
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Data is appended to the end of the table, rather
attempting to use existing free space within the
table.
Data is written directly to the data files, by
passing the buffer cache.
Referential integrity constraints are ignored.
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5. As direct-path inserts append data to the end of
the table, they constantly increase the table high
water mark, even if there is lots of free space
within the table.
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6. Table Mode
Insert Mode
ArchiveLog
Mode
Result
LOGGING
APPEND
Archive Log
Redo Generated
NOLOGGING
APPEND
Archive Log
No Redo
LOGGING
NO APPEND
Archive Log
Redo Generated
NOLOGGING
NO APPEND
Archive Log
Redo Generated
LOGGING
APPEND
No Archive Log
No Redo
NOLOGGING
APPEND
No Archive Log
No Redo
LOGGING
NO APPEND
No Archive Log
Redo Generated
NOLOGGING
NO APPEND
No Archive Log
Redo Generated
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7. SQL> CREATE TABLE t1 AS SELECT * FROM all_objects WHERE 1=2;
SQL> archive log list;
Database log mode
No Archive Mode
Automatic archival
Disabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
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Current log sequence
9
SQL> SET AUTOTRACE ON STATISTICS
SQL> INSERT INTO t1 SELECT * FROM all_objects;
55671 rows created.
Statistics
---------------------------------------------------------3077 recursive calls
8127 db block gets
64112 consistent gets
6 physical reads
6608264 redo size
830 bytes sent via SQL*Net to client
796 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1529 sorts (memory)
0 sorts (disk)
55671 rows processed
SQL> COMMIT;
Commit complete.
SQL> DROP TABLE t1 PURGE;
SQL> CREATE TABLE t1 AS SELECT * FROM all_objects WHERE 1=2;
SQL> archive log list;
Database log mode
No Archive Mode
Automatic archival
Disabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
7
Current log sequence
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SQL> SET AUTOTRACE ON STATISTICS
SQL> INSERT /*+ APPEND */ INTO t1 SELECT * FROM all_objects;
55671 rows created.
Statistics
---------------------------------------------------------849 recursive calls
1418 db block gets
60376 consistent gets
2 physical reads
51360 redo size
820 bytes sent via SQL*Net to client
810 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1491 sorts (memory)
0 sorts (disk)
55671 rows processed
SQL> COMMIT;
Commit complete.
SQL> DROP TABLE t1 PURGE;
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8. SQL> CREATE TABLE t1 AS SELECT * FROM all_objects WHERE 1=2;
SQL> archive log list;
Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
8
Next log sequence to archive
10
Current log sequence
10
SQL> SET AUTOTRACE ON STATISTICS
SQL> INSERT INTO t1 SELECT * FROM all_objects;
55671 rows created.
Statistics
---------------------------------------------------------3378 recursive calls
7930 db block gets
62636 consistent gets
318 physical reads
6594052 redo size
832 bytes sent via SQL*Net to client
796 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1553 sorts (memory)
0 sorts (disk)
55671 rows processed
SQL> COMMIT;
Commit complete.
SQL> DROP TABLE t1 PURGE;
SQL> CREATE TABLE t1 AS SELECT * FROM all_objects WHERE 1=2;
SQL> archive log list;
Database log mode
Archive Mode
Automatic archival
Enable
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
8
Next log sequence to archive
10
Current log sequence
10
SQL> SET AUTOTRACE ON STATISTICS
SQL> INSERT /*+ APPEND */ INTO t1 SELECT * FROM all_objects;
55671 rows created.
Statistics
---------------------------------------------------------1146 recursive calls
1417 db block gets
60536 consistent gets
71 physical reads
6656776 redo size
823 bytes sent via SQL*Net to client
810 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1494 sorts (memory)
0 sorts (disk)
55671 rows processed
SQL> COMMIT;
Commit complete.
SQL> DROP TABLE t1 PURGE;
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9. SQL> CREATE TABLE t1 AS SELECT * FROM all_objects WHERE 1=2;
SQL> archive log list;
Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
8
Next log sequence to archive 10
Current log sequence
10
SQL> ALTER TABLE t1 NOLOGGING;
Table altered.
SQL> SET AUTOTRACE ON STATISTICS
SQL> INSERT INTO t1 SELECT * FROM all_objects;
55671 rows created.
Statistics
---------------------------------------------------------1097 recursive calls
7969 db block gets
61504 consistent gets
3 physical reads
6595468 redo size
839 bytes sent via SQL*Net to client
796 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1499 sorts (memory)
0 sorts (disk)
55671 rows processed
SQL> COMMIT;
Commit complete.
SQL> DROP TABLE t1 PURGE;
SQL> CREATE TABLE t1 AS SELECT * FROM all_objects WHERE 1=2;
SQL> archive log list;
Database log mode
Archive Mode
Automatic archival
Enable
Archive destination
USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence
8
Next log sequence to archive
10
Current log sequence
10
SQL> ALTER TABLE t1 NOLOGGING;
Table altered.
SQL> SET AUTOTRACE ON STATISTICS
SQL> INSERT /*+ APPEND */ INTO t1 SELECT * FROM all_objects;
55671 rows created.
Statistics
---------------------------------------------------------845 recursive calls
1418 db block gets
60397 consistent gets
2 physical reads
51292 redo size
825 bytes sent via SQL*Net to client
810 bytes received via SQL*Net from client
3 SQL*Net roundtrips to/from client
1491 sorts (memory)
0 sorts (disk)
55671 rows processed
SQL> COMMIT;
Commit complete.
SQL> DROP TABLE t1 PURGE;
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10. English
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http://www.oracle-base.com/articles/misc/append-hint.php
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:5280714813869
http://docs.oracle.com/cd/B28359_01/server.111/b28310/archredo002.htm#i1006201
Korean
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http://www.oracleclub.com/lecture/1974
http://develop.sunshiny.co.kr/763
Japanese
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http://www.shift-the-oracle.com/inside/direct-pass-insert.html
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