使用sqlloader的直接加载方式和传统加载方式的性能差异
Direct 直接加载特点
（1）数据绕过SGA直接写入磁盘的数据文件
（2）数据直接写入高水位线HWM之后的新块，不会扫描HWM之前的空闲块
（3）commit之后移动HWM他人才能看到
（4）不对已用空间进行扫描
（5）使用direct几乎不产生redo log，不是完全不产生(安全性差)，但会产生undo数据
（6）适用OLAP在线分析场景，增 删 改不频繁的场景
Conventional传统加载特点
（1）数据先加载 -> SGA -> 磁盘的数据文件
（2）会扫描高水位线HWM之前的数据块，如果有空闲块(碎片经常DML导致)就会利用，如果没有再插入新块
（3）高水位线HWM之前的数据块是放在SGA区的
（4）会产生redo log和undo数据
（5）安全性高，可恢复数据
（6）传统加载与SQL语句insert插入没区别
1.创建一个文本数据
BYS@ bys001>set termout off;BYS@ bys001>set feedback off;
BYS@ bys001>set echo off;
BYS@ bys001>set heading off;
BYS@ bys001>set trimout on;
BYS@ bys001>set trimspool on;
BYS@ bys001>spool /home/oracle/sqlload.txt
BYS@ bys001>select owner||','||object_name||','||object_id from dba_objects;
BYS@ bys001>spool off;
此时退出SQLPLUS,到/home/oracle/ 下查看
[oracle@oel-01 ~]$ tail sqlload.txt
SCOTT,TEST_AUDIT,75940
SYS,WRH$_ACTIVE_SESSION_HISTORY,76484
SYS,WRH$_TABLESPACE_STAT,76488
BYS@ bys001>spool off;
[oracle@oel-01 ~]$ vi sqlload.txt
输入 shift + g 将光标定位到最后一行，删除BYS@ bys001>spool off; 这一行，保存退出。
[oracle@oel-01 ~]$ cat sqlload.txt | wc -l
72893
2.数据库中创建表，OS中创建SQL*LOADER的控制文件
BYS@ bys001>create table test1(owner varchar2(30),object_name varchar2(150),object_id number);Table created.
创建控制文件，内容如下
[oracle@oel-01 ~]$ cat sqlload.ctl
load data
infile '/home/oracle/sqlload.txt'
badfile '/home/oracle/sqlload_bad.txt'
discardfile '/home/oracle/sqlload_discard.txt'
append into table test1
fields terminated by ","
trailing nullcols
(owner,object_name,object_id)
3.开始加载，使用直接加载方法，用时约1秒
[oracle@oel-01 ~]$ sqlldr bys/bys control=sqlload.ctl log=sqlload.log direct=trueSQL*Loader: Release 11.2.0.1.0 - Production on Mon Jul 29 10:10:06 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
Load completed - logical record count 72893.
日志如下：
[oracle@oel-01 ~]$ cat sqlload.log
SQL*Loader: Release 11.2.0.1.0 - Production on Mon Jul 29 10:10:06 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
Control File: sqlload.ctl
Data File: /home/oracle/sqlload.txt
Bad File: /home/oracle/sqlload_bad.txt
Discard File: /home/oracle/sqlload_discard.txt
(Allow all discards)
Number to load: ALL
Number to skip: 0
Errors allowed: 50
Continuation: none specified
Path used: Direct
Table TEST1, loaded from every logical record.
Insert option in effect for this table: APPEND
TRAILING NULLCOLS option in effect
Column Name Position Len Term Encl Datatype
------------------------------ ---------- ----- ---- ---- ---------------------
OWNER FIRST * , CHARACTER
OBJECT_NAME NEXT * , CHARACTER
OBJECT_ID NEXT * , CHARACTER
Record 2: Discarded - all columns null.
Record 1: Rejected - Error on table TEST1, column OBJECT_ID.
ORA-01722: invalid number
Record 10001: Discarded - all columns null.
Record 20000: Discarded - all columns null.
Record 29999: Discarded - all columns null.
Record 39998: Discarded - all columns null.
Record 49997: Discarded - all columns null.
Record 59996: Discarded - all columns null.
Record 69995: Discarded - all columns null.
Table TEST1:
72884 Rows successfully loaded.
1 Row not loaded due to data errors.
0 Rows not loaded because all WHEN clauses were failed.
8 Rows not loaded because all fields were null.
Bind array size not used in direct path.
Column array rows : 5000
Stream buffer bytes: 256000
Read buffer bytes: 1048576
Total logical records skipped: 0
Total logical records read: 72893
Total logical records rejected: 1
Total logical records discarded: 8
Total stream buffers loaded by SQL*Loader main thread: 16
Total stream buffers loaded by SQL*Loader load thread: 0
Run began on Mon Jul 29 10:10:06 2013
Run ended on Mon Jul 29 10:10:07 2013
Elapsed time was: 00:00:00.99
CPU time was: 00:00:00.12
用时约1秒
4.使用传统加载方法：用时3秒
[oracle@oel-01 ~]$ echo 1>sqlload.log在SQLPLUS中删除表中数据。
BYS@ bys001>select count(*) from test1;
COUNT(*)
----------
72884
BYS@ bys001>truncate table test1;
[oracle@oel-01 ~]$ sqlldr bys/bys control=sqlload.ctl log=sqlload.log
在SQLPLUS中查看：
BYS@ bys001>select count(*) from test1;
COUNT(*)
----------
72884
[oracle@oel-01 ~]$ cat sqlload.log
SQL*Loader: Release 11.2.0.1.0 - Production on Mon Jul 29 10:12:17 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
Control File: sqlload.ctl
Data File: /home/oracle/sqlload.txt
Bad File: /home/oracle/sqlload_bad.txt
Discard File: /home/oracle/sqlload_discard.txt
(Allow all discards)
Number to load: ALL
Number to skip: 0
Errors allowed: 50
Bind array: 64 rows, maximum of 256000 bytes
Continuation: none specified
Path used: Conventional
Table TEST1, loaded from every logical record.
Insert option in effect for this table: APPEND
TRAILING NULLCOLS option in effect
Column Name Position Len Term Encl Datatype
------------------------------ ---------- ----- ---- ---- ---------------------
OWNER FIRST * , CHARACTER
OBJECT_NAME NEXT * , CHARACTER
OBJECT_ID NEXT * , CHARACTER
Record 2: Discarded - all columns null.
Record 1: Rejected - Error on table TEST1, column OBJECT_ID.
ORA-01722: invalid number
Record 10001: Discarded - all columns null.
Record 20000: Discarded - all columns null.
Record 29999: Discarded - all columns null.
Record 39998: Discarded - all columns null.
Record 49997: Discarded - all columns null.
Record 59996: Discarded - all columns null.
Record 69995: Discarded - all columns null.
Table TEST1:
72884 Rows successfully loaded.
1 Row not loaded due to data errors.
0 Rows not loaded because all WHEN clauses were failed.
8 Rows not loaded because all fields were null.
Space allocated for bind array: 49536 bytes(64 rows)
Read buffer bytes: 1048576
Total logical records skipped: 0
Total logical records read: 72893
Total logical records rejected: 1
Total logical records discarded: 8
Run began on Mon Jul 29 10:12:17 2013
Run ended on Mon Jul 29 10:12:20 2013
Elapsed time was: 00:00:02.97
CPU time was: 00:00:00.35