一句话描述12.1新特性(一)

12.1从推出到现在有2年了，也推出了很多新特性，下面通过简短的一句话来概括这些特性。

A.DMU取代了CSSCAN and CSALTER

在12c之前dmu默认是没有安装的，12c已经把她囊括到自己麾下

[oracle@db1 121]$ cd /u01/oracle/product/121/dmu/
[oracle@db1 dmu]$ ls -l
total 132
drwxr-xr-x 9 oracle oinstall  4096 Mar  9 23:38 dmu
-rwxr-xr-x 1 oracle oinstall 32768 Dec 23  2012 dmu32.exe
-rwxr-xr-x 1 oracle oinstall 18432 Dec 23  2012 dmu64.exe
-rwxr-xr-x 1 oracle oinstall    53 Jul 19  2012 dmu.sh
-rwxr-xr-x 1 oracle oinstall 32768 Dec 23  2012 dmuW32.exe
-rwxr-xr-x 1 oracle oinstall 18432 Dec 23  2012 dmuW64.exe
drwxr-xr-x 7 oracle oinstall  4096 Mar  9 23:38 ide
drwxr-xr-x 2 oracle oinstall  4096 Mar  9 23:39 jlib
drwxr-xr-x 8 oracle oinstall  4096 Mar  9 23:39 modules
drwxr-xr-x 3 oracle oinstall  4096 Mar  9 23:38 sleepycat
drwxr-xr-x 2 oracle oinstall  4096 Mar  9 23:39 timingframework
[oracle@db1 dmu]$

SQL> with
function get_domain(url varchar2) return varchar2 is
 2    3     pos binary_integer;
 4     len binary_integer;
 5   begin
 6     pos := instr(url, 'www.');
 7     len := instr(substr(url, pos + 4), '.') - 1;
 8     return substr(url, pos + 4, len);
 9   end;
10  select get_domain('www.ohsdba.cn') from dual
11  /

GET_DOMAIN('WWW.OHSDBA.CN')
--------------------------------------------------------------------------------
ohsdba

SQL>

[oracle@db1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 12.1.0.2.0 Production on Fri Jul 15 11:43:34 2016

Copyright (c) 1982, 2014, Oracle.  All rights reserved.

Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL>
SQL> create table t1 (c1 number generated by default on null as identity, c2 varchar2(10));

Table created.

SQL>
SQL> desc t1
Name                                      Null?    Type
----------------------------------------- -------- ----------------------------
C1                                        NOT NULL NUMBER
C2                                                 VARCHAR2(10)

SQL> insert into t1(c2) values('robin');

1 row created.

SQL> c/robin/han
 1* insert into t1(c2) values('han')
SQL> /

1 row created.

SQL> c/han/ohsdba
 1* insert into t1(c2) values('ohsdba')
SQL> /

1 row created.

SQL> commit;

Commit complete.

SQL> select * from t1;

       C1 C2
---------- ----------
        1 robin
        2 han
        3 ohsdba

SQL>

D.分区表的增强

Global Index Maintenance for DROP and TRUNCATE Partition
当Drop或Truncate分区时，全局索引的维护可以避开高峰期延迟删除

Cascade Functionality for TRUNCATE and EXCHANGE Partition
当Truncate或Exchange分区时，对Reference-partitioned表，在父表上的的操作，字表会继承，简化了DBA的操作

ONLINE Move Partition
在线移动分区在操作期间，DML的操作正常进行，不用担心被中断，全局索引会自动维护，无须手动重建

Interval Reference Partitioning
一种新的满足业务需求而增加的新分区类型，维护更方便

Partial Indexes for Partitioned Tables
本地索引和全局索引可以在表的部分分区上创建
http://docs.oracle.com/database/121/VLDBG/GUID-256BA7EE-BF49-42DE-9B38-CD2480A73129.htm#VLDBG14102

E.Performance方面

Adaptive Query Optimization

http://docs.oracle.com/database/121/TGSQL/tgsql_astat.htm#GUID-E1F39134-24F1-4EF7-B614-82F9428CA762

SET LINES 200 PAGES 0
SET LONG 100000
COLUMN REPORT FORMAT A200
SQL> SET LINES 200 PAGES 0
SQL> SET LONG 100000
SQL> COLUMN REPORT FORMAT A200
SQL>
SQL> VARIABLE my_report CLOB;
SQL> BEGIN
 2    :my_report :=DBMS_STATS.REPORT_GATHER_SCHEMA_STATS(
 3      ownname      => 'SYS'       ,
 4      detail_level => 'TYPICAL'  ,
 5      format       => 'HTML'     );
 6  END;
 7  /

PL/SQL procedure successfully completed.

SQL>

Database Smart Flash Cache Support for Multiple Flash Devices

SQL> exec DBMS_STATS.GATHER_SYSTEM_STATS('EXADATA');
PL/SQL procedure successfully completed.

SQL> select distinct histogram from dba_tab_col_statistics;
HISTOGRAM
---------------
FREQUENCY
HYBRID
TOP-FREQUENCY
NONE
SQL>

Online Statistics Gathering for Bulk Loads