oracle 數據庫 lob 字段之參數 db_securefile

os: centos 7.4
db: oracle 11.2.0.4

版本

# cat /etc/centos-release
CentOS Linux release 7.4.1708 (Core) 
# 
# su - oracle
Last login: Tue Jan 21 03:40:05 CST 2020 on pts/0
$ sqlplus / as sysdba;

SQL*Plus: Release 11.2.0.4.0 Production on Mon Feb 3 10:29:09 2020

Copyright (c) 1982, 2013, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options

SQL> set lines 300;
SQL> set pages 300;
SQL> 
SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE	11.2.0.4.0	Production
TNS for Linux: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production

SQL> 

DB_SECUREFILE

SQL> show parameter securefile;

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
db_securefile			     string	 PERMITTED

在這裏插入圖片描述
Values:

NEVER

Any LOBs that are specified as SecureFiles are created as BasicFile LOBs. All SecureFile-specific storage options and features (for example, compress, encrypt, deduplicate) will cause an exception. The BasicFile LOB defaults will be used for storage options not specified.

PERMITTED

LOBs are allowed to be created as SecureFiles.

ALWAYS

Attempts to create all LOBs as SecureFile LOBs but creates any LOBs not in an Automatic Segment Space Managed tablespace as BasicFile LOBs, unless SECUREFILE is explicitly specified. Any BasicFile LOB storage options that are specified will be ignored and the SecureFile defaults will be used for all storage options not specified.

IGNORE

The SECUREFILE keyword and all SecureFile options are ignored.

If the COMPATIBLE initialization parameter is not set to 11.1.0 or higher, then LOBs are not treated as SecureFiles.

If there is a LOB column with two partitions (one that has a tablespace for which ASSM is enabled and one that has a tablespace for which ASSM is not enabled), then LOBs in the partition with the ASSM-enabled tablespace will be treated as SecureFiles and LOBs in the other partition will be treated as BasicFile LOBs.

參考:
https://docs.oracle.com/cd/E11882_01/server.112/e40402/initparams068.htm

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