对tom书中有一句话不怎么理解

wonder

在tom谈到：

COMPRESS/NOCOMPRESS: Both ASSM and MSSM. Enables or disables compression of
table data during either direct path operations or during conventional path
(“normal,” if you will) operations such as INSERT. Prior to Oracle 9i Release 2, this
option was not available. Starting with Oracle 9i Release 2 through Oracle 10g
Release 2, the option was COMPRESS or NOCOMPRESS, to either use or not use table
compression during direct path operations only. In those releases, only direct
path operations such as CREATE TABLE AS SELECT, INSERT /*+ APPEND */, ALTER
TABLE T MOVE, and SQL*Loader direct path loads could take advantage of
compression. Starting with Oracle 11g Release 1 and above, the options are
NOLOGGING, COMPRESS FOR OLTP, and COMPRESS BASIC. NOLOGGING disables any
compression, COMPRESS FOR OLTP enables compression for all operations (direct or
conventional path), and COMPRESS BASIC enables compression for direct path
operations only.

以上有NOLOGGING disables any compression ，意思是如果表设置为nologging属性后，指定表的压缩属性不起任何作用吗？ 谢谢！

Maclean Liu(刘相兵

这里我也不理解TOM 要真实表达的意思， 但是可以肯定 nologging 是不会禁用compression压缩的


SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0      Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production


SQL> create table compressme tablespace users nologging compress for OLTP as select * from dba_objects where 0=1;

Table created.

SQL> create table compressme1 tablespace users nologging as select * from dba_objects where 0=1;

Table created.

SQL> insert into compressme select * from dba_objects;

76275 rows created.


SQL> insert into compressme1 select * From dba_objects;

76275 rows created.

SQL> commit;

Commit complete.


  1* select segment_name ,blocks from dba_segments where segment_name like 'COMPRESSME%'
SQL>
SQL>
SQL> /

SEGMENT_NAME                       BLOCKS
------------------------------ ----------
COMPRESSME1                          1152
COMPRESSME                            512

wonder

TKS,Maclean