11g中_serial_direct_read是动态参数，可以在线修改

[oracle@rhel63single ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.4.0 Production on Sun Apr 26 13:54:56 2015 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, OLAP, Data Mining and Real Application Testing options SQL> alter system set "_serial_direct_read" = false sid = '*'; System altered. SQL> show parameter serial NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ _serial_direct_read string FALSE serial_reuse string disable SQL> show parameter pfile NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ spfile string /u02/app/oracle/product/11.2.0 .4/db_1/dbs/spfiletest.ora SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> startup ORACLE instance started. Total System Global Area 1068937216 bytes Fixed Size 2260088 bytes Variable Size 612369288 bytes Database Buffers 448790528 bytes Redo Buffers 5517312 bytes Database mounted. Database opened. SQL> show parameter serial NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ _serial_direct_read string FALSE serial_reuse string disable SQL> select x.ksppinm, y.ksppstvl 2 from x$ksppi x , x$ksppcv y 3 where x.indx = y.indx 4 and x.ksppinm like '_serial_direct_read' 5 order by x.ksppinm; KSPPINM -------------------------------------------------------------------------------- KSPPSTVL -------------------------------------------------------------------------------- _serial_direct_read FALSE