【如何在Linux上扩展SGA超过1.7G】

       今天一台Linux服务器扩展了一下内存,达到4G,开发的人自己修改了一下SGA结果数据库无法启动了.

启动不了时,出的错误是这个样子的:
[oracle@neirong oracle]$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.4.0 - Production on Fri Nov 25 15:43:26 2005
Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.
Connected to an idle instance.
SQL> startup
ORA-27123: unable to attach to shared memory segment
Linux Error: 22: Invalid argument
Additional information: 1
Additional information: 458753
SQL> exit
Disconnected

在32位平台上,缺省的SGA最大只能扩展到1.7G,如果需要支持更大的内存,就需要降低mapped_base,重新Link Oracle软件.
俺的平台为:

[oracle@neirong bdump]$ cat /etc/redhat-release Red Hat Enterprise Linux AS release 3 (Taroon Update 2)

简单操作如下: cd $ORACLE_HOME/rdbms/lib
cp ksms.s ksms.s.bak ( if u have a ksms.s file)
genksms -s 0x12000000 > ksms.s
make -f ins_rdbms.mk ksms.o 
make -f ins_rdbms.mk ioracle

此处先备份ksms.s文件,如果编译过程中出现错误,保证操作可以被恢复:
恢复步骤大致如下:
cd $ORACLE_HOME/rdbms/lib
cp ksms.s.bak ksms.s (if u have backup ksms.s file)
genksms > ksms.s
make -f ins_rdbms.mk ksms.o
make -f ins_rdbms.mk ioracle
以下是操作日志:

[oracle@neirong dbs]$ cd $ORACLE_HOME/rdbms/lib [oracle@neirong lib]$ genksms -s 0x12000000 > ksms.s [oracle@neirong lib]$ make -f ins_rdbms.mk ksms.o [oracle@neirong lib]$ make -f ins_rdbms.mk ioracle - Linking Oracle rm -f /opt/oracle/product/9.2.0/rdbms/lib/oracle gcc -o /opt/oracle/product/9.2.0/rdbms/lib/oracle -L/opt/oracle/product/9.2.0/rdbms/lib/ -L/opt/oracle/product/9.2.0/lib/ -L/opt/oracle/product/9.2.0/lib/stubs/ -Wl,-E `test -f /opt/oracle/product/9.2.0/rdbms/lib/skgaioi.o && echo /opt/oracle/product/9.2.0/rdbms/lib/skgaioi.o` /opt/oracle/product/9.2.0/rdbms/lib/opimai.o /opt/oracle/product/9.2.0/rdbms/lib/ssoraed.o /opt/oracle/product/9.2.0/rdbms/lib/ttcsoi.o /opt/oracle/product/9.2.0/lib/nautab.o /opt/oracle/product/9.2.0/lib/naeet.o /opt/oracle/product/9.2.0/lib/naect.o /opt/oracle/product/9.2.0/lib/naedhs.o /opt/oracle/product/9.2.0/rdbms/lib/config.o -lserver9 -lodm9 -lskgxp9 -lskgxn9 -lclient9 -lvsn9 -lwtcserver9 -lcommon9 -lgeneric9 /opt/oracle/product/9.2.0/rdbms/lib/defopt.o -lknlopt `if /usr/bin/ar tv /opt/oracle/product/9.2.0/rdbms/lib/libknlopt.a | grep xsyeolap.o > /dev/null 2>&1 ; then echo "-loraolap9" ; fi` -lslax9 -lpls9 -lplp9 -lserver9 -lclient9 -lvsn9 -lwtcserver9 -lcommon9 -lgeneric9 -lknlopt -lslax9 -lpls9 -lplp9 -ljox9 -lserver9 -locijdbcst9 -lwwg9 `cat /opt/oracle/product/9.2.0/lib/ldflags` -lnsslb9 -lncrypt9 -lnsgr9 -lnzjs9 -ln9 -lnl9 -lnro9 `cat /opt/oracle/product/9.2.0/lib/ldflags` -lnsslb9 -lncrypt9 ...... mv -f /opt/oracle/product/9.2.0/bin/oracle /opt/oracle/product/9.2.0/bin/oracleO mv /opt/oracle/product/9.2.0/rdbms/lib/oracle /opt/oracle/product/9.2.0/bin/oracle chmod 6751 /opt/oracle/product/9.2.0/bin/oracle

此后数据库可以以超过1.7G的SGA区设置启动:
SQL> startup
ORACLE instance started.
Total System Global Area 2685476820 bytes
Fixed Size 454612 bytes
Variable Size 1073741824 bytes
Database Buffers 1610612736 bytes
Redo Buffers 667648 bytes
Database mounted.
Database opened.