今天在虛擬機中測試用alert文件來構造初始化參數文件，步驟如下：
1 找到alert文件
通常alert文件在bdump目錄下，如果不知道bdump目錄在哪，可以在sqlplus下，用命令來查看
SQL> show parameter background_dump_dest
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
background_dump_dest string /opt/oracle/admin/orcl/bdump
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拷貝日誌文件中關鍵參數文件並修改，命名爲$/ORACLE_HOME/dbs/pfileabc.ora
processes = 150
shared_pool_size = 88080384
large_pool_size = 4194304
java_pool_size = 4194304
streams_pool_size = 0
sga_target = 281018368
control_files = ('/opt/oracle/oradata/orcl/control01.ctl','/opt/oracle/oradata/orcl/control02.ctl','/opt/oracle/oradata/orcl/control03.ctl')
db_block_size = 8192
__db_cache_size = 180355072
compatible = 10.2.0.1.0
db_file_multiblock_read_count= 16
db_recovery_file_dest = '/opt/oracle//flash_recovery_area'
db_recovery_file_dest_size= 2147483648
undo_management = AUTO
undo_tablespace = UNDOTBS1
remote_login_passwordfile= EXCLUSIVE
db_domain = ''
dispatchers = '(PROTOCOL=TCP) (SERVICE=orclXDB)'
job_queue_processes = 10
background_dump_dest = '/opt/oracle/admin/orcl/bdump'
user_dump_dest = '/opt/oracle/admin/orcl/udump'
core_dump_dest = '/opt/oracle/admin/orcl/cdump'
audit_file_dest = '/opt/oracle/admin/orcl/adump'
db_name = 'orcl'
open_cursors = 300
pga_aggregate_target = 92274688
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2 關閉數據庫並用新的參數文件啓動
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup pfile=$ORACLE_HOME/dbs/pfileabc.ora
ORACLE instance started.
Total System Global Area 281018368 bytes
Fixed Size 1218968 bytes
Variable Size 96470632 bytes
Database Buffers 180355072 bytes
Redo Buffers 2973696 bytes
Database mounted.
Database opened.