db_file_name_convert:对端目录,本端目录,对端目录,本端目录 log_file_name_convert:对端目录,本端目录,对端目录,本端目录 一、参数说明 [1] db_file_name_convert db_file_name_convert 主数据库和备用数据库的数据文件转换目录映射(如果两数据库的目录结构不一样),如果有多个对映,逐一指明对映关系。 格式...
index entry creation : 它不是一个问题,当你在sql语句执行计划呼叫一个全表扫描的时候,如果你看见许多针对index的db file sequential read等待。在以下例子中,TABLE_A有一个索引,db file sequential read等待是读index块到SGA来充满来自TABLE_B数据的结果。注意db file sequential read等待与db file scattered read...
DB_FILESisthe limit on the total number of files associated with a particular INSTANCE of a database. MAXDATAFILESisspecifiedinthe clause the last time CREATE DATABASE or CREATE CONTROLFILE was executed (database limit). MAXDATAFILES在最后一次执行"CREATE DATABASE 或 CREATE CONTROLFILE"的从句中...
db_file_multiblock_read_count = min(1048576/db_block_size , db_cache_size/(sessions * db_block_size)) 设置DB_FILE_MULTIBLOCK_READ_COUNT以充分利用操作系统I/O缓冲区的大小。应考虑DB_FILE_MULTIBLOCK_READ_COUNT <= 操作系统I/O缓冲区 / Oracle Block的大小,如果DB_FILE_MULTIBLOCK_READ_COUNT设置的...
PGA中有一部分内存空间是用来存放opened file descriptors,db_files参数设置越高,这部分预留空间越大。 怎么算规划这个db_files参数的值? 如果存储的大小是60T,存储大小为60*1024=61440GB 如果每次创建的数据文件是30GB(数据块为8K的情况下,32GB数据文件为最大值),那么需要创建61440/30 = 2048个数据文件,所以,...
db_file_name_convert string db_files integer 20 pdb_file_name_convert string SQL> alter session set container=highgo1; Session altered. SQL> select name from v$dbfile; NAME --- /u01/app/oracle/oradata/orcl/highgo1/system01.dbf /u01/app/oracle/oradata/orcl/highgo1/sysaux01.dbf /u01/ap...
DB_CREATE_FILE_DEST 此参数控制的是 Oracle-managed 数据库文件的路径,该路径必须事先存在。 路径必须为LVM,ASM或文件系统,不支持裸设备 语法: DB_CREATE_FILE_DEST = directory | disk group 默认值:无 可通过ALTER SESSION, ALTER SYSTEM修改该参数 ...
一. DB_FILES DB_FILES specifies the maximum number of database files that can be opened for this database. The maximum valid value is the maximum number of files, subject to operating system constraint, that will ever be specified for the database, including files to be added by ADD DATAF...
这是个隐藏参数，只有你设置了才会有，没设置都是使用默认值的。SQL> col name format a10 SQL> col value format a10 SQL> select name,value from v$parameter where name='db_files';NAME VALUE --- --- db_files 200 SQL> alter system set db_files=4000 scope=spfile ;Select *...
3. From sqlplus as sysdba, type: alter database backup controlfile to trace; 4. Type: shutdown immediate: 5. Go to the operating system and go to the USER_DUMP_DEST directory 6. Find the newest trace file 7. Edit the trace file and change MAXDATAFILES to the new value. You will ...