CLUSTER_DATABASE

Property
Description

Parameter type
Boolean

Default value
false

Modifiable
No

Range of values
true | false

Basic
Yes

Real Application Clusters
For all instances, the value must be set to TRUE.

CLUSTER_DATABASE is a Real Application Clusters parameter that specifies whether or not Real Application Clusters is enabled.

COMPATIBLE

Property
Description

Parameter type
String

Syntax
COMPATIBLE = release_number

Default value
10.0.0

Modifiable
No

Range of values
9.2.0 to default release

Basic
Yes

Real Application Clusters
Multiple instances must have the same value.

COMPATIBLE allows you to use a new release of Oracle, while at the same time guaranteeing backward compatibility with an earlier release. This is helpful if it becomes necessary to revert to the earlier release.

This parameter specifies the release with which Oracle must maintain compatibility. It allows you to take advantage of the maintenance improvements of a new release immediately in your production systems without testing the new functionality in your environment. Some features of the release may be restricted.

此参数指定的释放与Oracle必须保持兼容性

When using a standby database, this parameter must have the same value on both the primary and standby databases.

如果用在备库上这个值必须跟主库一致

CONTROL_FILES

Property
Description

Parameter type
String

Syntax
CONTROL_FILES = filename [, filename ] ...

Note: The control file name can be an OMF (Oracle Managed Files) name. This occurs when the control file is re-created using the CREATE CONTROLFILE REUSE statement.

Default value
Operating system-dependent

Modifiable
No

Range of values
1 to 8 filenames

Basic
Yes

Real Application Clusters
Multiple instances must have the same value.

Every database has a control file, which contains entries that describe the structure of the database (such as its name, the timestamp of its creation, and the names and locations of its datafiles and redo files). CONTROL_FILES specifies one or more names of control files, separated by commas.

Oracle recommends that you multiplex multiple control files on different devices or mirror the file at the operating system level.

指定控制文件路径

DB_BLOCK_SIZE

Property
Description

Parameter type
Integer

Default value
8192

Modifiable
No

Range of values
2048 to 32768, but your operating system may have a narrower range

Basic
Yes

Real Application Clusters
You must set this parameter for every instance, and multiple instances must have the same value.

Caution:

Set this parameter at the time of database creation. Do not alter it afterward.

DB_BLOCK_SIZE specifies (in bytes) the size of Oracle database blocks. Typical values are 4096 and 8192. The value of this parameter must be a multiple of the physical block size at the device level.

The value for DB_BLOCK_SIZE in effect at the time you create the database determines the size of the blocks. The value must remain set to its initial value.

For Real Application Clusters, this parameter affects the maximum value of the FREELISTS storage parameter for tables and indexes. Oracle uses one database block for each freelist group. Decision support system (DSS) and data warehouse database environments tend to benefit from larger block size values.

DB_BLOCK_SIZE 指定了数据为患 块大小,通常值为4096和8192,这个值的大小必须物理整数倍,我理解的是操作系统块大小

DSS跟数据仓库设置大的块对数据库性能有较大的提升

DB_CREATE_FILE_DEST

Property
Description

Parameter type
String

Syntax
DB_CREATE_FILE_DEST = directory | disk group

Default value
There is no default value.

Modifiable
ALTER SESSION, ALTER SYSTEM

Basic
Yes

DB_CREATE_FILE_DEST specifies the default location for Oracle-managed datafiles. This location is also used as the default location for Oracle-managed control files and online redo logs if none of the DB_CREATE_ONLINE_LOG_DEST_n initialization parameters are specified.

指定本地oracle 自动 管理数据文件存放路径可以是本地目录也可以提磁盘组,如果没有为DB_CREATE_ONLINE_LOG_DEST_n 指定, 这个存放路径也可以存放控制文件和redo文件

If a file system directory is specified as the default location, then the directory must already exist; Oracle does not create it. The directory must have appropriate permissions that allow Oracle to create files in it. Oracle generates unique names for the files, and a file thus created is an Oracle-managed file.

如果指定了这个路径,

DB_CREATE_ONLINE_LOG_DEST_n

Property
Description

Parameter type
String

Syntax
DB_CREATE_ONLINE_LOG_DEST_[1 | 2 | 3 | 4 | 5] = directory | disk group

Default value
There is no default value.

Modifiable
ALTER SESSION, ALTER SYSTEM

Basic
Yes

DB_CREATE_ONLINE_LOG_DEST_n (where n = 1, 2, 3, ... 5) specifies the default location for Oracle-managed control files and online redo logs. If more than oneDB_CREATE_ONLINE_LOG_DEST_n parameter is specified, then the control file or online redo log is multiplexed across the locations of the otherDB_CREATE_ONLINE_LOG_DEST_n parameters. One member of each online redo log is created in each location, and one control file is created in each location.

Specifying at least two parameters provides greater fault tolerance for the control files and online redo logs if one of the locations should fail.

指定至少两个参数提供了更大的容错控制文件和联机重做日志，如果其中一个位置就失败了

If a file system directory is specified as the default location, then the directory must already exist; Oracle does not create it. The directory must have appropriate permissions that allow Oracle to create files in it. Oracle generates unique names for the files, and a file thus created is an Oracle-managed file.

DB_DOMAIN

Property
Description

Parameter type
String

Syntax
DB_DOMAIN = domain_name

Default value
There is no default value.

Modifiable
No

Range of values
Any legal string of name components, separated by periods and up to 128 characters long (including the periods). This value cannot be NULL.

Basic
Yes

Real Application Clusters
You must set this parameter for every instance, and multiple instances must have the same value.

In a distributed database system, DB_DOMAIN specifies the logical location of the database within the network structure. You should set this parameter if this database is or ever will be part of a distributed system. The value consists of the extension components of a global database name, consisting of valid identifiers (any alphanumeric ASCII characters), separated by periods. Oracle recommends that you specify DB_DOMAIN as a unique string for all databases in a domain.

This parameter allows one department to create a database without worrying that it might have the same name as a database created by another department. If one sales department‘s DB_DOMAIN is JAPAN.ACME.COM, then their SALES database (SALES.JAPAN.ACME.COM) is uniquely distinguished from another database with DB_NAME = SALES but with DB_DOMAIN = US.ACME.COM.

If you omit the domains from the name of a database link, Oracle expands the name by qualifying the database with the domain of your local database as it currently exists in the data dictionary, and then stores the link name in the data dictionary. The characters valid in a database domain name are: alphanumeric characters, underscore (_), and number sign (#).

DB_NAME

Property
Description

Parameter type
String

Syntax
DB_NAME = database_name

Default value
There is no default value.

Modifiable
No

Basic
Yes

Real Application Clusters
You must set this parameter for every instance. Multiple instances must have the same value, or the same value must be specified in the STARTUP OPEN SQL*Plus command or the ALTER DATABASE MOUNT SQL statement.

DB_NAME specifies a database identifier of up to 8 characters. This parameter must be specified and must correspond to the name specified in the CREATE DATABASE statement.

If you have multiple databases, the value of this parameter should match the Oracle instance identifier of each one to avoid confusion with other databases running on the system. The value of DB_NAME should be the same in both the standby and production initialization parameter files.

The database name specified in either the STARTUP command or the ALTER DATABASE ... MOUNT statement for each instance of the cluster database must correspond to the DB_NAME initialization parameter setting.

The following characters are valid in a database name: alphanumeric characters, underscore (_), number sign (#), and dollar sign ($). No other characters are valid. Oracle removes double quotation marks before processing the database name. Therefore you cannot use double quotation marks to embed other characters in the name. The database name is case insensitive.

DB_RECOVERY_FILE_DEST

Property
Description

Parameter type
String

Syntax
DB_RECOVERY_FILE_DEST = directory | disk group

Default value
There is no default value.

Modifiable
ALTER SYSTEM ... SID=‘*‘

Basic
Yes

Real Application Clusters
You must set this parameter for every instance, and multiple instances must have the same value.

DB_RECOVERY_FILE_DEST specifies the default location for the flash recovery area. The flash recovery area contains multiplexed copies of current control files and online redo logs, as well as archived redo logs, flashback logs, and RMAN backups.

db_recovery_file_dest指定闪回恢复区的默认位置。闪回恢复区包含复用现有的控制文件和联机重做日志，以及归档重做日志，闪回日志，及RMAN备份

Specifying this parameter without also specifying the DB_RECOVERY_FILE_DEST_SIZE initialization parameter is not allowed.

DB_RECOVERY_FILE_DEST_SIZE

Property
Description

Parameter type
Big integer

Syntax
DB_RECOVERY_FILE_DEST_SIZE = integer [K | M | G]

Default value
There is no default value.

Modifiable
ALTER SYSTEM ... SID=‘*‘

Basic
Yes

Real Application Clusters
You must set this parameter for every instance, and multiple instances must have the same value.

DB_RECOVERY_FILE_DEST_SIZE specifies (in bytes) the hard limit on the total space to be used by target database recovery files created in the flash recovery area.

DB_UNIQUE_NAME

Property
Description

Parameter type
String

Syntax
DB_UNIQUE_NAME = database_unique_name

Default value
Database instances: the value of DB_NAME

Automatic Storage Management instances: +ASM

Modifiable
No

Basic
Yes

Real Application Clusters
Multiple instances must have the same value.

DB_UNIQUE_NAME specifies a globally unique name for the database. Databases with the same DB_NAME within the same DB_DOMAIN (for example, copies of a database created for reporting or a physical standby) must have a unique DB_UNIQUE_NAME. Every database‘s DB_UNIQUE_NAME must be unique within the enterprise.

The value of DB_UNIQUE_NAME can be up to 30 characters and is case insensitive. The following characters are valid in a database name: alphanumeric characters, underscore (_), number sign (#), and dollar sign ($).

INSTANCE_NUMBER

Property
Description

Parameter type
Integer

Default value
Lowest available number; derived from instance start up order and INSTANCE_NUMBER value of other instances. If not configured for Real Application Clusters, then 0.

Modifiable
No

Range of values
1 to maximum number of instances specified when the database was created

Basic
Yes

Real Application Clusters
You must set this parameter for every instance, and all instances must have different values.

INSTANCE_NUMBER is a Real Application Clusters parameter that can be specified in parallel mode or exclusive mode. It specifies a unique number that maps the instance to one free list group for each database object created with storage parameter FREELIST GROUPS.

The INSTANCE parameter of the ALTER TABLE ... ALLOCATE EXTENT statement assigns an extent to a particular free list group. If you set INSTANCE_NUMBER to the value specified for the INSTANCE parameter, the instance uses that extent for inserts and for updates that expand rows.

The practical maximum value of this parameter is the maximum number of instances specified in the CREATE DATABASE statement. The absolute maximum is operating system-dependent.

JOB_QUEUE_PROCESSES

Property
Description

Parameter type
Integer

Default value
0

Modifiable
ALTER SYSTEM

Range of values
0 to 1000

Basic
Yes

Real Application Clusters
Multiple instances can have different values.

JOB_QUEUE_PROCESSES specifies the maximum number of processes that can be created for the execution of jobs. It specifies the number of job queue processes per instance (J000, ... J999). Replication uses job queues for data refreshes. Advanced queuing uses job queues for message propagation. You can create user job requests through the DBMS_JOB package.

job_queue_processes指定可执行的工作，创建了最大进程数。它指定的作业队列进程的每一个实例的数量（j000，…j999）。复制使用工作队列的数据刷新。高级队列使用工作队列的消息的传播。你可以通过dbms_job包创建用户的job需求。

Some job queue requests are created automatically. An example is refresh support for materialized views. If you wish to have your materialized views updated automatically, you must set JOB_QUEUE_PROCESSES to a value of one or higher.

LOG_ARCHIVE_DEST_n

Property
Description

Parameter type
String

Syntax
LOG_ARCHIVE_DEST_[1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10] =

 { null_string | { LOCATION=path_name | SERVICE=service_name } [ { MANDATORY | OPTIONAL } ] [ REOPEN[=seconds] ] [ DELAY[=minutes] ] [ NOREGISTER ] [ TEMPLATE=template] ] [ ALTERNATE=destination ] [ DEPENDENCY=destination ] [ MAX_FAILURE=count ] [ ARCH | LGWR ] [ SYNC | ASYNC ] [ AFFIRM | NOAFFIRM ] [ NET_TIMEOUT=seconds ] [ VALID_FOR=(redo_log_type,database_role) ] [ DB_UNIQUE_NAME ] [ VERIFY ] }

Default value
There is no default value.

Modifiable
Most attributes are modifiable by ALTER SESSION and ALTER SYSTEM, but some are not. See Oracle Data Guard Concepts and Administration for further information.

Basic
Yes

The LOG_ARCHIVE_DEST_n initialization parameter defines up to ten (where n = 1, 2, 3, ... 10) destinations, each of which must specify either the LOCATION or theSERVICE attribute to specify where to archive the redo data. All other attributes are optional. Note that whether you are specifying the LOCATION attribute or theSERVICE attribute, it must be the first attribute supplied in the list of attributes.

该log_archive_dest_n初始化参数定义最高为10（n＝1，2，3，…10）目的地，每个都必须指定位置或服务属性指定在归档的重做数据。其他所有属性都是可选的。值得注意的是，你是否在指定本地属性和服务属性，它必须在属性列表中提供的第一个属性。

If you choose not to enter any attributes, you can specify a null string by entering the following:

LOG_ARCHIVE_DEST_n=‘ ‘;

You set the attributes for the LOG_ARCHIVE_DEST_n initialization parameter to control different aspects of how redo transport services transfer redo data from a production or primary database destination to another (standby) database destination. You can query the V$ARCHIVE_DEST view to see the current attribute settings for each destination (n).

你设置的属性为log_archive_dest_n初始化参数控制不同方面如何传输服务传输重做数据从生产或主数据库的目的地到另一个（备用）数据库的目的地。你可以查询V$ archive_dest视图来查看当前属性设置为每个目的地（N）。

LOG_ARCHIVE_DEST_STATE_n

Property
Description

Parameter type
String

Syntax
LOG_ARCHIVE_DEST_STATE_n = { alternate | reset | defer | enable }

Default value
enable

Modifiable
ALTER SESSION, ALTER SYSTEM

Basic
Yes

The LOG_ARCHIVE_DEST_STATE_n parameters (where n = 1, 2, 3, ... 10) specify the availability state of the corresponding destination. The parameter suffix (1 through 10) specifies one of the ten corresponding LOG_ARCHIVE_DEST_n destination parameters.

该log_archive_dest_state_n参数（n = 1，2，3，…10）指定相应的目的地的可用性状态。参数的后缀（1到10）指定一个相应的10个log_archive_dest_n目标参数。

Values:

• enabled

  Specifies that a valid log archive destination can be used for a subsequent archiving operation (automatic or manual). This is the default.

  指定一个有效的归档日志的目的地可用于随后的归档操作（自动或手动）。这个是默认的。

• defer

  Specifies that valid destination information and attributes are preserved, but the destination is excluded from archiving operations until re-enabled.

  指定有效的目标信息和属性将被保留，但目标是排除归档操作直到重新启用。

• alternate

  Specifies that a log archive destination is not enabled but will become enabled if communications to another destination fail.

指定一个日志归档的目的地是未启用，但是另外一个归档目的地通讯失败将会启用

The LOG_ARCHIVE_DEST_STATE_n parameters have no effect on the ENABLE state for the LOG_ARCHIVE_DEST or LOG_ARCHIVE_DUPLEX_DEST parameters.

该log_archive_dest_state_n参数对用于log_archive_dest或log_archive_duplex_dest参数的状态没有影响。

The V$ARCHIVE_DEST dynamic performance view shows values in use for the current session. The DEST_ID column of that view corresponds to the archive destination suffix n

NLS_LANGUAGE

Property
Description

Parameter type
String

Syntax
NLS_LANGUAGE = language

Default value
Operating system-dependent, derived from the NLS_LANG environment variable

Modifiable
ALTER SESSION

Range of values
Any valid language name

Basic
Yes

NLS_LANGUAGE specifies the default language of the database. This language is used for messages, day and month names, symbols for AD, BC, a.m., and p.m., and the default sorting mechanism. This parameter also determines the default values of the parameters NLS_DATE_LANGUAGE and NLS_SORT.

nls_language指定数据库的默认语言。这一语言是用于信息，日期和月份的名称，符号，广告，BC，上午和下午，，和默认的排序机制。此参数确定的参数nls_date_language和nls_sor默认值

nls_lang可以是American_America.zhs16gbk

通过alter system set nls_language=‘AMERICAN‘ scope=spfile; 可以更改nls_database_parameters和nls_instance_parameters的nls_language

通过alter session set nls_language=‘SIMPLIFIED CHINESE‘; 可以更改nls_session_parameters的nls_language

PGA_AGGREGATE_TARGET

Property
Description

Parameter type
Big integer

Syntax
PGA_AGGREGATE_TARGET = integer [K | M | G]

Default value
10 MB or 20% of the size of the SGA, whichever is greater

Modifiable
ALTER SYSTEM

Range of values
Minimum: 10 MB

Maximum: 4096 GB - 1

Basic
Yes

PGA_AGGREGATE_TARGET specifies the target aggregate PGA memory available to all server processes attached to the instance.

pga_aggregate_target指定目标总的PGA内存提供给所有服务器进程连接到实例。

Setting PGA_AGGREGATE_TARGET to a nonzero value has the effect of automatically setting the WORKAREA_SIZE_POLICY parameter to AUTO. This means that SQL working areas used by memory-intensive SQL operators (such as sort, group-by, hash-join, bitmap merge, and bitmap create) will be automatically sized. A nonzero value for this parameter is the default since, unless you specify otherwise, Oracle sets it to 20% of the SGA or 10 MB, whichever is greater.

设置pga_aggregate_target为非零的值有影响workarea_size_policy参数自动设置为自动。这意味着 SQL working的内存（如排序，组，哈希连接，位图合并，和位图的大小会自动创建）。由于该参数的一个非零的值是默认的，除非你另有指定，Oracle将其设置为20%或10 MB的SGA，以较高者为准。

Setting PGA_AGGREGATE_TARGET to 0 automatically sets the WORKAREA_SIZE_POLICY parameter to MANUAL. This means that SQL workareas are sized using the*_AREA_SIZE parameters.

如果将PGA_AGGREGATE_TARGET设置为0将自动设置 WORKAREA_SIZE_POLICY参数为手动.这就意味着 SQL workareas

使用设置大小,例如你设置sort area 为10M那么大小就为10M

Oracle attempts to keep the amount of private memory below the target specified by this parameter by adapting the size of the work areas to private memory. When increasing the value of this parameter, you indirectly increase the memory allotted to work areas. Consequently, more memory-intensive operations are able to run fully in memory and less will work their way over to disk.

Oracle试图保持私有内存低于目标指定此参数的工作领域的私有内存量大小。当增加这个参数的值，你间接增加内存分配的工作区。因此，更多的内存密集型操作，可以运行完全在内存中不将他们的工作方式到磁盘。

When setting this parameter, you should examine the total memory on your system that is available to the Oracle instance and subtract the SGA. You can assign the remaining memory to PGA_AGGREGATE_TARGET..

设置此参数时，你应该检查你的系统是可用的Oracle实例SGA的内存总量减去。你可以把剩余的内存pga_aggregate_target ..

PROCESSES

Property
Description

Parameter type
Integer

Default value
40 to operating system-dependent

Modifiable
No

Range of values
6 to operating system dependent

Basic
Yes

Real Application Clusters
Multiple instances can have different values.

PROCESSES specifies the maximum number of operating system user processes that can simultaneously connect to Oracle. Its value should allow for all background processes such as locks, job queue processes, and parallel execution processes.

处理指定可以同时连接到Oracle最大的操作系统用户进程数。它的值应该允许所有的后台进程，如锁，作业队列进程，和并行执行的过程。

The default values of the SESSIONS and TRANSACTIONS parameters are derived from this parameter. Therefore, if you change the value of PROCESSES, you should evaluate whether to adjust the values of those derived parameters.

默认值的ESSIONS and TRANSACTIONS参数均来自这个参数。因此，如果你改变程序的价值，你应该评估是否要调整这些参数的值。

REMOTE_LISTENER

Property
Description

Parameter type
String

Syntax
REMOTE_LISTENER = network_name

Default value
There is no default value.

Modifiable
ALTER SYSTEM

Basic
Yes

REMOTE_LISTENER specifies a network name that resolves to an address or address list of Oracle Net remote listeners (that is, listeners that are not running on the same machine as this instance). The address or address list is specified in the TNSNAMES.ORA file or other address repository as configured for your system.

REMOTE_LOGIN_PASSWORDFILE

Property
Description

Parameter type
String

Syntax
REMOTE_LOGIN_PASSWORDFILE=

{NONE | SHARED}

Default value
SHARED

Modifiable
No

Basic
Yes

Real Application Clusters
Multiple instances must have the same value.

REMOTE_LOGIN_PASSWORDFILE specifies whether Oracle checks for a password file.

REMOTE_LOGIN_PASSWORDFILE 指定决定oracle是否检查密码文件

Values:

• NONE

  Oracle ignores any password file. Therefore, privileged users must be authenticated by the operating system.

  参数值为NONE oracle 是忽略任何密码文件,因此，特权用户必须由操作系统验证。

• SHARED

  One or more databases can use the password file. The password file can contain SYS as well as non-SYS users.

  参数值为share

  一个或多个数据库，可以使用密码文件。密码文件可以包含系统以及非系统用户。这个是默认值

  ROLLBACK_SEGMENTS

  Property
  Description

  Parameter type
  String

  Syntax
  ROLLBACK_SEGMENTS =

  (segment_name [, segment_name] ... )

  Default value
  If you do not specify this parameter, the instance uses public rollback segments by default, unless the UNDO_MANAGEMENTinitialization parameter is set to AUTO. In that case, the ROLLBACK_SEGMENTS parameter is ignored and automatic undo management is used.

  Modifiable
  No

  Range of values
  Any rollback segment names listed in DBA_ROLLBACK_SEGS except SYSTEM

  Basic
  Yes

  Real Application Clusters
  Multiple instances must have different values.

  ROLLBACK_SEGMENTS allocates one or more rollback segments by name to this instance. If you set this parameter, the instance acquires all of the rollback segments named in this parameter, even if the number of rollback segments exceeds the minimum number required by the instance (calculated asTRANSACTIONS / TRANSACTIONS_PER_ROLLBACK_SEGMENT).

  ROLLBACK_SEGMENTS 通过名字分配一个或更多的回滚段给实例,实例获取所有的回滚段在这个参数命名，即使回滚段的数目超过由实例所需的最小数目（计算astransactions / transactions_per_rollback_segment）。

  You cannot change the value of this parameter dynamically, but you can change its value and then restart the instance. Although this parameter usually specifies private rollback segments, it can also specify public rollback segments if they are not already in use.

  To find the name, segment ID number, and status of each rollback segment in the database, query the data dictionary view DBA_ROLLBACK_SEGS.

  你不能动态地改变该参数的值，但你可以改变它的值，然后重新启动实例。虽然这个参数通常指定私人的回滚段，它也可以让他们在没有指定使用公共的回滚段。

  When UNDO_MANAGEMENT is set to AUTO, ROLLBACK_SEGMENTS is ignored.

  如果将UNDO_MANAGEMENT 设置autoROLLBACK_SEGMENTS 将被忽略

  SESSIONS

  Property
  Description

  Parameter type
  Integer

  Default value
  Derived: (1.1 * PROCESSES) + 5

  Modifiable
  No

  Range of values
  1 to 2³¹

  Basic
  Yes

  SESSIONS specifies the maximum number of sessions that can be created in the system. Because every login requires a session, this parameter effectively determines the maximum number of concurrent users in the system. You should always set this parameter explicitly to a value equivalent to your estimate of the maximum number of concurrent users, plus the number of background processes, plus approximately 10% for recursive sessions.

  会话指定可以在系统中创建的最大会话数。因为每个登录需要会话，此参数有效地确定系统中的最大并发用户数。你应该将此参数设置明确的价值相当于你的最大并发用户数，加上后的进程数，再加上约10%的递归会话。

  Oracle uses the default value of this parameter as its minimum. Values between 1 and the default do not trigger errors, but Oracle ignores them and uses the default instead.

  Oracle使用此参数的默认值为最小。1、默认值之间不触发错误，但Oracle会忽略他们使用默认值替代

  The default values of the ENQUEUE_RESOURCES and TRANSACTIONS parameters are derived from SESSIONS. Therefore, if you increase the value of SESSIONS, you should consider whether to adjust the values of ENQUEUE_RESOURCES and TRANSACTIONS as well. (Note that ENQUEUE_RESOURCES is obsolete as of Oracle Database 10g release 2 (10.2).)

  默认值的enqueue_resources和TRANSACTIONS 参数均来自会话。因此，如果你增加SESSIONS，你应该考虑是否调整enqueue_resources和TRANSACTIONS。（注意，enqueue_resources在Oracle数据库10g版本2（10.2）已经过时。）

  In a shared server environment, the value of PROCESSES can be quite small. Therefore, Oracle recommends that you adjust the value of SESSIONS to approximately 1.1 * total number of connections.

  在一个共享服务器环境中，PROCESSES值可以非常小。因此，Oracle建议约1.1×总连接数调整会话值。

  SGA_TARGET

  Property
  Description

  Parameter type
  Big integer

  Syntax
  SGA_TARGET = integer [K | M | G]

  Default value
  0 (SGA autotuning is disabled)

  Modifiable
  ALTER SYSTEM

  Range of values
  64 to operating system-dependent

  Basic
  Yes

  SGA_TARGET specifies the total size of all SGA components. If SGA_TARGET is specified, then the following memory pools are automatically sized:

  SGA_TARGET指定SGA包含的组件总共内存大小,如果SGA_TARGET指定那么 一下内存池将大小将自动设置

  • Buffer cache (DB_CACHE_SIZE)

  • Shared pool (SHARED_POOL_SIZE)

  • Large pool (LARGE_POOL_SIZE)

  • Java pool (JAVA_POOL_SIZE)

  • Streams pool (STREAMS_POOL_SIZE)

  If these automatically tuned memory pools are set to non-zero values, then those values are used as minimum levels by Automatic Shared Memory Management. You would set minimum values if an application component needs a minimum amount of memory to function properly.

  如果这些自动调谐的内存池设置为非零值，那么这些值作为最低水平的自动共享内存管理。你如果一个应用程序组件需要一个最小内存量功能正确设置最小值。

  比如large pool设置为20M那么最小值就20M

  The following pools are manually sized components and are not affected by Automatic Shared Memory Management:

  • Log buffer

  • Other buffer caches, such as KEEP, RECYCLE, and other block sizes

  • Fixed SGA and other internal allocations

  The memory allocated to these pools is deducted from the total available for SGA_TARGET when Automatic Shared Memory Management computes the values of the automatically tuned memory pools.

  SHARED_SERVERS

  Property
  Description

  Parameter type
  Integer

  Default value
  0, meaning that shared server is not on.

  If you are using shared server architecture or if the DISPATCHERS parameter is set such that the total number of dispatchers is more than 0, then the default value is 1.

  Modifiable
  ALTER SYSTEM

  Range of values
  The value of this parameter should be less than MAX_SHARED_SERVERS. If it is greater than or equal toMAX_SHARED_SERVERS, then the number of servers will not be self-tuned but will remain constant, as specified bySHARED_SERVERS.

  Basic
  Yes

  SHARED_SERVERS specifies the number of server processes that you want to create when an instance is started. If system load decreases, then this minimum number of servers is maintained. Therefore, you should take care not to set SHARED_SERVERS too high at system startup.

  STAR_TRANSFORMATION_ENABLED

  Property
  Description

  Parameter type
  String

  Syntax
  STAR_TRANSFORMATION_ENABLED =

  {TEMP_DISABLE | TRUE | FALSE}

  Default value
  FALSE

  Modifiable
  ALTER SESSION, ALTER SYSTEM

  Basic
  Yes

  STAR_TRANSFORMATION_ENABLED determines whether a cost-based query transformation will be applied to star queries.

  Values:

  • TRUE

    The optimizer will consider performing a cost-based query transformation on the star query.

  • FALSE

    The transformation will not be applied.

  • TEMP_DISABLE

    The optimizer will consider performing a cost-based query transformation on the star query but will not use temporary tables in the star transformation.

    UNDO_MANAGEMENT

    Property
    Description

    Parameter type
    String

    Syntax
    UNDO_MANAGEMENT = { MANUAL | AUTO }

    Default value
    MANUAL

    Modifiable
    No

    Basic
    Yes

    Real Application Clusters
    Multiple instances must have the same value.

    UNDO_MANAGEMENT specifies which undo space management mode the system should use. When set to AUTO, the instance starts in automatic undo management mode. In manual undo management mode, undo space is allocated externally as rollback segments.

    undo_management参数指定那个undo space 管理模式将被 系统使用 。当设置为自动启动，在自动撤销管理模式。在手动撤销管理模式下，undotablespace 将作为回滚单一样分配。

    UNDO_TABLESPACE

    Property
    Description

    Parameter type
    String

    Syntax
    UNDO_TABLESPACE = undoname

    Default value
    The first available undo tablespace in the database.

    Modifiable
    ALTER SYSTEM

    Range of values
    Legal name of an existing undo tablespace

    Basic
    Yes

    Real Application Clusters
    Each instance must have a unique value for this parameter, when it is set.

    UNDO_TABLESPACE specifies the undo tablespace to be used when an instance starts up. If this parameter is specified when the instance is in manual undo management mode, then an error will occur and startup will fail.

    undo_tablespace指定实例启动undo表空间, 如果这个参数是指定的实例是在手动撤销管理模式下，则会发生错误,启动将失败。

    If the UNDO_TABLESPACE parameter is omitted, the first available undo tablespace in the database is chosen. If no undo tablespace is available, the instance will start without an undo tablespace. In such cases, user transactions will be executed using the SYSTEM rollback segment. You should avoid running in this mode under normal circumstances.

    如果undo_tablespace参数被省略，第一个可用的undo表空间中的数据库的选择。如果没有undo表空间是可用的，该实例将没有一个撤销表空间开始。在这种情况下，用户事务将使用系统回滚段。正常情况应该避免这种情况下。

    You can replace an undo tablespace with another undo tablespace while the instance is running.