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Oracle® Database Reference
11g Release 2 (11.2)

E40402-14
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Changing Parameter Values in a Parameter File

You change the value of a parameter in a parameter file in one of the following ways:

Parameters by Functional Category

The following list shows the initialization parameters by their functional category:

Modifiable Parameters

Some initialization parameters can be modified using the ALTER SESSION or ALTER SYSTEM statements while an instance is running. Use the following syntax to modify initialization parameters:

ALTER SESSION SET parameter_name = value
ALTER SYSTEM SET parameter_name = value [DEFERRED]

Whenever a parameter is modified using the ALTER SYSTEM statement, the Oracle Database records the statement that modifies the parameter in the alert log.

The ALTER SESSION statement changes the value of the specified parameter for the duration of the session that invokes the statement. The value of the parameter does not change for other sessions in the instance. The value of the following initialization parameters can be changed with ALTER SESSION:


ASM_POWER_LIMIT
COMMIT_LOGGING
COMMIT_WAIT
COMMIT_WRITE
CREATE_STORED_OUTLINES
CURSOR_BIND_CAPTURE_DESTINATION
CURSOR_SHARING
DB_BLOCK_CHECKING
DB_CREATE_FILE_DEST
DB_CREATE_ONLINE_LOG_DEST_n
DB_FILE_MULTIBLOCK_READ_COUNT
DB_FILE_NAME_CONVERT
DB_SECUREFILE
DB_UNRECOVERABLE_SCN_TRACKING
DDL_LOCK_TIMEOUT
DEFERRED_SEGMENT_CREATION
DST_UPGRADE_INSERT_CONV
ENABLE_DDL_LOGGING
GLOBAL_NAMES
HASH_AREA_SIZE
JAVA_JIT_ENABLED
LOG_ARCHIVE_DEST_n
LOG_ARCHIVE_DEST_STATE_n
LOG_ARCHIVE_MIN_SUCCEED_DEST
MAX_DUMP_FILE_SIZE
NLS_CALENDAR
NLS_COMP
NLS_CURRENCY
NLS_DATE_FORMAT
NLS_DATE_LANGUAGE
NLS_DUAL_CURRENCY
NLS_ISO_CURRENCY
NLS_LANGUAGE
NLS_LENGTH_SEMANTICS
NLS_NCHAR_CONV_EXCP
NLS_NUMERIC_CHARACTERS
NLS_SORT
NLS_TERRITORY
NLS_TIMESTAMP_FORMAT
NLS_TIMESTAMP_TZ_FORMAT
OBJECT_CACHE_MAX_SIZE_PERCENT
OBJECT_CACHE_OPTIMAL_SIZE
OLAP_PAGE_POOL_SIZE
OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES
OPTIMIZER_DYNAMIC_SAMPLING
OPTIMIZER_FEATURES_ENABLE
OPTIMIZER_INDEX_CACHING
OPTIMIZER_INDEX_COST_ADJ
OPTIMIZER_MODE
OPTIMIZER_USE_INVISIBLE_INDEXES
OPTIMIZER_USE_PENDING_STATISTICS
OPTIMIZER_USE_SQL_PLAN_BASELINES
PARALLEL_DEGREE_LIMIT
PARALLEL_DEGREE_POLICY
PARALLEL_FORCE_LOCAL
PARALLEL_INSTANCE_GROUP
PARALLEL_IO_CAP_ENABLED
PARALLEL_MIN_PERCENT
PARALLEL_MIN_TIME_THRESHOLD
PLSCOPE_SETTINGS
PLSQL_CCFLAGS
PLSQL_CODE_TYPE
PLSQL_DEBUG
PLSQL_OPTIMIZE_LEVEL
PLSQL_V2_COMPATIBILITY
PLSQL_WARNINGS
QUERY_REWRITE_ENABLED
QUERY_REWRITE_INTEGRITY
RECYCLEBIN
REMOTE_DEPENDENCIES_MODE
RESULT_CACHE_MODE
RESULT_CACHE_REMOTE_EXPIRATION
RESUMABLE_TIMEOUT
SESSION_CACHED_CURSORS
SKIP_UNUSABLE_INDEXES
SMTP_OUT_SERVER
SORT_AREA_RETAINED_SIZE
SORT_AREA_SIZE
SQL_TRACE
SQLTUNE_CATEGORY
STAR_TRANSFORMATION_ENABLED
STATISTICS_LEVEL
TIMED_OS_STATISTICS
TIMED_STATISTICS
TRACEFILE_IDENTIFIER
WORKAREA_SIZE_POLICY
XML_DB_EVENTS

The ALTER SYSTEM statement without the DEFERRED keyword modifies the global value of the parameter for all sessions in the instance, for the duration of the instance (until the database is shut down). The value of the following initialization parameters can be changed with ALTER SYSTEM:


AQ_TM_PROCESSES
ARCHIVE_LAG_TARGET
ASM_DISKGROUPS
ASM_DISKSTRING
ASM_POWER_LIMIT
ASM_PREFERRED_READ_FAILURE_GROUPS
AWR_SNAPSHOT_TIME_OFFSET
BACKGROUND_DUMP_DEST
CIRCUITS
COMMIT_LOGGING
COMMIT_WAIT
COMMIT_WRITE
CONTROL_FILE_RECORD_KEEP_TIME
CONTROL_MANAGEMENT_PACK_ACCESS
CORE_DUMP_DEST
CPU_COUNT
CREATE_STORED_OUTLINES
CURSOR_BIND_CAPTURE_DESTINATION
CURSOR_SHARING
DB_nK_CACHE_SIZE
DB_BLOCK_CHECKING
DB_BLOCK_CHECKSUM
DB_CACHE_ADVICE
DB_CACHE_SIZE
DB_CREATE_FILE_DEST
DB_CREATE_ONLINE_LOG_DEST_n
DB_FILE_MULTIBLOCK_READ_COUNT
DB_FLASH_CACHE_SIZE
DB_FLASHBACK_RETENTION_TARGET
DB_KEEP_CACHE_SIZE
DB_LOST_WRITE_PROTECT
DB_RECOVERY_FILE_DEST
DB_RECOVERY_FILE_DEST_SIZE
DB_RECYCLE_CACHE_SIZE
DB_SECUREFILE
DB_UNRECOVERABLE_SCN_TRACKING
DDL_LOCK_TIMEOUT
DEFERRED_SEGMENT_CREATION
DG_BROKER_CONFIG_FILEn
DG_BROKER_START
DIAGNOSTIC_DEST
DISPATCHERS
DST_UPGRADE_INSERT_CONV
ENABLE_DDL_LOGGING
ENABLE_GOLDENGATE_REPLICATION
FAL_CLIENT
FAL_SERVER
FAST_START_MTTR_TARGET
FAST_START_PARALLEL_ROLLBACK
FILE_MAPPING
FIXED_DATE
GLOBAL_NAMES
GLOBAL_TXN_PROCESSES
HS_AUTOREGISTER
JAVA_JIT_ENABLED
JAVA_POOL_SIZE
JOB_QUEUE_PROCESSES
LARGE_POOL_SIZE
LDAP_DIRECTORY_ACCESS
LICENSE_MAX_SESSIONS
LICENSE_MAX_USERS
LICENSE_SESSIONS_WARNING
LISTENER_NETWORKS
LOCAL_LISTENER
LOG_ARCHIVE_CONFIG
LOG_ARCHIVE_DEST
LOG_ARCHIVE_DEST_n
LOG_ARCHIVE_DEST_STATE_n
LOG_ARCHIVE_DUPLEX_DEST
LOG_ARCHIVE_LOCAL_FIRST
LOG_ARCHIVE_MAX_PROCESSES
LOG_ARCHIVE_MIN_SUCCEED_DEST
LOG_ARCHIVE_TRACE
LOG_CHECKPOINT_INTERVAL
LOG_CHECKPOINT_TIMEOUT
LOG_CHECKPOINTS_TO_ALERT
MAX_DISPATCHERS
MAX_DUMP_FILE_SIZE
MAX_SHARED_SERVERS
MEMORY_TARGET
NLS_LENGTH_SEMANTICS
NLS_NCHAR_CONV_EXCP
OPEN_CURSORS
OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES
OPTIMIZER_DYNAMIC_SAMPLING
OPTIMIZER_FEATURES_ENABLE
OPTIMIZER_INDEX_CACHING
OPTIMIZER_INDEX_COST_ADJ
OPTIMIZER_MODE
OPTIMIZER_SECURE_VIEW_MERGING
OPTIMIZER_USE_INVISIBLE_INDEXES
OPTIMIZER_USE_PENDING_STATISTICS
OPTIMIZER_USE_SQL_PLAN_BASELINES
PARALLEL_ADAPTIVE_MULTI_USER
PARALLEL_DEGREE_LIMIT
PARALLEL_DEGREE_POLICY
PARALLEL_FORCE_LOCAL
PARALLEL_INSTANCE_GROUP
PARALLEL_IO_CAP_ENABLED
PARALLEL_MAX_SERVERS
PARALLEL_MIN_SERVERS
PARALLEL_MIN_TIME_THRESHOLD
PARALLEL_SERVERS_TARGET
PARALLEL_THREADS_PER_CPU
PGA_AGGREGATE_TARGET
PLSCOPE_SETTINGS
PLSQL_CCFLAGS
PLSQL_CODE_TYPE
PLSQL_DEBUG
PLSQL_OPTIMIZE_LEVEL
PLSQL_V2_COMPATIBILITY
PLSQL_WARNINGS
QUERY_REWRITE_ENABLED
QUERY_REWRITE_INTEGRITY
REDO_TRANSPORT_USER
REMOTE_DEPENDENCIES_MODE
REMOTE_LISTENER
RESOURCE_LIMIT
RESOURCE_MANAGER_CPU_ALLOCATION
RESOURCE_MANAGER_PLAN
RESULT_CACHE_MAX_RESULT
RESULT_CACHE_MAX_SIZE
RESULT_CACHE_MODE
RESULT_CACHE_REMOTE_EXPIRATION
RESUMABLE_TIMEOUT
SEC_CASE_SENSITIVE_LOGON
SEC_PROTOCOL_ERROR_FURTHER_ACTION
SEC_PROTOCOL_ERROR_TRACE_ACTION
SERVICE_NAMES
SGA_TARGET
SHARED_POOL_SIZE
SHARED_SERVER_SESSIONS
SHARED_SERVERS
SKIP_UNUSABLE_INDEXES
SMTP_OUT_SERVER
SPFILE
SQL_TRACE
SQLTUNE_CATEGORY
STANDBY_ARCHIVE_DEST
STANDBY_FILE_MANAGEMENT
STAR_TRANSFORMATION_ENABLED
STATISTICS_LEVEL
STREAMS_POOL_SIZE
THREAD
TIMED_OS_STATISTICS
TIMED_STATISTICS
TRACE_ENABLED
UNDO_RETENTION
UNDO_TABLESPACE
USER_DUMP_DEST
WORKAREA_SIZE_POLICY
XML_DB_EVENTS

The ALTER SYSTEM ... DEFERRED statement does not modify the global value of the parameter for existing sessions, but the value will be modified for future sessions that connect to the database. The value of the following initialization parameters can be changed with ALTER SYSTEM ... DEFERRED:


AUDIT_FILE_DEST
BACKUP_TAPE_IO_SLAVES
OBJECT_CACHE_MAX_SIZE_PERCENT
OBJECT_CACHE_OPTIMAL_SIZE
OLAP_PAGE_POOL_SIZE
RECYCLEBIN
SORT_AREA_RETAINED_SIZE
SORT_AREA_SIZE

Displaying Current Parameter Values

To see the current settings for initialization parameters, use the following SQL*Plus command:

SQL> SHOW PARAMETERS

This command displays all parameters in alphabetical order, along with their current values.

Enter the following text string to display all parameters having BLOCK in their names:

SQL> SHOW PARAMETERS BLOCK

You can use the SPOOL command to write the output to a file.

Parameters You Should Not Specify in the Parameter File

You should not specify the following two types of parameters in your parameter files:

  • Parameters that you never alter except when instructed to do so by Oracle to resolve a problem

  • Derived parameters, which normally do not need altering because their values are calculated automatically by the Oracle database server

When Parameters Are Set Incorrectly

Some parameters have a minimum setting below which an Oracle instance will not start. For other parameters, setting the value too low or too high may cause Oracle to perform badly, but it will still run. Also, Oracle may convert some values outside the acceptable range to usable levels.

If a parameter value is too low or too high, or you have reached the maximum for some resource, then Oracle returns an error. Frequently, you can wait a short while and retry the operation when the system is not as busy. If a message occurs repeatedly, then you should shut down the instance, adjust the relevant parameter, and restart the instance.