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Oracle Startup Parameters
Version 11.1.0.7
 
Documented

Query for documented initialization parameters
set pagesize 35
set linesize 150
col NAME format a30
col VALUE format a20
col DESCRIPTION format a60
set pause on
set pause 'Hit enter to continue'

SELECT x.ksppinm NAME, y.ksppstvl VALUE, ksppdesc DESCRIPTION
FROM x$ksppi x, x$ksppcv y
WHERE x.inst_id = userenv('Instance')
AND y.inst_id = userenv('Instance')
AND x.indx = y.indx
AND SUBSTR(x.ksppinm,1,1) ^= '_'
ORDER BY 1;
 
Advanced Queuing (AQ)
AQ_TM_PROCESSES

Default: 0
Required for Advanced Queuing. Valid range of vaues is 0 to 10. Zero means Oracle manages the resource.
aq_tm_processes=0
 
ANSI Compliance
BLANK_TRIMMING

Default: FALSE

Specifies the data assignment semantics of character datatypes. Allows the data assignment of a source character string or variable to a destination character column or variable even though the source length is longer than the destination length. In this case, however, the additional length over the destination length is all blanks. Range of values {TRUE | FALSE}.
blank_trimming=TRUE
 
ASM
ASM_DISKGROUPS

Default: NULL
Specifies a list of names of disk groups to be mounted by an Automatic Storage Management instance at instance startup or when an ALTER DISKGROUP ALL MOUNT statement is issued. Range of values Comma-separated list of strings, of up to 30 characters in length
asm_diskgroups=dgroupA, dgroupB
ASM_DISKSTRING

Default: NULL
An operating system-dependent value used by Automatic Storage Management to limit the set of disks considered for discovery. Value is a comma delimited string of disks.
asm_diskstring='dev/rdsk/*s2, /dev/rdsk/c1*'
ASM_POWER_LIMIT

Default: 1
Specifies the maximum power on an Automatic Storage Management instance for disk rebalancing. Range of values  {1 to 11}.
asm_power_limit=5
ASM_PREFERRED_READ_FAILURE_ GROUPS

Default: NULL
Specifies the failure groups that contain preferred read disks. Preferred disks are instance specific.
TBD
 
Archive Logging

ARCHIVE_LAG_TARGET

Default: 0
Limits the amount of data that can be lost and effectively increases the availability of the standby database by forcing a log switch after the specified amount of time elapses.

The ARCHIVE_LAG_TARGET initialization parameter causes Oracle to examine an instance's current online redo log periodically. If the following conditions are met the instance will switch the log:

* The current log was created prior to n seconds ago, and the estimated archival time for the current log is m seconds (proportional to the number of redo blocks used in the current log), where n + m exceeds the value of the ARCHIVE_LAG_TARGET initialization parameter.
* The current log contains redo records. 

In an Oracle Real Application Clusters environment, the instance also kicks other threads into switching and archiving logs if they are falling behind. This can be particularly useful when one instance in the cluster is less active than the other instances.

The parameter specifies the target of how many seconds of redo the standby could lose in the event of a primary shutdown or crash. It also provides an upper limit of how long (in the number of seconds) the current log of the primary database can span. Because the estimated archival time is also considered, this is not the exact log switch time. 

Value 0 or any integer in [60, 7200]
archive_lag_target=0
LOG_ARCHIVE_DEST Deprecated in Enterprise Edition in favour of log_archive_dest_n

LOG_ARCHIVE_DEST_n

Default: NULL
Defines up to 10 (where n = 1, 2, 3, ... 10) destinations, each of which must specify either the LOCATION or the SERVICE attribute to specify where to archive the redo data. All other attributes are optional. Whether  specifying the LOCATION or SERVICE attribute, it must be the first attribute supplied in the list of attributes.

LOG_ARCHIVE_DEST_[1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10] =
{ null_string |
{ LOCATION=path_name | SERVICE=service_name }
[ MANDATORY ]
[ REOPEN[=seconds] ]
[ DELAY[=minutes] ]
[ NOREGISTER ]
[ TEMPLATE=template ]
[ ALTERNATE=destination ]
[ DEPENDENCY=destination ]
[ MAX_FAILURE=count ]
[ SYNC | ASYNC ]
[ AFFIRM | NOAFFIRM ]
[ NET_TIMEOUT=seconds ]
[ VALID_FOR=(redo_log_type,database_role) ]
[ DB_UNIQUE_NAME ]
[ MAX_CONNECTIONS=count ]
[ COMPRESSION={ENABLE|DISABLE} ]
}
log_archive_dest_1= 'LOCATION=/app/oracle/product/flash_recovery_area/arch
valid_for=(all_logfiles,all_roles) db_unique_name=proda'

log_archive_dest_2='service=prodb valid_for=(online_logfile,primary_role) db_unique_name=prodb
NET_TIMEOUT=30 REOPEN=60 OPTIONAL MAX_CONNECTIONS=3'
LOG_ARCHIVE_DEST_STATE_n

Default: ENABLE
Specifies the state for log_archive_dest_n. Range of values {ENABLE | DEFER | ALTERNATE}.
log_archive_dest_state_1='ENABLE'

LOG_ARCHIVE_DUPLEX_DEST

Default: NULL
Similar to LOG_ARCHIVE_DEST specifies a second archive destination: the duplex archive destination. This duplex archive destination can be either a must-succeed or a best-effort archive destination, depending on how many archive destinations must succeed (as specified in the LOG_ARCHIVE_MIN_SUCCEED_DEST parameter).

The default setting of a null string ("") or (' ') indicates that a duplex archive destination does not exist.
log_archive_dest='/app/oracle/product/flash_recovery_area/arch'
log_archive_duplex_dest
='/u02/arch'

LOG_ARCHIVE_FORMAT

Default: Operating system dependent
 Use a text string and variables to specify the default filename format when archiving redo log files. The string generated from this format is appended to the string specified in the LOG_ARCHIVE_DEST parameter.

The following variables can be used in the format:
%s log sequence number
%S log sequence number, zero filled
%t thread number
%T thread number, zero filled
%a activation ID
%d database ID
%r resetlogs ID that ensures unique names are constructed for the archived log files across multiple incarnations of the database
 
Using uppercase letters for the variables (for example, %S) causes the value to be fixed length and padded to the left with zeros. An example of specifying the archive redo log filename format follows:
log_archive_format=%t+%s+%r.arc
LOG_ARCHIVE_LOCAL_FIRST

Default: TRUE
Specifies when the archiver processes (ARCn) transmit redo data to remote standby database destinations. Range of values {TRUE | FALSE}.
log_archive_local_first=TRUE

LOG_ARCHIVE_MAX_PROCESSES

Default: 4
Specifies the number of archiver background processes (ARC0 through ARCn) Oracle initially invokes. If the LOG_ARCHIVE_START initialization parameter has the value true, then this value is evaluated at instance startup though LOG_ARCHIVE_START initialization parameter was deprecated as of 10gR1. Otherwise, this parameter is evaluated when the archiver process is first invoked by SQL*Plus or SQL syntax. Range of values {1 .. 40}.
log_archive_max_processes=6
LOG_ARCHIVE_MIN_SUCCEED_DEST

Default: 1
The minimum number of destinations that must succeed for the online logfile to be available for reuse.
log_archive_min_succeed_dest=2
LOG_ARCHIVE_START Deprecated

LOG_ARCHIVE_TRACE

Default 0
Value Description
0 Disable archivelog tracing
1 Track archival of redo log file
2 Track archival status of each archivelog destination
4 Track archival operational phase
8 Track archivelog destination activity
16 Track detailed archivelog destination activity
32 Track archivelog destination parameter modifications
64 Track ARCn process state activity
128 Track FAL (fetch archived log) server related activities
256 Track RFS Logical Client
512 Track LGWR redo shipping network activity
1024 Track RFS Physical Client
2048 Track RFS/ARCn Ping Heartbeat
4096 Track Real Time Apply
8192 Track Redo Apply (Media Recovery or Physical Standby)
log_archive_trace=128
 
Auditing
AUDIT_FILE_DEST

Default: No Entry
The operating system directory into which the audit trail is written when the AUDIT_TRAIL initialization parameter is set to os. Default value ORACLE_HOME/rdbms/audit
audit_file_dest=/app/oracle/product/admin/orabase/adump
AUDIT_SYS_OPERATIONS

Default: FALSE
Enables or disables the auditing of operations issued by user SYS, and users connecting with SYSDBA or SYSOPER privileges. Syntax AUDIT_SYS_OERATIONS = {TRUE | FALSE}
audit_sys_operations=TRUE
AUDIT_TRAIL

Default: NONE
Enables or disables database auditing. Syntax AUDIT_TRAIL = {DB | OS | NONE | TRUE | FALSE | DB_EXTENDED}
audit_trail='DB'
 
Backup and Restore
BACKUP_TAPE_IO_SLAVES

Default: FALSE
Specifies if I/O server processes (also called slaves) are used by Recovery Manager to back up, copy, or restore data to tape. Range of values TRUE | FALSE
backup_tape_io_slaves=FALSE
CONTROL_FILE_RECORD_KEEP_TIME

Default: 7
specifies the minimum number of days before a reusable record in the control file can be reused. In the event a new record needs to be added to a reusable section and the oldest record has not aged enough, the record section expands. If this parameter is set to 0, then reusable sections never expand, and records are reused as needed. Range of values 0 to 365 (days)
control_file_record_keep_time=15
FAST_START_IO_TARGET Deprecated in favor of FAST_START_MTTR_TARGET
FAST_START_MTTR_TARGET Specify the number of seconds the database takes to perform crash recovery of a single instance. Is overridden by FAST_START_IO_TARGET and LOG_CHECKPOINT_INTERVAL. Range of 0 to 3600 seconds.
fast_start_mttr_target=0
TAPE_ASYNCH_IO

Default: TRUE
Controls whether I/O to sequential devices (for example, backup or restore of Oracle data to or from tape) is asynchronous. Range of values {TRUE | FALSE}.
tape_asynch_io=FALSE
 
BFILEs
SESSION_MAX_OPEN_FILES

Default: 10
Specifies the maximum number of BFILEs that can be opened in any session. Once this number is reached, subsequent attempts to open more files in the session by using DBMS_LOB.FILEOPEN() or OCILobFileOpen() will fail.
session_max_open_files=6
 
Buffer Cache and I/O
DB_nK_CACHE_SIZE

Defaults: 0
Specifies the size of the cache for the nK buffers. You can set this parameter only when DB_BLOCK_SIZE has a value other than nK. Range of values Minimum: 0 (values greater than zero are rounded up to the nearest granule size)
db_4K_cache_size=8M
DB_BLOCK_BUFFERS

Default: 0
Specifies the number of database buffers in the buffer cache. It is one of several parameters that contribute to the total memory requirements of the SGA of an instance. Range of values 50 to an operating system-specific maximum. DB_BLOCK_BUFFERS cannot be combined with the dynamic DB_CACHE_SIZE parameter.
db_block_buffers=10000
DB_BLOCK_SIZE Specifies (in bytes) the size of Oracle database blocks. 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.

Range of values 2048 to 32768, but your operating system may have a narrower range
db_block_size=8192
DB_CACHE_ADVICE

Default: ON
Enables or disables statistics gathering used for predicting behavior with different cache sizes through the V$DB_CACHE_ADVICE performance view.

Syntax DB_CACHE_ADVICE = {ON | READY | OFF}
db_cache_advice=READY
DB_CACHE_SIZE

Default 0 ... if SGA_TARGET is set..
Specifies the size of the DEFAULT buffer pool for buffers with the primary block size (the block size defined by the DB_BLOCK_SIZE initialization parameter).

Syntax DB_CACHE_SIZE = integer [K | M | G]. A value of zero is illegal.
db_cache_size=48M

DB_FILE_MULTIBLOCK_READ_COUNT

Default: 8
One of the parameters you can use to minimize I/O during table scans. It specifies the maximum number of blocks read in one I/O operation during a sequential scan (applies to full table scans and index fast full scans, so non-random I/O.). The total number of I/Os needed to perform a full table scan depends on such factors as the size of the table, the multiblock read count, and whether parallel execution is being utilized for the operation.

Online transaction processing (OLTP) and batch environments typically have values in the range of 4 to 16 for this parameter. DSS and data warehouse environments tend to benefit most from maximizing the value of this parameter. The optimizer is more likely to choose a full table scan over an index if the value of this parameter is high.

The maximum value is always less than the operating system's maximum I/O size expressed as Oracle blocks ((max I/O size)/DB_BLOCK_SIZE). If you set this parameter to a value greater than the maximum, Oracle uses the maximum.

Depending on your exact version and the use of system statistics with version 9+ larger values for the db_file_multiblock_read_count parameter influence the cost based optimizer to favor full table scans
over using indexes. Range of values Operating system-dependent.
db_file_multiblock_read_count=128
DB_KEEP_CACHE_SIZE

Default: 0
Specifies the size of the KEEP buffer pool. The size of the buffers in the KEEP buffer pool is the primary block size (the block size defined by the DB_BLOCK_SIZE initialization parameter). Minimum: 0 (values greater than zero are rounded up to the nearest granule size) Maximum: operating system-dependent.
db_keep_cache_size=128K
DB_RECYCLE_CACHE_SIZE

Default: 0
Specifies the size of the RECYCLE buffer pool. The size of the buffers in the RECYCLE pool is the primary block size (the block size defined by the DB_BLOCK_SIZE initialization parameter).  Minimum: 0 (values greater than zero are rounded up to the nearest granule size) Maximum: operating system-dependent.
db_recycle_cache_size=64K
DB_WRITER_PROCESSES Specifies the initial number of database writer processes for an instance. Range of values 1 to 20
TBD

DBWR_IO_SLAVES
Relevant only on systems with only one database writer process (DBW0). It specifies the number of I/O server processes used by the DBW0 process. The DBW0 process and its server processes always write to disk. By default, the value is 0 and I/O server processes are not used.

If you set DBWR_IO_SLAVES to a nonzero value, the number of I/O server processes used by the ARCH and LGWR processes is set to 4. However, the number of I/O server processes used by Recovery Manager is set to 4 only if asynchronous I/O is disabled (either your platform does not support asynchronous I/O or disk_asynch_io is set to false).

Typically, I/O server processes are used to simulate asynchronous I/O on platforms that do not support asynchronous I/O or that implement it inefficiently. However, you can use I/O server processes even when asynchronous I/O is being used. In that case the I/O server processes will use asynchronous I/O.

I/O server processes are also useful in database environments with very large I/O throughput, even if asynchronous I/O is enabled.
Range of values 0 to operating system-dependent
TBD

DISK_ASYNCH_IO

Default: TRUE
Controls whether I/O to datafiles, control files, and logfiles is asynchronous (that is, whether parallel server processes can overlap I/O requests with CPU processing during table scans. Oracle recommends that you leave this parameter set to its default value. However, if the asynchronous I/O implementation is not stable, you can set this parameter to false to disable asynchronous I/O. If your platform does not support asynchronous I/O to disk, this parameter has no effect.

If you set DISK_ASYNCH_IO to false, then you should also set DBWR_IO_SLAVES to a value other than its default of zero in order to simulate asynchronous I/O.
Range of values TRUE | FALSE
TBD
FILESYSTEMIO_OPTIONS  
TBD
READ_ONLY_OPEN_DELAYED  
TBD
USE_INDIRECT_DATA_BUFFERS  
TBD
 
Cursors and Library Cache

CURSOR_SHARING

Default: Exact
FORCE: Forces statements that may differ in some literals, but are otherwise identical, to share a cursor, unless the literals affect the meaning of the statement.

SIMILAR: Causes statements that may differ in some literals, but are otherwise identical, to share a cursor, unless the literals affect either the meaning of the statement or the degree to which the plan is optimized.

EXACT: Only allows statements with identical text to share the same cursor.
Syntax CURSOR_SHARING = {SIMILAR | EXACT | FORCE}
TBD

CURSOR_SPACE_FOR_TIME

Default: FALSE

Deprecated as of 10.2.0.5 and 11.1.0.7
Shared SQL areas are kept pinned in the shared pool. As a result, shared SQL areas are not aged out of the pool as long as an open cursor references them. Because each active cursor's SQL area is present in memory, execution is faster. However, the shared SQL areas never leave memory while they are in use. Therefore, you should set this parameter to TRUE only when the shared pool is large enough to hold all open cursors simultaneously.

In addition, a setting of TRUE retains the private SQL area allocated for each cursor between executions instead of discarding it after cursor execution, saving cursor allocation and initialization time. 

FALSE: Shared SQL areas can be deallocated from the library cache to make room for new SQL statements.
Syntax CURSOR_SPACE_FOR_TIME = {TRUE | FALSE}
TBD
OPEN_CURSORS x
TBD
SESSION_CACHED_CURSORS x
TBD
 
Data Guard

DG_BROKER_CONFIG_FILEn
Specifies the names for the Data Guard broker configuration files. Every database that is part of a Data Guard broker configuration has two broker configuration files, which contain entries that describe the state and properties of the configuration (such as the sites and databases that are part of the configuration, the roles and properties of each of the databases, and the state of each of the elements of the configuration). Two files are provided so as to always maintain the last known good state of the configuration.

If DG_BROKER_CONFIG_FILEn is not explicitly defined, then it is set to an operating system-specific default value at instance startup. The parameter can only be altered when the DMON (Data Guard broker) process is not running.
Range of values One filename
DG_BROKER_START

Default: FALSE
Enables Oracle to determine whether or not the DMON (Data Guard broker) process should be started. Range of values {[TRUE | FALSE}.
TBD
DRS_START

Default: FALSE
Start DG Broker monitor (DMON process). Range of values {[TRUE | FALSE}.
TBD
DB_FILE_NAME_CONVERT

Defalt: NULL
Useful for creating a duplicate database for recovery purposes. You can also use DB_FILE_NAME_CONVERT to rename the datafiles in the clone controlfile when setting up a clone database during tablespace point-in-time recovery.
Syntax DB_FILE_NAME_CONVERT = 'string1' , 'string2' , 'string3' , 'string4' , ...
LOG_ARCHIVE_CONFIG

Default: 'SEND,RECEIVE,NODG_CONFIG'
Enables or disables the sending of redo logs to remote destinations and the receipt of remote redo logs, and specifies the unique database names (DB_UNIQUE_NAME) for each database in the Data Guard configuration. Range of values {DG_CONFIG | NODG_CONFIG | NORECEIVE | NOSEND | RECEIVE | SEND}.
log_archive_config='DG_CONFIG=(proda,prodb)'
 
Database / Instance / Identification
DB_DOMAIN

Default: NULL
In a distributed database system, DB_DOMAIN specifies the logical location of the database within the network structure.

Range of values is any legal string of name components, separated by periods and up to 128 characters long (including the periods). This value cannot be NULL.
db_domain='PSOUG.ORG'
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.
db_name=database_name
 
Data Guard
FAL_CLIENT Specifies the FAL (fetch archive log) client name that is used by the FAL service
FAL_CLIENT = string
FAL_SERVER Specifies the FAL (fetch archive log) server for a standby database
FAL_SERVER = string
 
Diagnostics / Statistics
BACKGROUND_CORE_DUMP

Default: partial
Specifies whether Oracle includes the SGA in the core file for Oracle background processes. Syntax BACKGROUND_CORE_DUMP = {PARTIAL | FULL}
background_core_dump=partial
BACKGROUND_DUMP_DEST Deprecated and ignored in 11g
CORE_DUMP_DEST

Default: {ORACLE_HOME}/dbs
Primarily a UNIX parameter not supported on all platforms. Specifies the directory for core file dumps
core_dump_dest='/app/oracle/product/diag/rdbms/orabase/orabase/cdump'
DB_BLOCK_CHECKING

Default FALSE
Controls whether Oracle performs block checking for data blocks. When this parameter is set to TRUE, Oracle performs block checking for all data blocks. When it is set to false, Oracle does not perform block checking for blocks in the user tablespaces. However, block checking for the SYSTEM tablespace is always turned on.
Range of values TRUE | FALSE
DB_BLOCK_CHECKSUM

Default: TRUE
Determines whether DBWn and the direct loader will calculate a checksum (a number calculated from all the bytes stored in the block) and store it in the cache header of every data block when writing it to disk. Checksums are verified when a block is read-only if this parameter is TRUE and the last write of the block stored a checksum. In addition, Oracle gives every log block a checksum before writing it to the current log.
Range of values TRUE | FALSE
SHADOW_CORE_DUMP Specifies whether Oracle includes the SGA in the core file for foreground (client) processes. Valid values are: PARTIAL, FULL, NONE
TBD
 
Distributed Replication
COMMIT_POINT_STRENGTH

Default: 1
relevant only in distributed database systems. Specifies a value that determines the commit point site in a distributed transaction. The node in the transaction with the highest value for COMMIT_POINT_STRENGTH will be the commit point site. Range of values 0 to 255.
TBD
DISTRIBUTED_LOCK_TIMEOUT

Default: 60
Specifies the amount of time (in seconds) for distributed transactions to wait for locked resources. Range of values 1 to unlimited.
TBD
GLOBAL_NAMES  
TBD
HS_AUTOREGISTER  
TBD
OPEN_LINKS  
TBD
OPEN_LINKS_PER_INSTANCE  
TBD
REPLICATION_DEPENDENCY
_TRACKING
 
TBD
 
Exadata Storage Server (new in 11.1.0.7)
CELL_OFFLOAD_COMPACTION

Default: ADAPTIVE
 
TBD
CELL_OFFLOAD_PARAMETERS  
TBD
CELL_OFFLOAD_PLAN_DISPLAY

Default: AUTO
 
TBD
CELL_OFFLOAD_PROCESSING

Default: TRUE
 
TBD
CELL_PARTITION_LARGE_EXTENTS

Default: DEFAULT
 
TBD
 
File Locations, Names, and Sizes
CONTROL_FILES Control file names list [file_path,file_path..]
*.control_files='c:\oracle\product\oradata\orabase\control01.ctl', 'c:\oracle\product\oradata\orabase\control02.ctl', 'c:\oracle\product\oradata\orabase\control03.ctl'
DB_CREATE_FILE_DEST

Default: NULL
Specifies the default location for Oracle-Managed datafiles (OMF).
db_create_file_dest = directory | disk group
db_create_file_dest='/u01/oradata/orabase'
DB_CREATE_ONLINE_LOG_DEST_n

Default: NULL
Specifies the default location for Oracle-managed control files and online redo logs.
Syntax DB_CREATE_ONLINE_LOG_DEST_[1 | 2 | 3 | 4 | 5] = directory | disk group
DB_FILES

Default: 200
Minimum: the largest among the absolute file numbers of the datafiles in the database
Maximum: operating system-dependent
Specifies the maximum number of database files that can be opened for this database.
DB_RECOVERY_FILE_DEST Specifies the default location for the flash recovery area.
Syntax DB_RECOVERY_FILE_DEST = {DIRECTORY | DISK GROUP}
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.
Syntax DB_RECOVERY_FILE_DEST_SIZE = integer [K | M | G]
FILE_MAPPING x
TBD
IFILE Include the file into the init.ora as it is read.
ifile=?/dbs/proda_dg.ora
SPFILE  
spfile=/app/oracle/product/11.1.0/db_1/dbs/spfileorabase.ora
 
Flashback
DB_FLASHBACK_RETENTION_TARGET

Default: 1440
Specifies the upper limit (in minutes) on how far back in time the database may be flashed back.
Range of values 0 to 232 - 1 (max value represented by 32 bits)
RECYCLEBIN

Default: ON
Specifies if the recyclebin holds dropped tables and associated indexes. Range of values {ON | OFF}
recyclebin=ON
 
Instance Managment
INSTANCE_GROUPS  
TBD
INSTANCE_NAME  
TBD
INSTANCE_NUMBER  
TBD
INSTANCE_TYPE  
instance_type=RDBMS
 
I/O
FILEIO_NETWORK_ADAPTERS  
TBD
FILESYSTEMIO_OPTIONS  
TBD
 
Java
JAVA_JIT_ENABLED  
TBD
java_max_sessionspace_size  
TBD
JAVA_POOL_SIZE  
TBD
java_soft_sessionspace_limit  
TBD
 
Memory Allocation Sizing and Usage
BITMAP_MERGE_AREA_SIZE

Default: 1048576 for W2K & Linux

For systems containing bitmap indexes: Specifies the amount of memory Oracle uses to merge bitmaps retrieved from a range scan of the index. The default value is 1 MB. A larger value usually improves performance, because the bitmap segments must be sorted before being merged into a single bitmap. Range of values Operating system-dependent
bitmap_merge_area_size=1048576
BUFFER_POOL_KEEP

Default: NULL

Number of database blocks/latches in keep buffer pool [CHAR: (buffers:n, latches:m)]
buffer_pool_keep=TRUE
BUFFER_POOL_RECYCLE

Default: NULL

Number of database blocks/latches in recycle buffer pool [CHAR: (buffers:n, latches:m)]
buffer_pool_recycle=TRUE
CREATE_BITMAP_AREA_SIZE

Default: 8388608
Relevant only for systems containing bitmap indexes. It specifies the amount of memory (in bytes) allocated for bitmap creation. The default value is 8 MB. A larger value may speed up index creation.
Range of values Operating system-dependent.
GLOBAL_CONTEXT_POOL_SIZE  
TBD
HASH_AREA_SIZE  
TBD
HI_SHARED_MEMORY_ADDRESS  
TBD
LARGE_POOL_SIZE  
TBD
MEMORY_MAX_TARGET  
TBD
MEMORY_TARGET  
TBD
 
NLS Parameters
NLS_CALENDAR  
TBD
NLS_COMP  
TBD
NLS_CURRENCY  
TBD
NLS_DATE_FORMAT  
TBD
NLS_DATE_LANGUAGE  
TBD
NLS_DUAL_CURRENCY  
TBD
NLS_ISO_CURRENCY  
TBD
NLS_LANGUAGE  
TBD
NLS_LENGTH_SEMANTICS  
TBD
NLS_NCHAR_CONV_EXCP  
TBD
NLS_NUMERIC_CHARACTERS  
TBD
NLS_SORT  
TBD
NLS_TERRITORY  
TBD
NLS_TIME_FORMAT  
TBD
NLS_TIME_TZ_FORMAT  
TBD
NLS_TIMESTAMP_FORMAT  
TBD
NLS_TIMESTAMP_TZ_FORMAT  
TBD
 
Optimizer
CREATE_STORED_OUTLINES

Default: NULL
Enables automatic outline creation for subsequent queries in the same session. These outlines receive a unique system-generated name and are stored in the DEFAULT category. If a particular query already has an outline defined for it in the DEFAULT category, then that outline will remain and a new outline will not be created.
Syntax CREATE_STORED_OUTLINES = {TRUE | FALSE | CATEGORY_NAME}

OPTIMIZER_INDEX_CACHING
A point that is often overlooked with optimizer_index_caching is that it supposed to apply only for index costs during nested loops (although it does seem to be applied for inlist iterators).

Consequently it is not really a measure of what fraction of an index is cached, it is a measure of how many rows I
select from a driving table that require me to collect the same data from the inner table repeatedly.

For example:
If I select 5 rows from table A and then join to table B, it is possible that I will do a physical read for the index blocks for tableB after reading the first row from table A - but then use the same index blocks for the join to the next 4 rows from table A.

In this case, an optimizer_index_caching value of 80% would be the representative value.

by: Jonathan Lewis / 4 Nov 2004

A relevant metalink note (62286.1) would suggest that Oracle intend the
value to be considered for in-list as well as NL.

by: Niall Litchfield
TBD
 
Real Application Clusters

ACTIVE_INSTANCE_COUNT

Default: NULL
Designate one instance in a two-instance cluster as the primary instance and the other instance as the secondary instance. This parameter has no functionality in a cluster with more than two instances.

Range of values 1 or >= the number of instances in the cluster. (Values other than 1 have no effect on the active or standby status of any instances.)
TBD
CLUSTER_DATABASE

Default: FALSE
Specifies whether or not Real Application Clusters is enabled. Range of values TRUE | FALSE
cluster_database=TRUE
CLUSTER_DATABASE_INSTANCES

Default: 1
Specifies the number of instances that are configured as part of a RAC database. Range of values Any nonzero value
cluster_database_instances=4
CLUSTER_INTERCONNECTS

Default: NULL
Range of values One or more IP addresses, separated by colons. Provides information about additional cluster interconnects available for use in a RAC environments.
TBD
 
Result Cache
CLIENT_RESULT_CACHE_LAG ?
client_result_cache_lag=3000
CLIENT_RESULT_CACHE_SIZE ?
client_result_cache_size=0
 
Security
O7_DICTIONARY_ACCESSIBILITY

Default: FALSE
Version 7 Dictionary Accessibility support. Range of values TRUE or FALSE
07_dictionary_accessibility=FALSE
DB_SECUREFILE
Default: PERMITTED
x
Requires the tablespace is created with SEGMENT SPACE MANAGEMENT = AUTO
TBD
LDAP_DIRECTORY_ACCESS  
TBD
LDAP_DIRECTORY_SYSAUTH  
TBD
MAX_ENABLED_ROLES  
TBD
 
Statistics and Tracing
COMMIT_LOGGING x
TBD

DIAGNOSTIC_DEST
Replacement for BDUMP and UDUMP related parameters. Points to ADR_BASE
col name_col_plus_show_param format a30
col type format a10
col value_col_plus_show_param format a30

show parameter diag
ENABLE_DDL_LOGGING

Default: FALSE
X
enable_ddl_logging=TRUE
EVENT Debug event control - default null string [CHAR]
Do not alter the value of this parameter except under the supervision of Oracle Support Services staff
MAX_DUMP_FILE_SIZE Specifies the maximum size of trace files (excluding the alert file).

Valid values are: 0 to unlimited
TBD
STATISTICS LEVEL Specifies the level of collection for database and operating system statistics. The Oracle Database collects these statistics for a variety of purposes, including making self-management decisions. Valid values are: ALL, TYPICAL, BASIC
TBD
TIMED_OS_STATISTICS When TRUE statistics are collected and stored in trace files or displayed in the V$SESSTATS and V$SYSSTATS dynamic performance views
TBD
TRACE_ENABLED Controls tracing of the execution history, or code path, of Oracle. Oracle Support Services uses this information for debugging.
TBD
TRACEFILE_IDENTIFIER Specifies a custom identifier that becomes part of the Oracle Trace file name. A custom identifier is used to identify a trace file simply from its name and without having to open it or view its contents.
TBD
USER_DUMP_DEST Deprecated and Ignored in 11g
 
Transactions
COMMIT_WAIT ?
TBD
COMMIT_WRITE ?
TBD
DDL_WAIT_FOR_LOCKS

Default: FALSE
Specifies whether DDL statements (such as ALTER TABLE ... ADD COLUMN) wait and complete instead of timing out if the statement is not able to acquire all required locks.
Range of values TRUE | FALSE
DML_LOCKS

Default value Derived: 4 * TRANSACTIONS. Specifies the maximum number of DML locks—one for each table modified in a transaction. The value should equal the grand total of locks on tables currently referenced by all users. For example, if three users are modifying data in one table, then three entries would be required. If three users are modifying data in two tables, then six entries would be required.
Range of values 20 to unlimited; a setting of 0 disables enqueues
FAST_START_PARALLEL_ROLLBACK Determines the maximum number of processes that can exist for performing parallel rollback. This parameter is useful on systems in which some or all of the transactions are long running
Range of values {HI | LO | FALSE}
GLOBAL_TXN_PROCESSES x
TBD
 
 
CIRCUITS Specifies the total number of virtual circuits that are available for inbound and outbound network sessions. It is one of several parameters that contribute to the total SGA requirements of an instance. No default value.
TBD
COMPATIBLE Allows you to use a new release of Oracle, while at the same time guaranteeing backward compatibility with an earlier release. This is not TRUE with 10g so be sure to read the documentation carefully.
Range of values for 10g: 9.2.0 to default release value
CPU_COUNT Specifies the number of CPUs available to Oracle. Range of values 0 to unlimited.
cpu_count=1
DB_UNIQUE_NAME Specifies a globally unique name for the database. Databases with the same DB_NAME within the same DB_DOMAIN. Every database's DB_UNIQUE_NAME must be unique within the enterprise.
Syntax DB_UNIQUE_NAME = database_unique_name
DISPATCHERS  
TBD
ENQUEUE_RESOURCES Resources for enqueues [NUMBER]
Not modifiable. Derived from the SESSIONS parameter
FIXED_DATE  
TBD
GC_FILES_TO_LOCKS  
TBD
gcs_server_processes  
TBD
job_queue_processes  
TBD
LICENSE_MAX_SESIONS  
TBD
LICENSE_MAX_USERS  
TBD
LICENSE_SESSIONS_WARNING  
TBD
CONTROL_MANAGEMENT_PACK _ACCESS  
TBD
DB_CACHE_ADVISE  
TBD
DB_LOST_WRITE_PROTECT  
TBD
DB_ULTRA_SAFE  
TBD
DDL_LOCK_TIMEOUT  
TBD
LOCAL_LISTENER  
TBD
LOCK_NAME_SPACE  
TBD
LOCK_SGA  
TBD
LOG_BUFFER  
TBD
LOG_CHECKPOINT_INTERVAL  
TBD
LOG_CHECKPOINT_TIMEOUT  
TBD
LOG_CHECKPOINTS_TO_ALERT  
TBD
LOG_FILE_NAME_CONVERT  
TBD
MAX_COMMIT_PROPAGATION_DELAY  
TBD
MAX_DISPLATCHERS  
TBD
MAX_SHARED_SERVERS  
TBD
 
Undocumented

Query for undocumented initialization parameters
set pagesize 35
set linesize 150
col NAME format a40
col VALUE format a20
col DESCRIPTION format a60
set pause on
set pause 'Hit enter to continue'

SELECT x.ksppinm NAME,
y.ksppstvl VALUE,
ksppdesc DESCRIPTION
FROM x$ksppi x, x$ksppcv y
WHERE x.inst_id = userenv('Instance')
AND y.inst_id = userenv('Instance')
AND x.indx = y.indx
AND SUBSTR(x.ksppinm,1,1) = '_'
ORDER BY 1;

_CORRUPTED_ROLLBACK_SEGMENTS


Default: TRUE
Marks an undo segment as corrupt so it can be dropped
SQL> select segment_name, tablespace_name, status from dba_rollback_segs;

SEGMENT_NAME                   TABLESPACE_NAME                STATUS
------------------------------ ------------------------------ --------------
SYSTEM                         SYSTEM                         ONLINE
_SYSSMU1_1222867085$           UNDOTBS1                       NEEDS RECOVERY
_SYSSMU20_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU19_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU18_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU17_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU16_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU15_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU14_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU13_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU12_1235038139$          UNDOTBS2                       ONLINE
_SYSSMU11_1235038139$          UNDOTBS2                       ONLINE

SQL> create pfile from spfile;

SQL> shutdown abort

-- edit pfile and add
_corrupted_rollback_segments=('_SYSSMU1_1222867085$')

SQL> create spfile from pfile

SQL> startup

SQL> drop rollback segment "_SYSSMU1_1222867085$";
_NEWSORT_ENABLED

Default: TRUE
Activates new sorting algorithm in 10gR2
Range of values TRUE | FALSE

alter session set "_newsort_enabled"=FALSE;
_SYSTEM_TRIG_ENABLED

Default: TRUE
If set to FALSE system triggers will not fire
Range of values TRUE | FALSE

alter session set "_system_trig_enabled"=FALSE;
_TRACE_FILES_PUBLIC

Default: FALSE
Sets the file protection mask to 644
Range of values TRUE | FALSE

alter session set "_trace_files_public"=TRUE;

_UNNEST_SUBQUERY

Default: TRUE
_unnest_subquery = FALSE
Range of values TRUE | FALSE

EXPLAIN PLAN FOR
SELECT srvr_id
FROM servers
WHERE srvr_id IN (
  SELECT srvr_id
  FROM serv_inst);

SELECT * FROM TABLE(dbms_xplan.display);

alter session set "_unnest_subquery"=FALSE;

EXPLAIN PLAN FOR
SELECT srvr_id
FROM servers
WHERE srvr_id IN (
  SELECT srvr_id
  FROM serv_inst);

SELECT * FROM TABLE(dbms_xplan.display);
 
Other Related Topics
Init.ora & SPFILE
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