Oracle Undocumented Underscore Startup Parameters
Version 21c
Page 2 of 5

General Information
Library Note Morgan's Library Page Header
ACE Director Alum Daniel Morgan, founder of Morgan's Library, is scheduling complimentary technical Workshops on Database Security for the first 30 Oracle Database customers located anywhere in North America, EMEA, LATAM, or APAC that send an email to asra_us@oracle.com. Request a Workshop for your organization today.
Purpose The "undocumented" underscore parameters are parameters officially undocumented and unsupported by Oracle but that may be utilized, after receiving permission from Oracle Support to address specific issues such as bugs.

The current page is numbered 2 of 5 and has been posted to the Library. Additional pages and sections will be published as they are completed.

For a list of deprecated and removed parameters view $ORACLE_HOME/rdbms/admin/parameters.properties
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, x.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(LOWER(x.ksppinm),1,1) = '_'
ORDER BY 1;
Page Index
Sections
Active Session History Data Guard KCFIS
Adaptive Queries Data Pump Memory
ADDM DB Block Network & Connectivity
Advanced Queuing DB Cache

Destinations		 NLS Parameters
Archive Logging Diagnostics Optimizer
Audit Distributed Replication PL/SQL
Automatic Storage Management Exadata RAC
Automatic Workload Repository File Locations Result Cache
Backup & Restore Flashback Security
Block Change Tracking Group By Tracing
Bloom Filters Hang Manager Transactions
Buffers In-Memory Undo
Compression Instance Identification Miscellaneous
Container_Database I/O Undocumented
 
Buffers
_BA_CF_TRACE_BUFFER_SIZE
Default: 131072		 Size of per-process I/O KBC trace buffer
TBD
_BACKUP_DYNAMIC_BUFFERS
Default: TRUE		 Dynamically compute backup/restore buffer sizes
TBD
_BUDDY_INSTANCE_NUM_READ_BUFFERS
Default: 4		 Number of Read Buffers to scan every time in Buddy Instance feature
TBD
_BUFFER_BSY_WAIT_TIMEOUT
Default: 100		 Buffer busy wait time in centiseconds
TBD
_BUFFERED_MESSAGE_SPILL_AGE
Default: 300		 Buffered message spill age
TBD
_BUFFERED_PUBLISHER_FLOW_CONTROL _THRESHOLD
Default: 0		 Flow control threshold for buffered publishers except capture
TBD
_CAPTURE_BUFFER_SIZE
Default: 65536		 To set the size of the PGA I/O recording buffers
TBD
_CHANGE_VECTOR_BUFFERS
Default: 1		 Number of change vector buffers for media recovery
TBD
_CLEANOUT_SHRCUR_BUFFERS
Default: TRUE		 If TRUE, cleanout shrcur buffers
TBD
_CLEAR_BUFFER_BEFORE_REUSE
Default: FALSE		 Always zero-out buffer before reuse for security
TBD
_CLEAR_PRESERVED_BUFFERS
Default: TRUE		 Clear preserved buffers before DB reopen after switchover
TBD
_COORD_MESSAGE_BUFFER
Default: 0		 Parallel recovery coordinator side extra message buffer size
TBD
_CURSOR_DB_BUFFERS_PINNED
Default: 817		 Additional number of buffers a cursor can pin at once
TBD
_DATA_WAREHOUSING_SCAN_BUFFERS
Default: TRUE		 If TRUE, enable data warehousing scan buffers
TBD
_DATA_WAREHOUSING_SCAN_FLASH_BUFFERS
Default: FALSE		 If TRUE, enable data warehousing scan flash buffers
TBD
_DB_BLOCK_BUFFERS
Default: 262372		 Number of database blocks cached in memory: hidden parameter
TBD
_DB_BLOCK_TABLE_SCAN_BUFFER_SIZE
Default: 4194304		 Size of shared table scan read buffer
TBD
_DB_FILE_FORMAT_IO_BUFFERS
Default: 4		 Block formatting I/O buf count
TBD
_DB_WRITER_COALESCE_ENCRYPTED_BUFFERS
Default: TRUE		 Coalescing for encrypted buffers
TBD
_ENABLE_BUFFER_HEADER_HISTORY
Default: TRUE		 If TRUE, records operation history in buffer headers
TBD
_FLUSH_LOG_BUFFER_FORCE
Default: FALSE		 Flush log buffer force
TBD
_FLUSH_LOG_BUFFER_TIMEOUT
Default: 0		 Flush log buffer wait time in seconds
TBD
_GC_KEEP_RECOVERY_BUFFERS
Default: TRUE		 If TRUE, make recovery buffers current
TBD
_GC_KEEP_UNDO_RECOVERY_BUFFERS
Default: TRUE		 If TRUE, make recovery undo buffers current
TBD
_GC_MSGQ_BUFFERS
Default: 0		 Set number of MSGQ buffers
TBD
_GC_SANITY_CHECK_CR_BUFFERS
Default: FALSE		 If TRUE, sanity check CR buffers
TBD
_KDLI_BUFFER_INJECT
Default: TRUE		 Use buffer injection for CACHE [NO]LOGGING lobs
TBD
_KDT_BUFFERING
Default: TRUE		 Control kdt buffering for conventional inserts
TBD
_KRA_TRACE_BUFFER_SIZE
Default: 131072		 Size of I/O trace buffer
TBD
_KRB_TRACE_BUFFER_SIZE
Default: 131072		 Size of per-process I/O trace buffer
TBD
_KRBABR_TRACE_BUFFER_SIZE
Default: 131072		 Size of I/O trace buffer
TBD
_KRC_TRACE_BUFFER_SIZE
Default: 131072		 Size of I/O trace buffer
TBD
_KRPM_TRACE_BUFFER_SIZE
Default: 262144		 Size of per-process mira trace buffer
TBD
_LM_COMM_MSGQ_COPY_BUFFERS
Default: FALSE		 MSGQ_DRMQ copy msgs to new buffer
TBD
_LM_COMM_MSGQ_FIXED_BUFFERS
Default: FALSE		 MSGQ with fixed number of receive buffers
TBD
_LM_POSTEVENT_BUFFER_SIZE
Default: 256		 Post event buffer size
TBD
_LOG_ARCHIVE_BUFFERS
Default: 4		 Number of buffers to allocate for archiving
TBD
_LOG_BUFFER_COALESCE
Default: FALSE		 Coalescing log buffers for log writes
TBD
_LOG_BUFFERS_CORRUPT
Default: FALSE		 Corrupt redo buffers before write
TBD
_LOG_BUFFERS_DEBUG
Default: FALSE		 Debug redo buffers (slows things down)
TBD
_LOG_READ_BUFFER_SIZE
Default: 8		 Buffer size for reading log files
TBD
_LOG_READ_BUFFERS
Default: 8		 Number of log read buffers for media recovery
TBD
_MIRA_FREE_UNUSED_BUFFERS
Default: TRUE		 Free unused buffers when idle
TBD
_MIRA_NUM_LOCAL_BUFFERS
Default: 25		 Number of local buffers for multi instance media recovery
TBD
_MIRA_NUM_RECEIVE_BUFFERS
Default: 25		 Number of receive buffers for multi instance media recovery
TBD
_MIRA_RCV_CATCHUP_BUFFERS
Default: 5		 Number of buffers to allocate before catch up
TBD
_MIRA_RCV_MAX_BUFFERS
Default: 500		 Maximum number of outstanding buffers
TBD
_MIRROR_REDO_BUFFERS
Default: FALSE		 Save buffers for debugging redo corruptions
TBD
_NOLOGGING_STANDB_COLD_BUFFER_TIMEOUT
Default: 500		 Centisecs recovery will wait for buffer not sent by direct load client in Nologging Stdby Data Availability mode
TBD
_NOLOGGING_STANDBY_HOT_BUFFER_TIMEOUT
Default: 500		 Centisecs recovery will wait for buffer sent by direct load client in Nologging Stdby Data Availability mode
TBD
_NONCE_HISTORY_BUFFER_SIZE
Default: 0		 Size of Nonce History Buffer
TBD
_OFS_WRITE_BUFFER_SIZE
Default: 1048576		 OFS write buffer size in bytes
TBD
_OLAP_AGGREGATE_BUFFER_SIZE
Default: 1048576		 OLAP Aggregate max buffer size
TBD
_OLAP_AGGREGATE_MIN_BUFFER_SIZE
Default: 1024		 OLAP Aggregate min buffer size
TBD
_OLAP_SORT_BUFFER_PCT
Default: 10		 OLAP Sort Buffer Size Percentage
TBD
_OLAP_SORT_BUFFER_SIZE
Default: 262144		 OLAP Sort Buffer Size
TBD
_OPTIMIZER_DB_BLOCKS_BUFFER
Default: 0		 Optimizer value for _db_blocks_buffers
TBD
_PLSQL_DUMP_BUFFER_EVENTS
Default: <NULL>		 Conditions upon which the PL/SQL circular buffer is dumped
TBD
_PX_BUFFER_TTL
Default: 30		 TTL for px mesg buffers in seconds
TBD
_QUEUE_BUFFER_MAX_DUMP_LEN
Default: 65536		 Maximum number of bytes to dump to trace file for queue buffer dump
TBD
_RECOVERABLE_RECOVERY_MAX_INFLUX_BUFFERS
Default: 100000		 Recoverable recovery number of influx buffers limit
TBD
_SESSION_PREDICTION_FAILOVER_BUFFER
Default: 0		 Session prediction failover buffer
TBD
_SKGXP_UDP_TIMED_WAIT_BUFFERING
Default: 1024		 Diagnostic log buffering space (in bytes) for timed wait (0 means unbufferd
TBD
_TRACE_BUFFER_WAIT_TIMEOUTS
Default: 0		 Trace buffer busy wait timeouts
TBD
_TRACE_BUFFERS
Default: ALL		 256 trace buffer sizes per process
TBD
_UTS_TRACE_BUFFER_SIZE
Default: 0		 Trace disk buffer size
TBD
_XTBIGDATA_MAX_BUFFERSIZE
Default: 10240		 Maximum size of IO Buffers for exadoop external tables (in KB)
TBD
_XTBUFFER_SIZE
Default: 0		 Buffer size in KB needed for populate/query operation
TBD
 
Compression
_ADVANCED_INDEX_COMPRESSION_CMP _OPTIONS
Default: 0		 Advanced index compression cmp options
_advanced_index_compression_cmp_options=1
_ADVANCED_INDEX_COMPRESSION_OPT _OPTIONS
Default: 0		 Advanced index compression opt options
_advanced_index_compression_opt_options=1
_ADVANCED_INDEX_COMPRESSION_OPTIONS
Default: 0		 Advanced index compression options
_advanced_index_compression_options=11
_ADVANCED_INDEX_COMPRESSION_OPTIONS _VALUE
Default: 0		 Advanced index compression options2
_advanced_index_compression_options_value=1
_ADVANCED_INDEX_COMPRESSION_RECMP _CRSZ
Default: 10		 Advanced index compression limit recomp cr
_advanced_index_compression_recmp_crsz=12
_ADVANCED_INDEX_COMPRESSION_RECMP _CUSZ
Default: 90		 Advanced index compression limit recomp cu
_advanced_index_compression_recmp_cusz=100
_ADVANCED_INDEX_COMPRESSION_RECMP _NPRG
Default: 10		 Advanced index compression limit recomp pu
_advanced_index_compression_recmp_nprg=12
_ADVANCED_INDEX_COMPRESSION_TRACE
Default: 0		 Advanced index compression trace
_advanced_index_compression_trace=1
_ADVANCED_INDEX_COMPRESSION_TST _OPTIONS
Default: 0		 Advanced index compression test options
_advanced_index_compression_tst_options=1
_ADVANCED_INDEX_COMPRESSION_UMEM _OPTIONS
Default: 2147483647		 Advanced index compression umem options
_advanced_index_compression_umem_options=1431655765
_ARCH_COMPRESS_CHECKSUMS
Default: FALSE		 Enable/disable row checksums for archive compressed blocks
TBD
_ARCH_COMPRESSION
Default: TRUE		 Archive compression enabled
TBD
_COLUMN_COMPRESSION_FACTOR
Default: 0		 Column compression ratio
TBD
_COMPRESSION_ADVISOR
Default: 0		 Compression advisor
TBD
_COMPRESSION_CHAIN
Default: 90		 Percentage of chained rows allowed for Compression
TBD
_COMPRESSION_COMPATIBILITY
Default: 21.0.0		 Compression compatibility
TBD
_DISABLE_INITIAL_BLOCK_COMPRESSION
Default: FALSE		 Disable initial block compression
TBD
_FORCE_ARCH_COMPRESS
Default: 0		 Archive Compress all newly created compressed tables
TBD
_FORCE_HSC_COMPRESS
Default: FALSE		 Compress all newly created tables
TBD
_FORCE_OLTP_COMPRESS
Default: FALSE		 OLTP Compress all newly created compressed tables
TBD
_FORCE_PARTIAL_COMPRESS
Default: FALSE		 Force using OLTP Partial Compression
TBD
_FORCE_SYS_COMPRESS
Default: TRUE		 Sys compress
TBD
_GC_FUSION_COMPRESSION
Default: 1024		 Compress fusion blocks if there is free space
TBD
_HPK_COMPRESSION_RANGE
Default: 5		 HPK compression range
TBD
_KDLXP_LOBCOMPRESS
Default: FALSE		 Enable lob compression - only on SecureFiles
TBD
LM_BATCH_COMPRESSION_THRESHOLD
Default: 0		 GES threshold to start compression on batch messages
TBD
_LM_COMPRESSION_SCHEME_LIB
Default: zlib		 GES compression scheme
TBD
_OLTP_COMPRESS_DBG
Default: 0		 OLTP compression debug
TBD
_OLTP_COMPRESSION
Default: TRUE		 OLTP compression enabled
TBD
_OLTP_COMPRESSION_GAIN
Default: 10		 OLTP compression gain
TBD
_REDO_TRANSPORT_COMPRESS_ALL
Default: TRUE		 Is ASYNC LNS compression allowed?
TBD
_UNUSED_BLOCK_COMPRESSION
Default: TRUE		 Enable unused block compression
TBD
_USER_PLATFORM_COMPRESSION_LIB
Default: TRUE		 Enable platform optimized compression implementation
TBD
_XT_DEF_COMPRESSION_RATIO
Default: 4		 Default compression ratio for external table data files
TBD
 
Container Database
_APPQOS_CDB_SETTING
Default: 0		 CDB Performance Class Setting
TBD
_ARRAY_CDB_VIEW_ENABLED
Default: TRUE		 Array mode enabled for CDB views
TBD
_CDB_COMPATIBLE
Default: TRUE		 CDB Compatible
TBD
_CDB_CROSS_CONTAINERS
Default: 65535		 Debug flag for cross container operations
TBD
_CDB_DISASLE_PDB_LIMIT
Default: FALSE		 CDB Compatible
TBD
_CDB_FLEET_SYNC_TIMEOUT
Default: 10		 Time in minutes to wait for sync of stub entry in CDB Fleet
TBD
_CDB_PORT
Default: 0		 Port number for CDB
TBD
_CDB_RAC_AFFINITY
Default:  TRUE		 RAC affinity for parallel CDB operations
TBD
_CDB_SPEICAL_OLD_XPLAN
Default: TRUE		 Display old-style plan for CDB special fixed table
TBD
_CDB_SPFILE_INHERIT
Default: FALSE		 Inherit CDB Spfile enabled/disabled in a PDB
TBD
_CDB_VIEW_NO_SKIP_MIGRATE
Default: FALSE		 Do not skip OPEN MIGRATE PDBs from results of CONTAINERS()
TBD
_CDB_VIEW_NO_SKIP_RESTRICTED
Default: FALSE		 Do not skip RESTRICTED mode PDBs from results of CONTAINERS()
TBD
_CDB_VIEW_PARALLEL_DEGREE
Default: 65535		 65535 Parallel degree for a CDB view query
TBD
_CDB_VIEW_PREFETCH_BATCH_SIZE
Default: 200		 Batch Size for Prefetch for a CDB view query
TBD
_CDB_VIEW_RC_SHELFLIFE
Default: 30		 Result Cache Shelf life for a CDB view query
TBD
_CDB_VIEW_RECURSIVE_PX_ENABLED
Default: TRUE		 Enable parallelism of recursive SQL under CONTAINERS()
TBD
_DIAG_CDB_LOGGING
Default: short		 Format for CDB Annotation
TBD
_DISABLE_CDB_VIEW_RC_INVALIDATION
Default: FALSE		 Disable Result Cache invalidation for CDB View results
TBD
_ENALE_CDB_UPGRADE_CAPTURE
Default: FALSE		 _enable_cdb_upgrade_capture FALSE Enable capture of CDB upgrade
TBD
_EXCLUDE_SEED_CDB_VIEW
Default: TRUE		 _exclude_seed_cdb_view TRUE exclude PDB$SEED from CDB View Result
TBD
_INTRA_CDB_DBLINK
Default: FALSE		 Enable intra CDB implicit dblink
TBD
_MULTIPLE_CHAR_SET_CDB
Default: TRUE		 Multiple character sets enabled in CDB
TBD
_PARTITION_CDB_VIEW_ENABLED
Default: TRUE		 Partitioned cdb view evaluation enabled
TBD
_PDB_MASK_CDB_INFO
Default: FALSE		 Enable masking CDB information within a PDB
TBD
_PRED_PUS_CDB_VIEW_ENABLED
Default: TRUE		 Predicate pushdown enabled for CDB views
TBD
_PX_CDB_VIEW_ENABLED
Default: TRUE		 Parallel cdb view evaluation enabled
TBD
_PX_CDB_VIEW_JOIN_ENABLED
Default: TRUE		 Disable parallelism cap on CDB view
TBD
_ROWSETS_CDB_VIEW_ENABLED
Default: TRUE		 Rowsets enabled for CDB views
TBD
 
Data Guard
_ACTIVE_STANDBY_FAST_RECONFIGURATION
Default: TRUE		 If TRUE optimizes DLM reconfiguration for active/standby operations
TBD
_ADG_ADT_REDIRECT_APPLY_LAG_THRESHOLD
Default: 12000		 Maximum centi-secends of apply lag threshold
TBD
_ADG_ADT_REDIRECT_CATCHUP_WAIT_TIME
Default: 12000		 Maximum centi-secends for standby to catch up
TBD
_ADG_AUTO_CLOSE_PDB
Default: TRUE		 Recovery auto close PDB upon PDB drop/unplug/rename marker
TBD
_ADG_COUNT_BEYOND_LIMIT
Default: 0		 Count the total number of objects if beyond redo marker length
TBD
_ADG_DEFER_SEGSTAT
Default: TRUE		 Defer the segment statistics update on standby.
TBD
_ADG_DISTRIBUTED_LOCKMASTER
Default: FALSE		 Standby runs under ADG distributed lockmaster mode
TBD
_ADG_INFLUX_QSCN_GAP
Default: 0 		Maximum time gap between influx scn and qscn update in seconds
TBD
_ADG_INSTANCE_RECOVERY
Default: TRUE		 Enable ADG instance recovery
TBD
_ADG_OBJECTLOCK_ATTEMPTS
Default: 2 		Maximum attempts for objectlock get on ADG
TBD
_ADG_OBJECTLOCK_MAXNUM
Default: 1000 		Maximum limit of the objectlock number on ADG
TBD
_ADG_OBJECTLOCK_TIMEOUT
Default: 0 		timeout for objectlock get on ADG in centiseconds
TBD
_ADG_PARSELOCK_TIMEOUT
Default: 0 		timeout for parselock get on ADG in centiseconds
TBD
_ADG_PARSELOCK_TIMEOUT_SLEEP
Default: 100 		sleep duration after a parselock timeout on ADG in milliseconds
TBD
_ADG_REDIRECT_UPD_TO_PRIMARY_MAX_RETRIES
Default: 500		 max retries for ADT redirect to Primary from ADG
TBD
_ALLOW_CONVERT_TO_STANDBY
Default: FALSE		 Allow convert to standby to go through
TBD
_ALLOW_DROP_SNAPSHOT_STANDBY_GRSP
Default: FALSE		 Allow dropping snapshot standby guaranteed restore point
TBD
_ALTER_ADG_REDIRECT_BEHAVIOR
Default: none		 Alter ADG's Redirection behavior
TBD
_CAUSAL_STANDBY_WAIT_TIMEOUT
Default: 20		 Causal standby wait timeout
TBD
_ADG_BROKER_TRACE_LEVEL
Default: <NULL>		 Data Guard Broker trace level
TBD
_DG_CF_CHECK_TIMER
Default: 15		 Data Guard controlfile check timer
TBD
_DG_CORRUPT_REDO_LOG
Default: 0		 Corrupt redo log validation during archivals
TBD

_enable_single_dgprepare FALSE Disable concurrent PREPAREs in same disk group
_FLUSH_REDO_TO_STANDBY
Default: 0		 Flush redo to standby test parameter
TBD
_INMEMORY_ADG_BATCHED_FLUSH
Default: TRUE		 If true, batched flush is performed
TBD
_INMEMORY_ADG_JOURNAL_QUOTA
DEFAULT: FALSE		 If true, throttled mining is performed under space pressure
TBD
_INMEMORY_ADG_PARALLEL_FLUSH
Default: TRUE		 If true, parallel flush is performed
TBD
_INMEMORY_ADG_PERIODIC_SORT
Default: FALSE		 If true, periodic sort is performed
TBD
_INMEMORY_ADG_QUIECE_TIMEOUT
Default: 2		 Timeout for getting ZQ enqueue
TBD
_NOLOGGING_STANDBY_COLD_BUFFER_TIMEOUT
Default: 500		 Centisecs recovery wait for buffer not sent by direct load client in Nologging Standby Data Availability mode
TBD
_NOLOGGING_STANDBY_DTC_EXPIRE
Default: 600		 The number of seconds a Data Transfer Cache buffer may remain unclaimed
TBD
_NOLOGGING_STANDBY_FETCH_DISABLE
Default: FALSE		 Controls whether invalid block ranges are fetched during recovery
TBD
_NOLOGGING_STANDBY_REFETCH_DISABLE
Default: FALSE		 Controls fetching of pre-existing invalid block ranges during standby recovery
TBD
_PREFERED_STANDBY
Default: <NULL>		 Standby db_unique_name preferred for KRB operations
TBD
_READABLE_STANDBY_SYNC_INTERVAL
Default: 0		 Readable standby recovery global sync interval
TBD
_READABLE_STADBY_SYNC_TIMEOUT
Default: 10		 Readable standby query scn sync timeout
TBD
_REMOVE_INACTIVE_STANDBY_TDE_MASTER_KEY
Default: FALSE		 Remove Inactive Standby TDE Master Key
TBD
_REMOVE_STDBY_OLD_KEY_AFTER_CHECKPOINT
_SCN
Default: TRUE		 Remove standby old key after checkpoint SCN
TBD
_STANDBY_CAUSAL_HEARTBEAT_TIMEOUT
Default: 		Readable standby causal heartbeat timeout
TBD
_STANDBY_FLUSH_MODE
Default: 		Standby flush mode
TBD
_STANDBY_IMPLICIT_RCV_TIMEOUT
Default: 		Minutes to wait for redo during standby implicit recovery
TBD
_STANDBY_NEWKEY_KEYSTORE_LOCATION
Default: 		Location of keystore on standby having new key
TBD
_STANDBY_SWITCHOVER_TIMEOUT
Default: 		Number of secords for standby switchover enqueue timeout
TBD
_SWITCHOVER_THROUGH_CASCADE
Default: TRUE		 Enable switchover through farsync
TBD
_SWITCHOVER_TIMEOUT
Default: 0		 Switchover timeout in minutes
TBD
_SWITCHOVER_TO_STANDBY_OPTION
Default: OPEN_ALL_IGNORE_SESSIONS		 Option for graceful switchover to standby
TBD
_SWITCHOVER_TO_STADBY_SWITCH_LOG
Default: FALSE		 Switchover to standby switches log for open redo threads
TBD
_TEMP_UNDO_DISABLE_ADG
Default: FALSE		 Is temp undo disabled on ADG
TBD
__DG_BROKER_SERVICE_NAMES
Default: <NULL>		 Service names for broker use
TBD
 
Data Pump
_DATAPUMP_COMPRESSBAS_BUFFER_SIZE
Default: 0		 Specifies buffer size for BASIC compression algorithm
TBD
_DATAPUMP_CONV_PGA_LIM
Default: 0		 PGA limit for Data Pump conventional path bind array size
TBD
_DATAPUMP_GATHER_STATS_ON_LOAD
Default: FALSE		 Gather table statistics during Data Pump load rather than importing statistics from the dump file
TBD
_DATAPUMP_INHERIT_SVCNAME
Default: TRUE		 Inherit and propagate service name throughout job
TBD
_DATAPUMP_METADATA_BUFFER_SIZE
Default: 131072		 Specifies buffer size for metadata file I/O
TBD
_DATAPUMP_TABLEDATA_BUFFER_SIZE
Default: 262144		 Specifies buffer size for table data file I/O
TBD
 
Database Blocks
_DB_BLOCK_ADJCHECK
Default: TRUE		 Adjacent cache buffer checks - low blkchk overwrite parameter
TBD
_DB_BLOCK_ADJCHK_LEVEL
Default: 0		 Adjacent cache buffer check level
TBD
_DB_BLOCK_ALIGN_DIRECT_READ
Default:TRUE		 Align Direct Reads
TBD
_DB_BLOCK_BAD_WRITE_CHECK
Default:FALSE		 Enable bad write checks
TBD
_DB_BLOCK_BUFFERS
Default:301532		 Number of database blocks cached in memory: hidden parameter
TBD
_DB_BLOCK_CACHE_HISTORY_LRU
Default: FALSE		 Buffer header tracing for lru operations
TBD
_DB_BLOCK_CACHE_PROTECT
Default: FALSE		 Protect database blocks (for debugging only)
TBD
_DB_BLOCK_CACHE_PROTECT_INTERNAL
Default: 0		 Protect database blocks (for internal use only)
TBD
_DB_BLOCK_CHECK_FOR_DEBUG
Default: FALSE		 Check more and dump block before image for debugging
TBD
_DB_BLOCK_CHECK_OBJTYP
Default: TRUE		 Check objd and typ on cache disk read
TBD
_DB_BLOCK_CHUNKIFY_NCMBR
Default: FALSE		 Chunkify non-contiguous multi block reads
TBD
_DB_BLOCK_CORRUPTION_RECOVERY_THRESHOLD
Default: 5		 Threshold number of block recovery attempts
TBD
_DB_BLOCK_DO_FULL_MBREADS
Default: FALSE		 Do full block read even if some blocks are in cache
TBD
_DB_BLOCK_HASH_BUCKETS
Default: 1048576		 Number of database block hash buckets
TBD
_DB_BLOCK_HASH_LATCHES
Default: 8192		 Number of database block hash latches
TBD
_DB_BLOCK_HEADER_GUARD_LEVEL
Default: 0		 Number of extra buffer headers to use as guard pages
TBD
_DB_BLOCK_HI_PRIORITY_BATCH_SIZE
Default: 0		 Fraction of writes for high priority reasons
TBD
_DB_BLOCK_ITERATIONS_FOR_RM
Default: 2000		 Number of blocks to reduce every iteration for RM
TBD
_DB_BLOCK_KNOWN_CLEAN_PCT
Default: 2		 Initial Percentage of buffers to maintain known clean
TBD
_DB_BLOCK_LRU_LATCHES
Default: 36		 Number of lru latches
TBD
_DB_BLOCK_MAX_CR_DBA
Default: 6		 Maximum Allowed Number of CR buffers per DBA
TBD
_DB_BLOCK_MAX_SCAN_PCT
Default: 40		 Percentage of buffers to inspect when looking for free
TBD
_DB_BLOCK_MED_PRIORITY_BATCH_SIZE
Default: 0		 Fraction of writes for medium priority reasons
TBD
_DB_BLOCK_NUMA
Default: 1		 Number of NUMA nodes
TBD
_DB_BLOCK_PREFETCH_FAST_LONGIUMPS_ENABLED
Default: TRUE		 Batched IO enable fast longjumps
TBD
_DB_BLOCK_PREFETCH_LIMIT
Default: 0		 Prefetch limit in blocks
TBD
_DB_BLOCK_PREFETCH_OVERRIDE
Default: 0		 Prefetch force override in blocks
TBD
_DB_BLOCK_PREFETCH_PRIVATE_CACHE_ENABLED
Default: TRUE		 Batched IO enable private cache
TBD
_DB_BLOCK_PREFETCH_QUOTA
Default: 10		 Prefetch quota as a percent of cache size
TBD
_DB_BLOCK_PREFETCH_SKIP_READING_ENABLED
Default: TRUE		 Batched IO enable skip reading buffers
TBD
_DB_BLOCK_PREFETCH_WASTED_THRESHOLD_PERC
Default: 2		 Allowed wasted percent threshold of prefetched size
TBD
_DB_BLOCK_SCANDEPTH_FOR_RM
Default: 20		 Number of blocks to reduce every iteration for RM
TBD
_DB_BLOCK_TABLE_SCAN_ BUFFER_SIZE
Default: 4194304		 Size of shared table scan read buffer
TBD
_DB_BLOCK_TEMP_REDO
Default: FALSE		 Generate redo for temp blocks
TBD
_DB_BLOCK_TRACE_PROTECT
Default: FALSE		 Trace buffer protect calls
TBD
_DB_BLOCK_VLM_CHECK
Default: FALSE		 Check for mapping leaks (debugging only)
TBD
_DB_BLOCK_VLM_LEAK_THRESHOLD
Default: 4		 Threshold for allowable mapping leaks
TBD
_DB_BLOCK__PER_HASH_LATCH
Default: <NONE>		 Number of blocks per hash latch
TBD
_OPTIMIZER_DB_BLOCKS_BUFFERS
Default: 0		 Optimizer value for _db_blocks_buffers
TBD
 
Database Cache
_DB_CACHE_ADVICE_HASH_LATCH_MULTIPLE
Default: 16		 Cache advisory hash latch multiple
TBD
_DB_CACHE_ADVICE_MAX_SIZE_FACTOR
Default: 2		 Cache advisory maximum multiple of current size to similate (sp?)
TBD
_DB_CACHE_ADVICE_SAMPLE_FACTOR
Default: 4		 Cache advisory sampling factor
TBD
_DB_CACHE_ADVICE_SANITY_CHECK
Default: FALSE		 Cache simulation sanity check
TBD
_DB_CACHE_BLOCK_READ_STACK_TRACE
Default: 0		 Dump short call stack for block reads
TBD
_DB_CACHE_BLOCK_READ_STACK_TRACE_WHERE1
Default: 0		 Dump short call stack for block reads just for where1
TBD
_DB_CACHE_BLOCK_READ_STACK_TRACE_WHERE2
Default: 0		 Dump short call stack for block reads just for where2
TBD
_DB_CACHE_BLOCK_READ_STACK_TRACE_WHERE3
Default: 0		 Dump short call stack for block reads just for where3
TBD
_DB_CACHE_CRX_CHECK
Default: FALSE		 Check for costly crx examination functions
TBD
_DB_CACHE_MAX_SZ
Default: 0		 Database cache maximum size
TBD
_DB_CACHE_MISS_CHECK_LES
Default: FALSE		 Check LEs after cache miss
TBD
_DB_CACHE_MMAN_LATCH_CHECK
Default: FALSE		 Check for wait latch get under MMAN ops in KCB
TBD
_DB_CACHE_PRE_WARM
Default: TRUE		 Buffer Cache Pre-Warm Enabled : hidden parameter
TBD
_DB_CACHE_PROCESS_CR_PIN_MAX
Default: 2147483647		 Maximum number of cr pins a process may have
TBD
_DB_CACHE_SILICON_SECURED_MEMORY
Default: TRUE		 Enable silicon secured memory
TBD
_DB_CACHE_WAIT_DEBUG
Default: 0		 Trace new kslwaits
TBD
_DB_CACHE_XMEM_SIZE
Default: 0		 Size of extended memory data area for buffer cache DEFAULT pool
TBD
 
DIAGNOSTICS
_DIAG_ADL_DYN_ALLOC
Default: TRUE		 Enable Diag Alert Dynamic Allocation
TBD
_DIAG_ADR_AUTO_PURGE
Default: TRUE		 Enable/disable ADR MMON Auto Purging
TBD
_DIAG_ADR_ENABLED
Default: TRUE		 Parameter to enable/disable Diag ADR
TBD
_DIAG_ADR_TEST_PARAM
Default: 0		 Test parameter for Diagnosability
TBD
_DIAG_ADR_TRACE_DEST
Default: $ORACLE_BASE/DIAG/RDBMS/<db_name>/ <instance_name/trace/ 		Diagnosability trace directory path
TBD
_DIAG_ALERT_ROOT_ANNOTATE
Default: FALSE		 Enable annotation for alert log entries from root
TBD
_DIAG_ARB_BEFORE_KILL
Default: FALSE		 Dump diagnostics before killing unresponsive ARBs
TBD
_DIAG_ATTN_LOG_FORMAT_ERROR
Default: <NULL>		 Attention Log Error Entry format
TBD
_DIAG_ATTN_LOG_FORMAT_STANDARD
Default: <NULL>		 Attention Log Standard Entry format
TBD
_DIAG_BACKWARD_COMPAT
Default: TRUE		 Backward Compatibility for Diagnosability
TBD
_DIAG_CC_ENABLED
Default: TRUE		 Parameter to enable/disable Diagostic Call Context
TBD
_DIAG_CDB_LOGGING
Default: SHORT		 Format for CDB Annotation
TBD
_DIAG_CONF_CAP_ENABLED
Default: TRUE		 Parameter to enable/disable Diagnostic Configuration Capture
TBD
_DIAG_CRASHDUMP_LEVEL
Default: 10		 Parameter for systemstate dump level, used by DIAG during crash
TBD
_DIAG_DAEMON
Default: TRUE		 Start DIAG daemon
TBD
_DIAG_DDE_ASYNC_AGE_LIMIT
Default: 300		 diag dde async actions: message age limit (in seconds)
TBD
_DIAG_DDE_ASYNC_CPUTIME_LIMIT
Default: 300		 diag dde async actions: action cputime limit (in seconds)
TBD
_DIAG_DDE_ASYNC_MODE
Default: 1		 diag dde async actions: dispatch mode
TBD
_DIAG_DDE_ASYNC_MSG_CAPACITY
Default: 1024		 diag dde async actions: message buffer capacity
TBD
_DIAG_DDE_ASYNC_MSGS
Default: 50		 diag dde async actions: number of preallocated message buffers
TBD
_DIAG_DDE_ASYNC_PROCESS_RATE
Default: 5		 diag dde async actions: message processing rate - per loop
TBD
_DIAG_DDE_ASYNC_RUNTIME_LIMIT
Default: 900		 diag dde async actions: action runtime limit (in seconds)
TBD
_DIAG_DDE_ASYNC_SLAVES
Default: 5		 diag dde async actions: max number of concurrent slave processes
TBD
_DIAG_DDE_ENABLE
Default: TRUE		 DDE handling of critical errors
TBD
_DIAG_DDE_FC_ENBLED
Default: TRUE		 Parameter to enable/disable Diag Flood Control
TBD
_DIAG_DDE_FC_IMPLICIT_TIME
Default: 0		 Override Implicit Error Flood Control time parameter
TBD
_DIAG_DDE_FC_MACRO_TIME
Default: 0		 Override Macro Error Flood Control time parameter
TBD
_DIAG_DDE_INC_PROC_DELAY
Default: 1		 Minimum delay between two MMON incident sweeps (minutes)
TBD
_DIAG_DIAGNOSTICS
Default: TRUE		 Turn off diag diagnostics
TBD
_DIAG_DUMP_REQUEST_DEBUG_LEVEL
Default: 1		 DIAG dump request debug level (0-2)
TBD
_DIAG_DUMP_TIMEOUT
Default: 30		 Timeout parameter for SYNC dump
TBD
_DIAG_ENABLE_STARTUP_EVENTS
Default: FALSE		 Enable events in instance startup notifiers
TBD
_DIAG_HM_RC_ENABLED
Default: TRUE		 Parameter to enable/disable Diag HM Reactive Checks
TBD
_DIAG_HM_TC_ENABLED
Default: FALSE		 Parameter to enable/disable Diag HM Test(dummy) Checks
TBD
_DIAG_LARGE_PACKAGES
Default: TRUE		 DIA* large packets support
TBD
_DIAG_PATCH_CAP_ENABLED
Default: TRUE		 Parameter to enable/disable Diag Patch Configuration Capture
TBD
_DIAG_PDB_CONTROL
Default: 0		 DIAG PDB Space Management Control Parameter
TBD
_DIAG_PDB_PURGE_TARGET
Default: 90		 Controls target percentage for ADR PDB Auto Purge Operation
TBD
_DIAG_PDB_PURGE_THRESHOLD
Default: 97		 Controls threshold for ADR PDB Auto Purge Operation
TBD
_DIAG_PROC_ENABLED
Default: TRUE		 Enable hung process diagnostic API
TBD
_DIAG_PROC_MAX_TIME_MS
Default: 30000		 Hung process diagnostic API max wait time in milliseconds
TBD
_DIAG_PROC_STACK_CAPTURE_TYPE
Default: 1		 Hung process diagnostic API stack capture type
TBD
_DIAG_TEST_SEG_REINC_MODE
Default: FALSE		 Sets trace segmentation to be in reincarnation mode
TBD
_DIAG_UTS_CONTROL
Default: 0		 UTS control parameter
TBD
_DIAG_VERBOSE_ERROR_ON_INIT
Default: 0		 Allow verbose error tracing on diag init
TBD
_DIAG_XM_ENABLED
Default: FALSE		 If TRUE, DIAG allows message exchanges across DB/ASM boundary
TBD
 
DISTRIBUTED REPLICATION
_EVT_SYSTEM_EVENT_PROPAGATION
Default: TRUE		 Disable system event propagation
TBD
_IMMEDIATE_COMMIT_PROPAGATION
Default: TRUE		 If TRUE, propagate commit SCN immediately
TBD
 
EXADATA
_ALLOW_CELL_SMART_SCAN_ATTR
Default: TRUE		 Allow checking smart_scan_capable Attr
TBD
_AUTO_MANAGE_EXADATA_DISKS
Default: TRUE		 Automate Exadata disk management
TBD
_BLOOM_PREDICATE_OFFLOAD
Default: TRUE		 Enables or disables bloom filter predicate offload to cells
TBD
_CELL_FAST_FILE_CREATE
Default: TRUE		 Allow optimized file creation path for Cells
TBD
_CELL_FAST_FILE_RESTORE
Default: TRUE		 Allow optimized RMAN restore for Cells
TBD
_CELL_FILE_FORMAT_CHUNK_SIZE
Default: 0		 Cell file format chunk size in MB
TBD
_CELL_INDEX_SCAN_ENABLED
Default: TRUE		 Enable CELL processing of index FFS
TBD
_CELL_MATERIALIZE_ALL_EXPRESSIONS
Default: FALSE		 Force materialization of all offloadable expressions on the cells
TBD
_CELL_MATERIALIZE_VIRTUAL_COLUMNS
Default: TRUE		 Enable offload of expressions underlying virtual columns to cells
TBD
_CELL_OBJECT_EXPIRATION_HOURS
Default: 24		 Flashcache object expiration timeout
TBD
_CELL_OFFLOAD_BACKUP_COMPRESSION
Default: TRUE		 enable offload of backup compression to cells
TBD
_CELL_OFFLOAD_CAPABILITIES_ENABLED
Default: 1		 Specifies capability table to load
TBD
_CELL_OFFLOAD_COMPEX_PROCESSING
Default: TRUE		 Enable complex SQL processing offload to cells
TBD
_CELL_OFLOAD_EXPRESSIONS
Default: TRUE		 Enable offload of expressions to cells
TBD
_CELL_OFFLOAD_GRAND_TOTAL
Default: TRUE		 Allow offload of grand total aggregations
TBD
_CELL_OFFLOAD_HYBRID_PROCESSING
Default: TRUE		 Enable hybrid SQL processing offload to cells
TBD
_CELL_OFFLOAD_HYBRIDCOLUMNAR
Default: TRUE		 Query offloading of hybrid columnar compressed tables to exadata
TBD
_CELL_OFFLOAD_PREDICATE_REORDERING
_ENABLE
Default: FALSE		 Enable out-of-order SQL processing offload to cells
TBD
_CELL_OFFLOAD_SYS_CONTEXT
Default: TRUE		 Enable offload of SYS_CONTEXT evaluation to cells
TBD
_CELL_OFFLOAD_TIMEZONE
Default: TRUE		 Enable timezone related SQL processing offload to cells
TBD
_CELL_OFFLOAD_VECTOR_GROUPBY
Default: TRUE		 Enable SQL processing offload of vector group by
TBD
_CELL_OFFLOAD_VECTOR_GROUPBY_FACT_KEY
Default: TRUE		 Enable cell offload of vector group by with fact grouping keys
TBD
_CELL_OFFLOAD_VECTOR_GROUPBY_FORCE
Default: FALSE		 Force offload of vector group by
TBD
_CELL_OFFLOAD_VECTOR_GROUBY_WITHNOJOIN
Default: TRUE		 Allow offload of vector group by without joins
TBD
_CELL_OFFLOAD_VIRTUAL_COLUMNS
Default: TRUE		 Enable offload of predicates on virtual columns to cells
TBD
_CELL_RANGE_SCAN_ENABLED
Default: TRUE		 Enable CELL processing of index range scans
TBD
_CELL_STORIDX_MINMAX_ENABLED
Default: TRUE		 Enable Storage Index Min/Max optimization on the cells
TBD
_CELL_STORIDX_MODE
Default: EVA		 Cell Storage Index mode
TBD
_CELLCACHE_CLAUSE_DEFAULT
Default: Default		 Cellcache clause for new tables
TBD
_CELLCACHE_DEFAULT_FLAGS
Default: 2		 Default flags based on cellcache_clause_default
TBD
_CELLCACHE_DEFAULT_NEW
Default: FALSE		 Force cellcache on new tables
TBD
_CLUSTER_FLASH_CACHE_SLAVE_FILE
Default: <NULL>		 Cluster flash cache slave file for default block size
TBD
_CLUSTER_FLASH_CACHE_SLAVE_SIZE
Default: 0		 Cluster flash cache slave file size for default block size
TBD
_CONTROLFILE_CELL_FLASH_CACHING
Default: 3		 Flash cache hint for control file accesses
TBD
_DB_CHECK_CELL_HINTS
Default: FALSE		 Undocumented
TBD
_DB_16K_FLASH_CACHE_FILE
Default: <NULL>		 Flash cache file for 16k block size
TBD
_DB_16K_FLASH_CACHE_SIZE
Default: 0		 Flash cache size for _db_16k_flash_cache_file
TBD
_DB_2K_FLASH_CACHE_FILE
Default: <NULL>		 Flash cache file for 2k block size
TBD
_DB_2K_FLASH_CACHE_SIZE
Default: 0		 Flash cache size for _db_2k_flash_cache_file
TBD
_DB_32K_FLASH_CACHE_FILE
Default: <NULL>		 Flash cache file for 32k block size
TBD
_DB_32K_FLASH_CACHE_SIZE
Default: 0		 Flash cache size for _db_32k_flash_cache_file
TBD
_DB_4K_FLASH_CACHE_FILE
Default: <NULL>		 Flash cache file for 4k block size
TBD
_DB_4K_FLASH_CACHE_SIZE
Default: 0		 Flash cache size for _db_4k_flash_cache_file
TBD
_DB_8K_FLASH_CACHE_FILE
Default: <NULL>		 Flash cache file for 8k block size
TBD
_DB_8K_FLASH_CACHE_SIZE
Default: 0		 Flash cache size for _db_8k_flash_cache_file
TBD
_DB_FLASH_CACHE_DISABLE_WRITE_BATCHSIZE
Default: 4096		 Flash cache disable writes processing batch size
TBD
_DB_FLASH_CACHE_ENCRYPTION
Default: FALSE		 Set enable/disable flash cache encryption
TBD
_DB_FLASH_CACHE_FORCE_REPLENISH_LIMIT
Default: 8		 8 Flash cache force replenish lower limit in buffers
TBD
_DB_FLASH_CACHE_KEEP_LIMIT
Default: 80		 Flash cache keep buffer upper limit in percentage
TBD
_DB_FLASH_CACHE_MAX_LATENCY
Default: 400		 Flash cache maximum latency allowed in 10 milliseconds
TBD
_DB_FLASH_CACHE_MAX_OUTSTANDING_WRITES
Default: 32		 Flash cache maximum outstanding writes allowed
TBD
_DB_FLASH_CACHE_MAX_READ_RETRY
Default: 3		 Flash cache max read retry
TBD
_DB_FLASH_CACHE_MAX_SLOW_IO
Default: 3		 Flash cache maximum slow io allowed
TBD
_DB_FLASH_CACHE_SLOW_IO_ADJUSTMENT
_INTERVAL
Default: 3600		 Decrement interval
TBD
_DB_FLASH_CACHE_WRITE_LIMIT
Default: 1		 Flash cache write buffer upper limit in percentage
TBD
_DISABLE_CELL_OPTIMIZED_BACKUPS
Default: FALSE		 Disable cell optimized backups
TBD
_ENABLE_FLASH_LOGGIN
Default: TRUE		 Enable Exadata Smart Flash Logging
TBD
_ENABLE_OFFLOADED_WRITES
Default: FALSE		 Enable offloaded writes for Unit Test
TBD
_EXADATA_FEATURE_ON
Default: FALSE		 Exadata Feature On
Range of values: {TRUE | FALSE}
_exadata_feature_on=TRUE
_GC_SERVE_FROM_FLASH_CACHE
Default: FALSE		 If TRUE, try to serve a flash cache buffer
TBD
_GCS_CLUSTER_FLASH_CACHE_MODE
Default: 0		 Cluster flash cache mode
TBD
_GCS_CLUSTER_FLASH_CACHE_PERSISTENCY
Default: FALSE		 Enable cluster flash cache persistency (FALSE = disable (default), TRUE = enable
TBD
_GCS_FLASH_CACHE_MODE
Default: 0 		_gcs_flash_cache_mode 0 flash cache mode
TBD
_HCS_DISABLE_CELL_QRY_ATR_PRUNE_OPT
Default: FALSE		 _hcs_disable_cell_qry_atr_prune_opt FALSE apply attribute prune optimization to cell query
TBD
_HCS_DISABLE_CELL_QRY_M_PRUNE_OPT
Default: FALSE		 _hcs_disable_cell_qry_lvl_prune_opt FALSE apply level prune optimization to cell query
TBD
_HCS_DISABLE_CELL_QRY_MEAS_PRUNE_OPT
Default: FALSE		 Apply measure prune optimization to cell query
TBD
_HCS_DISABLE_CELL_QRY_MV_CACHE_OPT
Default: FALSE		 Apply mv cache optimization to cell query
TBD
_HCS_DISABLE_CELL_QRY_NO_CALC_NAV_OPT
Default: FALSE		 Apply no calc navigation optimization to cell query
TBD
_HCS_DISABLE_CELL_QRY_NO_OUT_DATA_OPT
Default: FALSE		 Apply no output data optimization to cell query
TBD
_HCS_DISABLE_CELL_QRY_TMPLS
Default: FALSE		 No cell query templates for optimization
TBD
_HCS_DISABLE_OPT_CELL_QRY
Default: FALSE		 Optimize cell query
TBD
_KEY_VECTOR_OFFLOAD
Default: predicate		 Controls key vector offload to cells
TBD
_KXDBIO_DISABLE_OFFLOAD_OPCODE
Default: 0		 Disable offload for the set opcodes. Value is a Bitmap of 0x00000001 - disable cell to cell data copy offload 0x00000002 - disable disk scrubbing offload to cell 0 x00000004 - disable offloaded writes to cell
TBD
 
FILE LOCATIONS
_DIAG_ADR_TRACE_DEST
Default: $ORACLE_BASE/diag/rdbms/<dbname>/ <instname>/trace		 Diagnosability trace directory path
_diag_adr_trace_dest = '/u01/orabase/diag/rdbms/orabase/orabase/trace'
_DISABLE_DESTRUCTIVE_PATCH_OPERATION
Default: TRUE		 Is destructive operation allowed in a patch
_disable_destructive_patch-operation=FALSE
_INIT_SQL_FILE
Default: $ORACLE_HOME/RDBMS/ADMIN/SQL.BSQ		 File containing SQL statements to execute upon database creation
TBD
 
FLASHBACK
_ALLOCATE_FLASHBACK_BUFFER
Default: FALSE		 Allocate flashback buffer at mount time even if flashback is off
TBD
_CHECK_BLOCK_NEW_INVARIANT_FOR_FLASHBACK
Default: FALSE		 Check block new invariant for flashback
TBD
_DB_FLASHBACK_IOBUF_SIZE
Default: 1		 Flashback IO Buffer Size
TBD
_DB_FLASHBACK_LOG_MIN_SIZE
Default: 16777216		 Minimum flashback database log size in bytes
TBD
_DB_FLASHBACK_LOG_MIN_TOTAL_SPACE
Default: 0		 Minimum flashback database log total space in bytes
TBD
_DB_FLASHBACK_NUM_IOBUF
Default: 64		 Flashback Number of IO buffers
TBD
_DISABLE_FLASHBACK_ARCHIVER
Default: 0		 Disable flashback archiver
TBD
_DISABLE_FLASHBACK_RECYCLEBIN_OPT
Default: TRUE		 Don't use the Flashback Recyclebin optimization
TBD
_DISABLE_FLASHBACK_WAIT_CALLBACK
Default: FALSE		 Disable flashback wait callback
TBD
_DISABLE_KCB_FLASHBACK_BLOWNEW_OPT
Default: FALSE		 Disable KCB flashback block new optimization
TBD
_DISABLE_KCBL_FLASHBACK_BLOCKNEW_OPT
Default: FALSE		 Disable KCBL flashback block new optimization
TBD
_DROP_FLASHBACK_LOGICAL_OPERATIONS_ENQ
Default: FALSE		 Drop logical operations enqueue immediately during flashback marker generation
TBD
_ENABLE_SECUREFILE_FLASHBACK_OPT
Default: FALSE		 Enable securefile flashback optimization
TBD
_FLASHBACK_11_1_ BLOCK_NEW_OPT
Default: FALSE		 Use 11.1 flashback block new optimization scheme
TBD
_FLASHBACK_ALLOW_NOARCHIVELOG
Default: FALSE		 Allow enabling flashback on noarchivelog database
TBD
FLASHBACK_ARCHIVER_PARTITION_SIZE
Default: 0		 Flashback archiver table partition size
TBD
_FLASHBACK_BARRIER_INTERVAL
Default: 1800		 Flashback barrier interval in seconds
TBD
_FLASHBACK_COPY_LATCHES
Default: 10		 Number of flashback copy latches
TBD
_FLASHBCK_DATABASE_TEST_ONLY
Default: FALSE		 Run Flashback Database in test mode
TBD
_FLASHBACK_DELETE_CHUNK_MB
Default: 128		 Amount of flashback log (in MB) to delete in one attempt
TBD
_FLASHBACK_DYNAMIC_ENABLE
Default: TRUE		 Enable flashback enable code path
TBD
_FLASHBACKDYNAMIC_ENABLE_FAILURE
Default: 0		 Simulate failures during dynamic enable
TBD
_FLASHBACK_ENABLE_RA
Default: TRUE		 Flashback enable read ahead
TBD
_FLASHBACK_FORMAT_CHUNK_MB
Default: 4		 Chunk mega-bytes for formatting flashback logs using sync write
TBD
_FLASHBACK_FORMAT_CHUNK_MB_DWRITE
Default: 16		 Chunk mega-bytes for formatting flashback logs using delayed write
TBD
_FLASHBACK_FUZZY_BARRIER
Default: TRUE		 Use flashback fuzzy barrier
TBD
_FLASHBACK_GENERATION_BUFFER_SIZE
Default: 16777216		 Flashback generation buffer size
TBD
_FLASHBACK_HINT_BARRIER_PERCENT
Default: 20		 Flashback hint barrier percent
TBD
_FLASHBACK_LOG_IO_ERROR_BEHAVIOR
Default: 0		 Specify Flashback log I/O error behavior
TBD
_FLASHBACK_LOG_MIN_SIZE
Default: 100		 Minimum flashback log size
TBD
_FLASHBACK_LOG_RAC_BALANCE_FACTOR
Default: 10		 Flashback log RAC balance factor
TBD
_FLASHBACK_LOG_SIZE
Default: 1000		 Flashback log size
TBD
_FLASHBACK_LOGFILE_ENQUEUE_TIMEOUT
Default: 600		 Dlashback logfile enqueue timeout for opens
TBD
_FLASHBACK_MARKER_CACHE_ENABLED
Default: TRUE		 Enable flashback database marker cache
TBD
_FLASHBACK_MARKER_CACHE_SIZE
Default: 328		 Size of flashback database marker cache
TBD
_FLASHBACK_MARKER_FOR_EVERY_GRP
Default: FALSE		 Generate a new flashback marker for every GRP
TBD
_FLASHBACK_MAX_LOG_SIZE
Default: 0		 Maximum flashback log size in bytes (OS limit)
TBD
_FLASHBACK_MAX_N_LOG_PER_THREAD
Default: 2048		 Maximum number of flashback logs per flashback thread
TBD
_FLASHBACK_MAX_STANDBY_SYNC_SPAN
Default: 300		 Maximum time span between standby recovery sync for flashback
TBD
_FLASHBACK_N_LOG_PER_THREAD
Default: 128		 Desired number of flashback logs per flashback thread
TBD
_FLASHBACK_PREPARE_LOG
Default: TRUE		 Prepare Flashback logs in the background
TBD
_FLASHBACK_RECLAIM_MONITOR_WINDOW
Default: 7		 Proactive flashback logs reclamation window
TBD
_FLASHBACK_RECLAIM_SPEED_UP
Default: FALSE		 Proactive flashback logs reclamation speed up
TBD
_FLASHBACK_SIZE_BASED_ON_REDO
Default: TRUE		 Size new flashback logs based on average redo log size
TBD
_FLASHBACK_STANDBY_BARRIER_INTERVAL
Default: 1		 Flashback standby barrier interval in seconds
TBD
_FLASHBACK_STANDBY_CHECK_BARRIER_MIRA
Default: 20		 Flashback standby check barrier generation in seconds
TBD
_FLASHBACK_STANDBY_CHECK_MINPFH_MIRA
Default: 15		 Flashback standby check minimum high fuzzy scn in seconds
TBD
_FLASHBACK_STBY_SUPPORT_MIRA
Default: TRUE		 Flashback database on standby supports MIRA
TBD
_FLASHBACK_VALIDATE_CONTROLFILE
Default: FALSE		 Validate flashback pointers in controlfile for 11.2.0.2 data base
TBD
_FLASHBACK_VERBOSE_INFO
Default: FALSE		 Print verbose information about flashback database
TBD
_FLASHBACK_WRITE_MAX_LOOP_LIMIT
Default: 10		 Flashback writer loop limit before it returns
TBD
_MINIMUM_DB_FLASHBACK_RETENTION
Default: 60		 Minimum flashback retention
TBD
_PERCENT_FLASHBACK_BUF_PARTIAL_FULL
Default: 50		 Percent of flashback buffer filled to be considered partial full
TBD
_SIOP_FLASHBACK_SCANDEPTH
Default: 20		 Shared IO pool flashback io completion scan depth
TBD
_STANDBY_AUTO_FLASHBACK
Default: TRUE		 Standby automatic flashback when primary flashed back
TBD
_VALIDATE_FLASBACK_DATABASE
Default: FALSE		 Scan database to validate result of flashback database
TBD
_VERIFY_FLASHBACK_REDO
Default: TRUE		 Verify that the redo logs needed for flashback are available
TBD
 
GROUP BY
_GROUPBY_NOPUSHDOWN_CUT_RATIO
Default: 3		 Groupby nopushdown cut ratio
TBD
_GROUPBY_ORDERBY_COMBINE
Default: 5000		 Groupby/orderby don't combine threshold
TBD
_OPTIMIZER_AGGR_GROUPBY_ELIM
Default: TRUE		 Group-by and aggregation elimination
TBD
_OPTIMIZER_REDUCE_GROUPBY_KEY
Default: TRUE		 Group-by key reduction
TBD
_PX_GROUPBY_PUSHDOWN
Default: FORCE		 Perform group-by pushdown for parallel query
TBD
 
HANG MANAGER
_HANG_ROOT_HA_PHASE_TRIGGER_TIME
Default: 300		 Hang Management root HA phase trigger time
TBD
_HANG_RUNNING_IN_LRG
Default: FALSE		 Hang Management running in LRG
TBD
_HANG_SHORT_STACKS_OUTPUT_ENABLED
Default: FALSE		 If TRUE hang manager outputs short stacks
TBD
_HANG_SIGNATURE_LIST_MATCH_OUTPUT _FREQUENCY
Default: 10		 Hang Signature List matched output frequency
TBD
_HANG_SINGLETON_DETECTION_RW_ENABLED
Default: FALSE		 Hang Management singleton detection enabled for read-write
TBD
_HANG_SINGLETON_RESOLUTION_RW_ENABLED
Default: FALSE		 Hang Management singleton resolution enabled for read-write
TBD
_HANG_STATISTICS_COLLECTION_INTERVAL
Default: 15		 Hang Management statistics collection interval in seconds
TBD
_HANG_STATISTICS_COLLECTION_MA_ALPHA
Default: 30		 Hang Management statistics collection moving average alpha
TBD
_HANG_STATISTICS_HIGH_IO_PERCENTAGE_ THRESHOLD
Default: 25		 Hang Management statistics high IO percentage threshold
TBD
_HANG_TERMINATE_SESSION_REPLAY_ENABLED
Default: TRUE		 Hang Management terminates sessions allowing replay
TBD
_HANG_TRACE_INTERVAL
Default: 32		 Hang Management trace interval in seconds
TBD
_HANG_VERIFICATION_INTERVAL
Default: 46		 Hang Management verification interval in seconds
TBD
_KSV_POOL_HANG_KILL_TO
Default: 0		 Bg slave pool terminate timeout
TBD
_LM_HB_ACCEPTABLE_HANG_CONDITION
Default: DEFAULT		 List of acceptable hang conditions in heartbeat check
TBD
_LM_HB_EXPONENTIAL_HANG_TIME_FACTOR
Default: 2		 Heartbeat exponential hang time multiplier
TBD
_LMHB_MAXIMUM_HANG_REPORT_COUNT
Default: 20		 Maximum heartbeat hang report count
TBD
_LM_RCVR_HANG_ALLOW_TIME
Default: 70		 Receiver hang allow time in seconds
TBD
_LM_RCVR_HANG_CFIO_KILL
Default: FALSE		 To kill receiver hang at control file IO
TBD
_LM_RCVR_HANG_CHECK_FREQUENCY
Default: 20		 Receiver hang check frequency in seconds
TBD
_LM_RCVR_HANG_CHECK_SYSTEM_LOAD
Default: TRUE		 Examine system load when check receiver health
TBD
_LM_RCVR_HANG_KILL
Default: TRUE		 To kill receiver hang
TBD
_LM_RCVR_HANG_SYSTEMSTATE_DUMP_LEVEL
Default: 0		 Systemstate dump level upon receiver hang
TBD
_LOCAL_HANG_ANALYSIS_INTERVAL_SECS
Default: 3		 The interval at which local hang analysis is run
TBD

Related Topics
DBMS_WORKLOAD_REPOSITORY
INIT.ORA & SPFILE
Synonyms
Underscore Parameters: Page 1 of 5
Underscore Parameters: Page 3 of 5
Underscore Parameters: Page 4 of 5
Underscore Parameters: Page 5 of 5
What's New In 19c
What's New In 20c-21c