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Thursday, December 17, 2020

Oracle Database 21c Initialization Parameter, Hidden Parameter introduced, deprecated and obsolete.

Objective:

The objective of this blog is to share the information about the new database parameter and hidden parameter introduced in 21c along with the deprecated and obsolete database parameter.

The parameters are the backbone of the database that is responsible for running the database with full utilized I/O operations. The database parameters can be modified in the system or session level. Some of the parameters can be altered in memory level and do not require any database restart, and some are not which requires a database to restart to get reflect for the database instance. 

Oracle Database Parameters are the predefined values set for various memory segments and information on different location of files and log files for bringing up the database instance. Deprecated parameter means the parameter that is being replaced by a better alternative and shouldn’t be used, and obsolete parameter means the parameters are removed from the database and no longer in use. 

The Oracle Database Hidden parameter must not be changed without taking concern from Oracle support, changing the hidden parameter value may result in higher performance degradation and also serious corruption issue. Please go through the Metalink Doc ID 315631.1 for more information.

Note: The database parameter mentioned here are compared with respect to the previous production release database version 19c.

Now let’s begin to have the information on Oracle Database Version 21c parameters.

 

New Parameter introduced in Version 21c in comparison to 19c .

NAME

ISDEP

DESCRIPTION

_gc_policy_time

FALSE

how often to make object policy decisions in minutes

_gc_undo_affinity

FALSE

if TRUE, enable undo affinity

allow_deprecated_rpcs

FALSE

allow deprecated rpcs

auto_start_pdb_services

FALSE

Automatically start all PDB services on PDB Open

blockchain_table_max_no_drop

FALSE

maximum idle retention minutes for blockchain tables

container_data

FALSE

which containers should data be returned from?

dbnest_enable

FALSE

database Nest enable

dbnest_pdb_fs_conf

FALSE

PDB Filesystem configuration

diagnostics_control

FALSE

controls response when 'enabling diagnostics' privilege is absent

drcp_connection_limit

FALSE

DRCP connection limit

drcp_dedicated_opt

FALSE

Turn on/off dedicated optimization for DRCP

enable_per_pdb_drcp

FALSE

Turn on/off per PDB DRCP

heartbeat_batch_size

FALSE

Number of heartbeats to be sent in a batch

ignore_session_set_param_errors

FALSE

Ignore errors during alter session param set

inmemory_deep_vectorization

FALSE

In-Memory Deep Vectorization Enabled

kafka_config_file

FALSE

KSR pub/sub external message bus(KSRPS) CONFIGuration file

mandatory_user_profile

FALSE

Enforce Mandatory Password Profile for multitenant database

max_auth_servers

FALSE

Maximum size of auth pool

min_auth_servers

FALSE

Minimum size of auth pool

native_blockchain_features

FALSE

Native block chain enable/disable

optimizer_capture_sql_quarantine

FALSE

enable automatic creation/update of sql quarantine configuration

optimizer_cross_shard_resiliency

FALSE

enables resilient execution of cross shard queries

optimizer_real_time_statistics

FALSE

optimizer real time statistics on conventional DML

optimizer_session_type

FALSE

Controls Auto Index

optimizer_use_sql_quarantine

FALSE

enable use of sql quarantine

pkcs11_library_location

FALSE

PKCS#11 library location for Transparent Data Encryption

pmem_filestore

FALSE

Persistent Memory Filestore list

resource_manager_cpu_scope

FALSE

scope of CPU resource management

result_cache_execution_threshold

FALSE

minimum executions before a PL/SQL function is cached

result_cache_max_temp_result

FALSE

maximum temp per result as percent of total temp for result cache

result_cache_max_temp_size

FALSE

maximum amount of temp space to be used

shard_queries_restricted_by_key

FALSE

add shard key predicates to the query

tablespace_encryption_default_algorithm

FALSE

default tablespace encryption block cipher mode

tde_key_cache

FALSE

Enable caching of TDE intermediate key

timezone_version_upgrade_online

FALSE

enable/disable time zone version upgrade online

 

New Hidden parameter introduced in Version 21c in comparison to 19c.

PARAMETER

PARAMETER_DESCRIPTION

_STFForceTranslateOracleSQL

if TRUE translation profile will translate Oracle SQL statements

__db_pmem_direct_map_size_metadata

Size of PMEM memory metadata of DEFAULT buffer pool for standard block size buffers

__sess_template_test_attrs

session template: include test attributes

_adaptive_scalable_log_writer_evaluation_fraction

Serial/parallel log writer evaluation fraction (in 10000ths)

_adaptive_scalable_log_writer_evaluation_interval

Serial/parallel log writer evaluation interval (in seconds)

_age_block_batch_timeout_ms

timeout before shipping out the batched age blockmessages in milliseconds

_alert_segment_size

Alert-log segment size in MBs (1024*1024)

_alert_segment_textfile

Alert-log text-file also to be segmented

_alert_segments_max

Alert-log max segments to retain, 0 for unlimited

_allow_cross_version_chunk_move

Oracle internal parameter

_allow_fallback_to_dbkey

if TRUE, allow fallback to dbkey

_allow_privileged_session_dblink_conn

Allow privileged session for dblink connection

_allow_triggers_on_vpd_table

Allow triggers on VPD protected table in DML

_allow_xdb_anonymous_logon

Allow XDB anonymous logon

_allowed_pvf_owners

List of schemas allowed to own password verification function

_aq_queue_global_service

AQ queue global service

_aq_tm_processes_dump_interval

Time(minutes) between consecutive Dumps in alert log

_aqsharded_cached_hint

sharded queue cached hint

_aqsharded_enq_fresh_ptn_reload

start enqueueing to a fresh partition on reload

_aqsharded_lowmem_timeout

sharded queue low mem timeout (in centiseconds)

_aqsharded_reload_tune

sharded queue tune reload behaviour

_asm_allow_appliance_offlineonline

Allow OFFLINE/ONLINE DISK/FAILUREGROUP on ASM Appliances

_asm_buffer_overlap_tracer

Enables kfioBufOverlapTracer

_asm_diskgroup_renew_timeout

timeout FENC will give former ASMB group owner to renew

_asm_dump_split_pw

Seconds to wait before requesting dump of split pending writes

_asm_enable_map_share

Enable ASM extent map share

_asm_enable_vfreloc_on_rm

Enable voting file relocation on rolling migration

_asm_frag_threshold

Percentage threshold before disk/diskgroup is deemed fragmented

_asm_hard_check

H.A.R.D. check buffer before write operation

_asm_iosfailover_freq

Frequency limit after which db gives up on failing over to IOS

_asm_iosfailover_timeout

Time window within which db tries to failover to IOS

_asm_max_kfsg_free_heap_perc

Max percentage of SGA memory reserved for kfsga free heap

_asm_max_kfsg_free_heap_size

Max buffer size reserved for kfsga free heap

_asm_max_occupied

Maximum percentage of disk occupied to check for fragmentation

_asm_min_occupied

Minimum percentage of disk occupied to check for fragmentation

_asm_node_number

ASM node number

_asm_offline_wait_timeout

Timeout for offline wait

_asm_ownerid_trace_timeout

ownerid tracing threshold in seconds

_asm_pst_rsinfo

file redundancies to consider during PST liveness checks

_asm_scrub_max_cod_wait

Number of minutes to delay scrub COD recovery

_asm_shared_pool_latch_timeout

seconds before terminating inst if ASMB is waiting for shared pool latch during shutdown

_asm_showpdb_asmtbl

Allow asm table values to be shown in pdb

_asm_write_cancel_timeout_percentage

Percentage of the write timeout to wait before optional offline

_asm_xrov_cachelgio

ADVM cache large IO

_assert_single_current_buffer

if TRUE, check and assert only one current buffer

_assm_auto_tracing_threshold

ASSM threshold to start space search tracing

_auto_mv_enabled

enable/disable Auto MV logic in the sql access advisor

_autoptn_costing

DBMS_AUTO_PARTITION is compiling query for cost estimates

_autoptn_flags

DBMS_AUTO_PARTITION flags

_autoptn_translate_table_name

DBMS_AUTO_PARTITION table name translation

_autoptn_workload_id

DBMS_AUTO_PARTITION workload id

_autosts_capture_control

internal controls for auto STS capture

_autosts_long_interval

Auto STS long flush interval

_autosts_retention_interval

Auto STS retention interval

_autosts_short_interval

Auto STS short flush interval

_aux_storage_size

Auxillary storage for PDB.

_awr_data_masking

Enable/Disable AWR data masking functionality

_backup_interrupt_wait_time

specifies interrupt wait time in centi seconds

_bct_public_dba_buffer_dynresize_delay

control frequency of dynamic resizing of public dba buffers

_bigdata_offload_flag

BigDataSQL offload flag

_block_change_tracking_file

file location for broker to reenable BCT

_blockchainHeapSize

Set the heap size in bytes for blockchain

_blockchainTracing

Set tracing for blockchain

_blockchain_forced_off

force off blockchain

_blockchain_txn_apis_enabled

If true, the txn layer blockchain API'S kick in

_blockchain_txn_test_lvl

blockchain txn test lvl

_boc_mode

Broadcast-on-commit mode

_boc_rdma_wait_time

BOC RDMA busy wait time (microseconds)

_buffer_requests_to_drain

Buffer for requests to drain before planned failover

_bypass_sensitive_context

bypass sensitive handling for specific SYS_CONTEXT() parameters

_cdb_init_batch_size

Batch size for reading pdb info during CDB mount

_cdb_svlt_use_tcps

Use TCPS for CDB Servlet

_cell_metadata_compression

Cell metadata compression strategy

_cell_offload_vector_groupby_external

enable cell offload of vector group by with external tables

_cgs_clscevents_dumpinterval

cgs clsce events statistics dump interval in seconds

_cgs_publish_netinfo_collect_event_chmjf

enable cgs publish collect_netinfo event to event stream for CHM with CHM'S JASON format

_cgs_publish_netinfo_collect_event_chmjf_batchsz

batch size of cgs events publishing to CHM in json format via clsce event stream

_cgs_query_net_interface

api to query network interface

_cloud_mandatory_profile_setup

Mandatory Profile Setup for Multitenant Cloud Environment

_cluster_database_instances

number of instances to use for sizing cluster db SGA structures

_connect_string_settings_after_logon_triggers

set connect string session settings after logon triggers

_connect_string_settings_unalterable

make connect string session settings unalterable

_connstr_test_param

connect string workload behavior spare param

_consensus_follower_election_timeout

consensus follower's election timeout

_consensus_leader_heartbeat_interval

consensus leader's heartbeat interval

_consensus_leader_maximum_heartbeats

consensus leader's maximum heartbeats

_consensus_queue_maximum_elements

consensus queue maximum elements

_consensus_slaves_maximum_count

consensus slaves maximum count

_cp_del_free_sess

connection pool: delete free sessions when at PDB limit

_cp_del_free_sess_limit_secs

connection pool: delete free sessions time limit (in seconds)

_cputime_limit_parallel_fptr

CPU-time limit for for parallel first-pass recovery

_create_pdb_disable_mirror_reads

Disable mirror reads during create pdb

_create_pdb_flashback_barrier

force flashback barrier for create pdb

_cross_con_remove_pushed_preds

remove pushed predicates from query fetching across containers

_ctas_numfrags_hint

Hint for number of partition fragments to be loaded in a CTAS

_ctex_fk_copy_mode

Create table for exchange Copy mode for referential constraints

_datapump_bypass_tstz_check

Bypass Data Pump TSTZ version checking during import.

_datapump_hide_cdb_warning

Hide Data Pump warning for CDB$ROOT and PDB$SEED

_db_cache_advice_size_submultiple

cache advisory size submultiple

_db_cache_pmem_confidence_try

DB Cache PMEM buffer promote attempts for greater confidence

_db_cache_pmem_promotion_touch_rate_reset_interval

DB Cache PMEM promotion touch rate reset interval in sec

_db_cache_pmem_promotion_touch_rate_threshold_time

DB Cache PMEM promotion touch rate threshold time in sec

_db_cache_pmem_touch_rate_compare_per

DB Cache PMEM buffer touch rate additive percentage when comparingagainst dram touch rate

_db_cache_pmemp_len

DB Cache PMEM promotion list max length

_db_cache_xmem_promotion_algo_chosen

DB Cache Xmem/Pmem promotion algo

_db_nvm_promotion_deferred_tchcnt

touch count threshold which allows deferred background based nvm buffer promotion

_db_pmem_auto_resize_interval

PMEM auto resize interval in minutes

_db_pmem_direct_map_size

Size of direct mappable PMEM buffer cache

_db_replay_security_config

Database Replay Security Configuration

_dbnest_resource_opts

dbNest - resource options

_dbnest_skip_fed_root

Fed root is skipped so CDB nest is root of all pdbs

_dbopen_breakpoint

ALTER DATABASE OPEN codepath breakpoint

_dbreplay_mpk_key

Database Replay Package Key

_ddlapply_enable

DDL VIA APPLY Enable

_default_ini_trans_index

Default value of INI_TRANS enforced by DWCS lockdown for indexes

_default_ini_trans_table

Default value of INI_TRANS enforced by DWCS lockdown for tables

_default_oracle_fs_type

default file system type for an oracle file system

_default_service

Run default service

_defer_rcv_pdb_attach

Defer PDB domain attach in instance recovery

_defer_rewrap_controlfile_key_history

if TRUE, defer rewrap control file TS keys under next PDB open

_dgb_dgpdb_appst

DGPDBs with apply state off

_dgpdb_file_name_convert

datafile name convert patterns and strings for per PDB standby

_dgpdb_standby_controlfile_name

a name template with three %u's for DGPDB standby controlfile

_direct_io_via_mapped_pmem

if TRUE, direct path I/O will attempt to memory map files on PMEM

_disable_block_corruption_track

disable block corruption tracking

_disable_foreign_scn_adjust

Disable foreign SCN adjustment

_disable_ilm_internal

Force disable internal ilm stats and drop ilm segment

_disable_mandatory_profile_onclone

Disable Mandatory Profile check on clone of a PDB

_disable_marking_noops

Don't mark any captured statements as no-ops.

_disable_orphan_pdb_recovery

Disable PDB PITR/FB to orphan PDB incarnation

_disable_pdb_space_check

Disable pdb storage usage check in the session

_disable_sga_filedel

disable deletion of files used for SGA

_dmm_ser_test

Stress testing for serialized models

_dmm_xgboost_max_memory

xgboost maximum memory

_dp_force_length_semantics

Force nls length semantics

_dynamic_hash_bucket_array

dynamic hash bucket array

_dynamic_processes_force_timeout

dynamic process force timeout

_dynamic_processes_max_oom_timeout

dynamic process max timeout for out of memory

_dynamic_processes_wait_timeout

dynamic process wait timeout for new process

_eighteenth_spare_pdb_parameter

eighteenth spare pdb parameter - integer

_eighth_spare_pdb_parameter

eighth spare pdb parameter - integer

_eighty-second_spare_parameter

eighty-second spare parameter - string

_eleventh_spare_pdb_parameter

eleventh spare pdb parameter - integer

_enable_bug_29838374

enable/disable bug fix 29838374

_enable_cdb_all_sync

Is CDB-wide ALL sync enabled

_enable_dbwr_parallel_invalidations

if TRUE, enables flush and invalidate by DBWRs

_enable_dynamic_processes

dynamic process SOs

_enable_fsdirect_odmlib

enable or disable FsDirect static ODM library

_enable_fsdirect_pin

enable direct pin of FsDirect blocks

_enable_fsdirect_rac

enable FsDirect in RAC

_enable_gsm_listener_networks

gsm listener in listener networks

_enable_ignorable_error_capture

Capture statement if error is ignorable

_enable_increase_lms_process

set to true to allow _increase_lms_process changes

_enable_load_from_clone

Is load from a Root Clone allowed

_enable_log_memory_protection_key

enable memory protection keys (log)

_enable_memory_protection_keys

Enable memory protection keys usage

_enable_mle

enable MLE

_enable_pdb_skiplist_recovery

Enable pdb skip list setup during media recovery.

_enable_pdb_skiplist_redogen

Enable pdb skip list setup during redo generation.

_enable_per_container_acl

Enable Per Container ACL

_enable_pmem_direct_cache

if TRUE, enable PMEM direct mapped buffers

_enable_pmem_exchange

if TRUE, enable PMEM exchange during promotion

_enable_pmem_prefetch

if TRUE, enable prefecting from PMEM

_enable_ptime_update_for_sys

Enable/Disable update of user$ for sys

_enable_tenant_id_check

Enable Tenant Id check for database link

_enable_tenant_id_transfer

Enable Tenant Id transfer

_enable_unified_memory

Enable use of unified PGA pool

_endprot_stack_segments

overrun protection for kgh stack segments

_enforce_minimum_password_rollover_time

Enforce minimum PASSWORD_ROLLOVER_TIME of one hour

_enqueue_wall_clock_time

if TRUE, use KSUFTIME timer

_exa_pmemlog_threshold_usec

maximum i/o time (usecs) for enabled Exadata PMEMLog

_failover_svrcsum

enable server checksum to optimize failover

_fb_log_max_rereads

Maximum number of rereads after reading a corrupt flashback block

_fb_recovery_slave_count

Number of recovery slaves to be used by the FLASHBACK DATABASE

_fbda_adv_gbl_bscn_bcast_interval

flashback archiver broadcast interval to advance global barrier SCN

_ffs_in range_scan_threshold

threshold of min percentage of block read to use ffs in rs

_fifteenth_spare_pdb_parameter

fifteenth spare pdb parameter - integer

_fifth_spare_pdb_parameter

fifth spare pdb parameter - integer

_fiftieth_spare_pdb_parameter

fiftieth spare pdb parameter - string list

_fifty-eighth_spare_pdb_parameter

fifty-eighth spare pdb parameter - boolean

_fifty-fifth_spare_pdb_parameter

fifty-fifth spare pdb parameter - boolean

_fifty-first_spare_pdb_parameter

fifty-first spare pdb parameter - boolean

_fifty-fourth_spare_pdb_parameter

fifty-fourth spare pdb parameter - boolean

_fifty-ninth_spare_pdb_parameter

fifty-ninth spare pdb parameter - boolean

_fifty-second_spare_pdb_parameter

fifty-second spare pdb parameter - boolean

_fifty-seventh_spare_pdb_parameter

fifty-seventh spare pdb parameter - boolean

_fifty-sixth_spare_pdb_parameter

fifty-sixth spare pdb parameter - boolean

_fifty-third_spare_pdb_parameter

fifty-third spare pdb parameter - boolean

_first_spare_pdb_parameter

first spare pdb parameter - integer

_fixup_all_apps

Callback to fix up replay state of all applications

_fixup_app_pdb_status_in_root

application name whose PDB application status should be fixed up

_fixup_cdb_apps

Callback to fix up replay state of CDB-wide applications

_force_dax_io_err

Force I/O error on online/standby redo log

_force_pmem_direct_mapped_cache_scan

if TRUE, force PMEM mapped direct path scan to cache path scan

_fortieth_spare_pdb_parameter

fortieth spare pdb parameter - string

_forty-eighth_spare_pdb_parameter

forty-eighth spare pdb parameter - string list

_forty-fifth_spare_pdb_parameter

forty-fifth spare pdb parameter - string list

_forty-first_spare_pdb_parameter

forty-first spare pdb parameter - string list

_forty-fourth_spare_pdb_parameter

forty-fourth spare pdb parameter - string list

_forty-ninth_spare_pdb_parameter

forty-ninth spare pdb parameter - string list

_forty-second_spare_pdb_parameter

forty-second spare pdb parameter - string list

_forty-seventh_spare_pdb_parameter

forty-seventh spare pdb parameter - string list

_forty-sixth_spare_pdb_parameter

forty-sixth spare pdb parameter - string list

_forty-third_spare_pdb_parameter

forty-third spare pdb parameter - string list

_fourteenth_spare_pdb_parameter

fourteenth spare pdb parameter - integer

_fourth_spare_pdb_parameter

fourth spare pdb parameter - integer

_fsdirect_fast_file_create

Allow optimized file creation path for FsDirects

_gc_disable_cell_populate

if TRUE, disable cell ram cache populate

_gc_down_convert_after_write

if TRUE, down-convert lock after a write

_gc_fast_index_split_timeout

fast index split wait timeout

_gc_rdma_connections

maximum number of buffer cache RDMA connections

_gc_undo_header_rdma_read

if TRUE, rdma read of undo headers is enabled

_gcr_disabled_actions

gcr disabled actions list

_gcr_disabled_metrics

gcr disabled metrics list

_gcr_enable_async_slaves

if TRUE, GCR will spawn slave actions asynchronously

_gcr_enable_ktfbue_gather_stats

enable/disable gather stats on X$KTFBUE

_gcr_enable_pdb_abort

if TRUE, GCR will process pdb abort messages

_gcr_ges_cachedres_mult

ges cached resources multiplier

_gcr_ges_longchain_mult

ges longchain multiplier

_gcr_high_cpwt_threshold

longest tolerable ctwr process waits time

_gcr_high_fbwt_threshold

longest tolerable free buffer waits time

_gcr_high_hashlist_latch_nowait_misses

highest hash list get nowait fails tolerable

_gcr_high_hashlist_latch_wait_misses

highest hash list get wait fails tolerable

_gcr_high_lfsci_threshold

longest tolerable log file switch (checkpoint incomplete) wait

_gcs_current_rdma

if greater than 0, rdma read of current blocks is enabled

_gcs_current_rdma_grant_global

if TRUE, enable rdma read of current blocks for global role

_gcs_dynamic_sga_preference

gcs dynamic sga preference

_gcs_spin_check_threshold

spin check attempt count

_gcs_spin_check_time_interval

spin check time interval in seconds

_gcs_verify_antilock

if TRUE, enable anti-lock check

_ges_optimizations

GES optimizations level

_gsm_srvctl_diag_time

gsm invoked srvctl pre-timeout diagnostic time

_gsm_srvctl_timeout

gsm invoked srvctl timeout

_gwm_disable_ra

Oracle internal parameter

_gwm_lagtype

gsm lag type

_gwm_spare1

gsm spare 1

_gwm_sys_ddl

allow DDL as SYS

_gwm_use_srvctl

use srvctl for service mnagement

_gws_catalog_wallet

the sharding catalog has a wallet

_gws_encddl

Encrypt DDL text.

_hang_analyze_elapsed_time_limit

Hang Analyze elapsed time limit in seconds

_hang_bool_spare3

Hang Management bool 3

_hang_cpu_hung_thresh_sec

Hang Manager threshold for resmgr:cpu quantum

_hang_fast_tracked_hang_verification_interval

Hang Manager fast-track hang verification interval

_hang_high_session_count_update_hb_threshold

Hang Manager high session count update heartbeat threshold

_hang_int_spare3

Hang Management int 3

_hang_low_wait_time_cutoff

Hang Management low wait time cutoff in seconds

_hang_mark_some_idle_waits_terminal

Hang Management mark some wait events as terminal waits

_hang_max_local_db_clients_allowed

Hang Manager maximum local db clients allowed

_hang_px_resolution_on_asm_enabled

Hang Management px resolution on ASM enabled

_hang_resolution_partial_hangs_on_asm_enabled

Hang Management resolution of partial hangs on ASM enabled

_hang_sess_enq_wait_blocked_session_threshold

Hang Management session enqueue wait blocked session threshold

_hang_sess_enq_wait_resltn_trig_time

Hang Management session enqueue wait resolution trigger time

_hcs_disable_all_qry_optz

skip all query optimization on generated SQL

_hcs_disable_audit_opt

disable audit optimization

_hcs_disable_av_sql_hint

disable analytic view sql hint

_hcs_disable_calc_union_opt

disable calc union optimization

_hcs_disable_dt_opt_cell_qry

disable cell query optimizations for datatype queries

_hcs_disable_inline

add inline hint to star block

_hcs_disable_merge_fltr_star_opt

disable merge filter star optimization

_hcs_disable_no_bdfltrd_opt

apply no base data filtered optimization

_hcs_disable_prune_unslvd_star_opt

disable prune unsolved star optimization

_hcs_disable_smooth_noop_descendants

perform smooth no-op descendants

_hcs_disable_sql_plan_baselines

disable sql plan baselines

_hcs_disable_use_cache_star_opt

disable use cache star optimization

_hcs_disable_xform_gby

disable transform group by

_hcs_enable_adw

enable ADW

_hcs_enable_av_auto_cache

enable AV auto-cache

_hcs_enable_basetbl_transform

enable base table transform

_hcs_enable_code_trc

enable code tracing

_hcs_enable_cube_join

enable cube join

_hcs_enable_fact_rows

enable fact rows

_hcs_log_max_segments

maximum number of HCS log segments, 0 for unlimited

_hcs_log_segment_size

HCS log segment size in MB

_hcs_max_mdx_cursors

maximum number of MDX cursors

_hcs_mdx_sim_sga_alloc_err

simulate mdx sga allocation error

_hcs_mdx_sim_so_fail

simulate state object failure

_hcs_mdx_sleep_loc

mdx location to sleep for testing

_hcs_sim_sqlopt_err

simulate sql optimization error

_hstpr_prediction_interval

resource SO prediction interval

_hstpr_use_linear_prediction

use session SO lin-reg prediction

_hstpr_use_periodic_prediction

use session SO periodic prediction

_http_port

HTTP port number registered with local listener

_idle_session_scan_frequency

Idle session scan frequency (in seconds)

_ignore_pdb_listener

ignore pdb listener

_ignore_svc_name_conv_mismatch

Suppress ORA-65174 for service_name_convert clause mismatch

_imado_enable_coloptim

Enable AIM Column level optimizations

_imado_enhancements

AIM enhancements

_imr1_slave

IMR1 slave

_imr_slave_debug

IMR slave debug flags

_imtxnrma_table_flags

In-Memory RMA Txn Table cache Flags

_increase_lmd_process

modifying this hidden parameter, will modify the numberof lmd process by the valueof this parameter

_inmemory_dynamic_scans_result_buffers

No. of LWT allocated result buffers per thread

_inmemory_hpk4sql_debug

In-Memory HPK4SQL debug

_inmemory_hpk4sql_filter_threshold

In-Memory HPK4SQL filter threshold

_inmemory_hpk4sql_flags

In-Memory HPK4SQL flags

_inmemory_hpk4sql_kv_seg_size

In-Memory HPK4SQL kv segment size

_inmemory_hpk4sql_partbuf_maxrow

In-Memory HPK4SQL partbuf maxrow

_inmemory_hpk4sql_partbuf_minrow

In-Memory HPK4SQL partbuf minrow

_inmemory_hwm_expansion_rac

If 0, the highwatermark CU is dropped when expanded

_inmemory_hwm_inv_blocks_threshold

If 0, expansion will occur even for very small hwm imcu

_inmemory_hybrid_selectivity_threshold

Selectivity threshold for a qualifying query to enable hybrid IM scans

_inmemory_opaque_contig_space_percent

Contiguous memory for opaque VC as a percent of hard maximum

_inmemory_populate_blocks_threshold

If 0, scan triggers populate for any missing blocks

_inmemory_trickle_populate

Enable inmemory trickle populate

_instant_file_create_exascale

enable instant file creation on Exascale

_ipc_emu_aop_timeout

static emu AOP tinmeout

_ka_lma_msg_wait_count

KA maximum number of requests to retrieve per OSD wait by LMA

_ka_lma_wait_time

KA wait time for skjcxWait call by LMA process in microseconds

_kcb_reused_max

reused array max parameter

_kcrfwrma_flags

KCRFWRMA Flags

_kdlf_fast_move_compressed_lob

kdlf fast move commpressed lobs

_kdlf_layers_cache

enable kdlf securefiles layers cache

_kdli_adaptive_cache_inode

enable adaptive inode cache

_kdli_cache_inode_off_limit

cache_off limit for adaptive inode cache

_kdlwp_memory_check

bug 31354021: memory diagnostics

_kdmado_partial_pop_backoff_mb

AIM Backoff for partial populate

_kebm_preshut_act_enabled

Enable/disable MMON Pre-shutdown Action

_keep_relocated_source_pdb

Move source pdb to unplugged state after relocation

_kffmof_fprate

acceptable false positive rate [1-10000] of the kffmof bloom filter

_kffmof_size

number of entries of the kffmof opened files bloom filter

_kffmop_list_check

enable PGA mop list sanity check

_kgl_bucket_bitvector

Enable creation of PDB bit vector in KGL Hash Buckets

_kgl_bucket_bitvector_clear

Enable clearing library cache bucket bit vector

_kjac_direct_path_enabled

If direct path is enabled for TG

_kkpap_zm_pruning_cache

cache result of recursive zonemap partition pruning query

_kkpox_prtmv_rel_lock

explicitly release PRTMV heap during cursor compile

_kks_always_check_bind_equivalence

Check bind equivalence every time

_kqr_hot_copy_sample_size

number of mutex gets between periodic checks for hot objects

_kqr_hot_copy_sleep_limit

threshold of mutex sleeps to enable object hot copies

_kqr_max_hot_copies

upper limit of object hot copies allowed

_kse_snap_ring_record_min

minimize recorded information in error stack history

_ksfdx_tests

ksfdx testing - INTERNAL USE ONLY!

_ksfqp_row_count

row count of x$ksfqp

_ksipc_ipclw_rcvbuf_mb

Configure IPCLW RCVBUF SIZE (in MB)

_ksmsq_conn_per_epoch

KSMSQ Connections Per Epoch

_kspmx_enabled

KSPMX Is Enabled

_kspmxs_flush_cache_size

KSPMXS flush cache size

_kspmxs_latch_freelists

Number of managed PMEM latch freelists

_kspmxs_latch_usid_map_size

KSPMXS latch usid map size

_kspmxs_max_regions

KSPMXS max regions

_kspmxs_max_waits

KSPMXS max waits

_kspmxs_txn_freelists

Number of PMEM transactions freelists

_kspmxs_upgrade_mutexes

KSPMXS upgrade mutex

_kspmxs_usid_map_size

KSPMXS usid map size

_kspmxs_wait_buckets

KSPMXS wait buckets

_ksr_control_dyn_flags

KSR dyanamic control flags

_ksr_control_flags

KSR control flags

_ksu_proc_percent_target

dynamic process usage target

_ksu_proc_percent_threshold

dynamic process usage threshold

_ksws_alb_block_service

enable ALB Blocking of overloaded service

_ksws_alb_session_age

KSWS ALB Minimum age(seconds) of session to consider marking

_ksws_alb_test_delta_override

KSWS ALB total  sessions after which service is blocked

_ksws_alb_test_drain_timeout

KSWS ALB time in seconds before draining kicks in

_ksws_alb_test_load_balance_frequency

KSWS ALB Load Balance Frequency in deci seconds

_ksws_alb_test_load_percent

KSWS ALB Load Percentage to trigger  marking for draining

_ksws_alb_test_selection_bias

KSWS ALB percentage of sessions to target

_ksws_enable_alb

enable ALB metrics processing

_ksws_fallback_to_root

KSWS Fallback to Root CDB service

_ksws_modsvc_call_out_enabled

modify service call out enabled

_ksws_rlb_cpu_busy_scope

KSWS RLB CPU BUSY SCOPE

_ksws_use_placement_template_attribute

use placement_template attribute

_kswsas_pdb_auto_close_timeout

Close a PDB after the timeout

_ksxp_poll_netintr_timeout

ksxp poll network interrupt timeout in seconds

_ksz_dummy_parameter

Internal spare parameter for ksz.c

_ksz_dummy_parameter2

Internal spare parameter2 for ksz.c

_ktte_ts_shrink_group

tablespace shrink group

_ktte_ts_shrink_interval

tablespace shrink interval

_ldap_use_all_direct_groups_only

LDAP use all direct groups only

_ldap_warning_on_multi_shared_mappings

LDAP warning on multiple shared mappings

_link_ts_force_online

force linked tablespace to be online

_listener_registration_retry_secs

listener registration retry time (in seconds)

_lm_async_da

enable async da requests

_lm_comm_send_proxy_nr_delay

Send proxy delay before sending NULLREQ

_lm_comm_send_proxy_tkt_return

Allow send proxy to return tickets

_lm_comm_slow_op_spx_loop_threshold

GES comm slow spx operation loop threshold in microsec

_lm_comm_tkts_adpt_rsv

Adpative ticketing reserve multiple

_lm_da_win_enable

enable da windowing

_lm_da_window

number of windows in domain action

_lm_da_window_interval

Interval in centiseconds between each domain action window

_lm_default_failure_action

default failure action

_lm_enable_pdb_abort

enable pdb abort as default failure action

_lm_gcs_rht_alloc_size

gcs rht allocation chunk size

_lm_ges_rht_alloc_size

ges rht allocation chunk size

_lm_ges_rht_mem_pct

options to size RHT structures per pdb

_lm_hb_lgio_timeout

LGWR io timeout in seconds

_lm_mp_additional_big_buffers

GES MP extra big buffers per pool

_lm_mp_additional_reg_buffers

GES MP extra regular buffers per pool

_lm_mp_expand_big_pool_percent

GES MP expand big pool

_lm_mp_expand_reg_pool_percent

GES MP expand regular pool

_lm_mp_share_lms_pools

GES MP share LMS pools with critical BGs

_lm_mp_small_lms_pools

GES MP small regular pool for LMS when not sharing

_lm_new_esm

use new enter server mode code

_lm_pdb_weight_opts

options to size RHT structures per pdb

_lm_receiver_type

receiver thread type performing receive function

_lm_recovery_pdbw_reduction

recovery member pdbw reduction

_lm_resource_recycle_cnt

GES: number of resources to recycle optimization

_lm_sp_slave_mode

sendproxy slave operation mode

_lm_wrkr_mode

LMS worker thread mode

_lm_wrkr_slaves

number of LMS worker slaves

_lmhb_max_dynamic_hb

max number of proc heartbeats that can be dynamically monitored

_log_switch_tracing_iterations

no. of iterations to trace after logswitch timeout

_log_switch_tracing_timeout

dbwr to trace after logswitch timeout in secs

_max_dynamic_processes

max dynamic processes count

_max_flashback_shrink_size

maximum size(in KBs) a datafile can be shrunk with flashback DB

_max_gg_extracts

maximum limit for goldengate extract instances

_mdapi_transform_engine

DDL transformation engine

_mle_compilation_errors_are_fatal

failed compilations are fatal for MLE

_mle_compile_immediately

force compilation for MLE

_mle_enable_compilation

enable runtime compilation for MLE

_mv_logical_partition_rewrite_enabled

enable/disable Logical Partition based rewrite

_mv_logical_partition_tracking_enabled

enable/disable Logical Partition Tracking

_mv_master_lock_timeout

timeout that mv create/drop waits to lock the master table

_ndb_enable

Native Database Blockchain Enable

_nineteenth_spare_pdb_parameter

nineteenth spare pdb parameter - integer

_ninth_spare_pdb_parameter

ninth spare pdb parameter - integer

_non_blocking_hard_parse_min_extend_time

minimum additional lifetime added to cursor

_number_ksim_group_req_threshold

ksim maximum number of group operations requests

_numgrans_per_file

Number of granules per SGA file

_nusa_data_containers

list of data containers in the nusa universe

_nusa_metadata_store

metadata store in nusa

_nvmeof_zcopy_enable

Enable Zero Copy for NVMeoF

_object_activity_control

controls tracing for object activity tracking system (OATS)

_object_activity_disable

disables some object activity tracking (OATS)

_object_activity_tracking

enable object activity tracking system (OATS)

_obsolete_result_cache_mode

USERS SHOULD NOT SET THIS! Used for old qksced parameterof result_cache_mode

_ofs_read_buffer_size

OFS read ahead buffer size in bytes

_one-hundred-and-forty-first_spare_parameter

one-hundred-and-forty-first spare parameter - boolean

_one-hundred-and-forty-second_spare_parameter

one-hundred-and-forty-second spare parameter - boolean

_one-hundred-and-forty-third_spare_parameter

one-hundred-and-forty-third spare parameter - boolean

_onl_ddl_progress

track progress of online ddl

_onl_pmo_wait_query

online pmos wait for queries after swapping partitions

_onl_pmo_wait_timeout

online pmos wait for queries after swapping partitions timeout

_online_pmo_global_index_method

Unique global index method for partition maintenance DDLs

_optimize_dvconfig_cloudpdb

Optimize Database Vault setup for cloud PDB

_optimizer_exists_to_any_rewrite

consider exists-to-any rewrite of subqueries

_optimizer_nested_loop_join

favor/unfavor nested loop join

_optimizer_unnest_update_set_subq

enables unnesting of subquery in set for update

_optimizer_use_stats_models

use optimizer statistics extrapolation models

_optimizer_wc_filter_pushdown

enable/disable with clause filter predicate pushdown

_oracle_script_counter

Helper parameter to set the value of _oracle_script counter

_partial_log_preserve_space

use only required space for partial archive logs

_path_prefix_create_dir

Create path in file system for CREATE DIRECTORY with PATH_PREFIX

_pdb_char_set_intconv

Enforce internal_convert for PDB character set conversion

_pdb_clone_preserve_guid

Use same guid for a pdb clone

_pdb_create_use_sysoper_conn

spread file copy slaves across instances

_pdb_datapatch_violation_restricted

Open pdb in restricted mode for datapatch error violation

_pdb_file_copy_affinitize

spread file copy slaves across instances

_pdb_file_copy_buffers

number of buffers to use for pdb file copy

_pdb_hybrid_read_only

Hybrid read only mode allows CDB common user to patch the PDB

_pdb_ktg_buffer_size

KTG buffer size (in KB) to store inmemory traces

_pdb_oper_trace_threshold

PDB operations timing trace threshold

_pdb_oper_trace_threshold_softassert

PDB operations timing threshold soft assert

_pdb_read_only_refresh

allow refresh when pdb is open r/o

_pdb_refresh_use_dblink_to_catalog

Use central catalog for pdb refresh

_pdb_refresh_use_local_logs

Use local logs for pdb refresh

_pdb_small_table_threshold

lower threshold level of table size for direct reads in a pdb

_pdb_transition_clean_bg_delay

delay in GEN0 to transition PDB to clean state

_pmem_exchange_cold_victim_threshold

worthy touch count threshold for a victim buffer to be exchanged into pmem

_pmem_small_table_threshold

lower threshold of PMEM table size as percentage to PMEM cache for direct reads

_pmemfs_alloc_dataptrs

Set PMEMfs to preallocate inode tree

_pmemfs_enable_spacetracking

Enable PMEMfs Space Accounting Checks

_pmemfs_shrink_level

Enable pmemstore shrink

_pmemfs_smallfile_threshold

Block count threshold for metedata

_post_run_job_evaluation

Control if jobs should evaluate at end of execution

_pqq_pdb_load_publish_threshold

difference in percentage controlling PDB load publish

_process_max_pred_increase

process SO max predicted increase

_process_percent_rampup_end

process SO percent rampup end

_process_percent_rampup_start

process SO percent rampup start

_process_prediction_failover_buffer

process prediction failover buffer

_process_save_prediction

save process prediction for next instance startup

_process_so_max_inc

process SO max inc

_profile_sensitive_users

Database Users with restricted password profile

_psdclog_enable

Mandatory Cloud Logging of PL/SQL Utility Packages Usages

_psdclog_threshold

Threshold for Cloud Logging of PL/SQL Utility Packages Usages

_psr_opt

options for standby pdb recovery

_px_adaptive_dist_nij_enabled

enable adaptive distribution methods for left non-inner joins

_px_extended_join_skew_handling

enables extended skew handling for parallel joins

_px_oneslave_per_instance_parse

send parse to one slave per instance

_px_parallelize_non_native_datatype

enable parallelization for non-native datatypes

_remote_http_port

HTTP port number registered with remote listener

_reset_increase_lmd_process

set to true to allow reset of _increase_lmd_process changes

_reset_increase_lms_process

set to true to allow reset of _increase_lms_process changes

_result_cache_do_recycle_period

Timeout value for DOs added through invalidation

_result_cache_global_send

Is global send conditional in RAC?

_result_cache_history_size

memory used to track PL/SQL function history

_result_cache_latch_count

number of result cache latches

_result_cache_load_rate

Simulated global load rate (bytes per 1/100 sec)

_result_cache_object_black_list

object numbers not allowed to use the result cache

_result_cache_use_hash_table

whether to use hash table for object tracking

_root_clone_skip_trigger

Skip trigger in Application Root Clone

_rsrc_cpu_count

CPU Count for allocating resources.

_runtime_index_key_length_check

allow runtime checking of index key length

_runtime_limit_parallel_fptr

run-time limit for for parallel first-pass recovery

_second_spare_pdb_parameter

second spare pdb parameter - integer

_securefile_shrink_enable_nowaitlck

Enable Securefile Shrink NOWAIT row locking

_securefile_shrink_hash_table_limit

Size limit on Securefile Lob Shrink state Hash table

_securefiles_dealloc_cfs

securefiles deallocate directly to CFS

_sess_sign_num_pools

session signature: number of pools

_sess_template_all_overflow

session template: put all attributes into overflow

_sess_template_cache_buckets

session template: number of cache buckets

_sess_template_enabled

session template: enabled

_sess_template_max_cache_size

session template: max cache size (in 1/100% of SGA)

_sess_template_new_lists

session template: number of new lists

_sess_template_purge_time_mins

session template: purge time (in minutes)

_sess_template_spares

session template: spares

_session_limit_percent_cap

session limit percent cap

_session_modp_list

send session's modified parameter list to client

_session_so_max_inc

session SO max inc

_seventeenth_spare_pdb_parameter

seventeenth spare pdb parameter - integer

_seventh_spare_pdb_parameter

seventh spare pdb parameter - integer

_seventieth_spare_pdb_parameter

seventieth spare pdb parameter - boolean

_shard_ddl_policy

DDL execution mode for shards

_shard_sesscache_cnt

enable session caching for shard SQL

_singleton_service_goodness_disabled

singleton srvc goodness

_sixteenth_spare_pdb_parameter

sixteenth spare pdb parameter - integer

_sixth_spare_pdb_parameter

sixth spare pdb parameter - integer

_sixtieth_spare_pdb_parameter

sixtieth spare pdb parameter - boolean

_sixty-eighth_spare_pdb_parameter

sixty-eighth spare pdb parameter - boolean

_sixty-fifth_spare_pdb_parameter

sixty-fifth spare pdb parameter - boolean

_sixty-first_spare_pdb_parameter

sixty-first spare pdb parameter - boolean

_sixty-fourth_spare_pdb_parameter

sixty-fourth spare pdb parameter - boolean

_sixty-ninth_spare_pdb_parameter

sixty-ninth spare pdb parameter - boolean

_sixty-second_spare_pdb_parameter

sixty-second spare pdb parameter - boolean

_sixty-seventh_spare_pdb_parameter

sixty-seventh spare pdb parameter - boolean

_sixty-sixth_spare_pdb_parameter

sixty-sixth spare pdb parameter - boolean

_sixty-third_spare_pdb_parameter

sixty-third spare pdb parameter - boolean

_skip_oradism_check

Switch on all features for the purpose of testing

_skip_sequence_cache_close_immediate

Skip sequence cache flush on pdb shutdown immediate

_smon_ofd_sleep_interval

smon sleep internval for undo ofd test

_spec_replace_locks_body

Lock body when replacing a package specification

_sqlexec_aggregation_settings

runtime settings for aggregation

_sqlexec_hash_aggr_small_mem_blocks

hash aggregation small initial memory footprint number of blocks

_sqlexec_hash_based_distagg_ser_civ_enabled

enable hash based distinct aggregation in serial/CIV queries

_sqlexec_hash_based_set_operation_enabled

enable/disable hash based set operation

_sqlexec_hash_rollup_enabled

enable hash rollup

_sqlexec_use_delayed_unpacking

enable/disable the usage of delayed unpacking

_strict_utl_http_smtp

Enforce strict URL checks on UTL_HTTP and UTL_SMTP Packages

_subquery_pruning_flags

subquery pruning flags

_swat_ver_mv_knob

Knob to control MV/REWRITE behavior

_symbol_no_translation

disable symbol tranlations in call stacks

_sync_error_handler

error handler function for Application Sync

_synchronous_rewrap_rac_ts_keys

if TRUE, synchronously rewrap TS keys in all nodes in MK rekey

_system_memory_simulate

system memory simulation mode, TRUE for hugetlbfs simulation

_tcpinfo_statistics_save_atexit

TCP Info Statistics Save At Exit

_temp_undo_disable_refresh_clone

is temp undo disabled on refreshable clone PDB

_tenth_spare_pdb_parameter

tenth spare pdb parameter - integer

_test_flashback_shrink

test flashback datafile shrink feature

_test_param_13

test parmeter 13 - boolean

_test_param_14

test parmeter 14 - string list

_test_param_15

test parmeter 15 - integer

_test_param_4_1

test parameter 4_1 - nonsys mod. string list

_test_param_pdb_spare

test parameter pdb spare

_test_param_spare

test parameter spare

_third_spare_pdb_parameter

third spare pdb parameter - integer

_thirteenth_spare_pdb_parameter

thirteenth spare pdb parameter - integer

_thirtieth_spare_pdb_parameter

thirtieth spare pdb parameter - string

_thirty-eighth_spare_pdb_parameter

thirty-eighth spare pdb parameter - string

_thirty-fifth_spare_pdb_parameter

thirty-fifth spare pdb parameter - string

_thirty-first_spare_pdb_parameter

thirty-first spare pdb parameter - string

_thirty-fourth_spare_pdb_parameter

thirty-fourth spare pdb parameter - string

_thirty-ninth_spare_pdb_parameter

thirty-ninth spare pdb parameter - string

_thirty-second_spare_pdb_parameter

thirty-second spare pdb parameter - string

_thirty-seventh_spare_pdb_parameter

thirty-seventh spare pdb parameter - string

_thirty-sixth_spare_pdb_parameter

thirty-sixth spare pdb parameter - string

_thirty-third_spare_pdb_parameter

thirty-third spare pdb parameter - string

_trace_suppress

suppresses matching trace for a given substring(prefix)

_trace_suppress_disable

Disable trace suppress feature

_ttc_annotations_level

enable ttc annotations

_twelfth_spare_pdb_parameter

twelfth spare pdb parameter - integer

_twentieth_spare_pdb_parameter

twentieth spare pdb parameter - integer

_twenty-eighth_spare_pdb_parameter

twenty-eighth spare pdb parameter - string

_twenty-fifth_spare_pdb_parameter

twenty-fifth spare pdb parameter - string

_twenty-first_spare_pdb_parameter

twenty-first spare pdb parameter - string

_twenty-fourth_spare_pdb_parameter

twenty-fourth spare pdb parameter - string

_twenty-ninth_spare_pdb_parameter

twenty-ninth spare pdb parameter - string

_twenty-second_spare_pdb_parameter

twenty-second spare pdb parameter - string

_twenty-seventh_spare_pdb_parameter

twenty-seventh spare pdb parameter - string

_twenty-sixth_spare_pdb_parameter

twenty-sixth spare pdb parameter - string

_twenty-third_spare_pdb_parameter

twenty-third spare pdb parameter - string

_txn_spare1

transaction spare variable1

_txn_spare2

transaction spare variable2

_txn_spare3

transaction spare variable3

_undo_ofd_enabled

enable ordered offline drop of undo segments for datafile shrink

_undo_ofd_excess

percent of excess undo segments to offline or drop

_undo_ofd_reserve

percent of excess undo segments to keep online

_unified_pga_block_size

Unified PGA internal block size

_unified_pga_gran_free_timeout

Granule free timeout

_unified_pga_gran_leak_timeout

Granule leak timeout

_unified_pga_list_count

Unified PGA internal list count

_unified_pga_max_pool_size

max size in bytes of the unified pga pool

_upgrade_pdb_on_open

Enable upgrading a PDB automatically on open

_ut_fast_lrg_prediction

use short interval for session SO prediction

_utlfile_dirpath

return Utl_File Accessible

_uts_disable_client_ip_trace

Disables the printing of client IP address in trace files

_uts_force_seclabel_prefix

Force output of trace record security label prefix

_write_renamed_datafile_name

print renamed datafile names to alert log

_xs_sidp_allow_sha1

XS SIDP allow use of SHA1

_zonemap_auto_candidate_table_min_size

Minimum size for a table to be candidate for an automatic zonemap

_zonemap_auto_clustering_ratio

Data clustering ratio in percent for automatic zonemap columns

_zonemap_refresh_within_load

Control the refresh of basic zonemaps during/after data load

 Parameters deprecated in Version 21c in comparison with 19c.

NAME

ISDEP

DESCRIPTION

lock_name_space

TRUE

lock name space used for generating lock names for standby/clone database

instance_groups

TRUE

list of instance group names

resource_manager_cpu_allocation

TRUE

Resource Manager CPU allocation

active_instance_count

TRUE

number of active instances in the cluster database

db_block_buffers

TRUE

Number of database blocks cached in memory

buffer_pool_keep

TRUE

Number of database blocks/latches in keep buffer pool

buffer_pool_recycle

TRUE

Number of database blocks/latches in recycle buffer pool

log_archive_start

TRUE

start archival process on SGA initialization

fast_start_io_target

TRUE

Upper bound on recovery reads

serial_reuse

TRUE

reuse the frame segments

rdbms_server_dn

TRUE

RDBMS's Distinguished Name

cursor_space_for_time

TRUE

use more memory in order to get faster execution

plsql_v2_compatibility

TRUE

PL/SQL version 2.x compatibility flag

plsql_debug

TRUE

PL/SQL debug

background_dump_dest

TRUE

Detached process dump directory

user_dump_dest

TRUE

User process dump directory

commit_write

TRUE

transaction commit log write behaviour

sql_trace

TRUE

enable SQL trace

parallel_adaptive_multi_user

TRUE

enable adaptive setting of degree for multiple user streams

asm_preferred_read_failure_groups

TRUE

preferred read failure groups

 Hidden Parameter Not Available in 21c in comparison with 19c.

PARAMETER

PARAMETER_DESCRIPTION

_arch_sim_mode

Change behavior of local archiving

_asm_enable_parity_datafile_creation

Enable parity datafiles creation

_auto_start_pdb_services

Automatically start all PDB services on PDB Open

_bug29274428_modsvc_call_out_enabled

one-hundred-and-forty-third spare parameter - boolean

_connect_string_params_after_logon_triggers

set connect string session parameters after logon triggers

_connect_string_params_unalterable

make connect string session parameters unalterable

_disable_thread_snapshot

Thread snapshot

_enable_auto_upgrade

Enable automatic PDB upgrade

_gc_async_receive

if TRUE, receive blocks asynchronously

_group_partition_data_for_impdp_ok

data pump import allows DATA_OPTIONS=GROUP_PARTITION_DATA

_hang_enable_nodeeviction

Enable Hang Manager node eviction

_hang_long_wait_time_threshold

Long session wait time threshold in seconds

_hcs_disable_cell_qry_meas_prune_opt

apply measure prune optimization to cell query

_hcs_disable_cell_qry_tmpls

no cell query templates for optimization

_hcs_disable_hord_in_oby_prune

prune levels if HIER_ORDER referenced only in ORDER BY

_hcs_disable_jback_opt_for_hord_in_oby

optimize analytic view joinback for HIER_ORDER

_hcs_disable_level_prune_gby

perform level pruning in group by

_hcs_disable_level_prune_vis_lvs

perform level pruning from visible leaves

_hcs_disable_pushed_preds_in_gen_sql

push sql query predicates into hierarchy targets

_hcs_disable_rmv_unref_top_opt

apply remove unref top blocks optimization to cell query

_hcs_disable_sp_jback_opt

optimize single parent joinback

_hcs_disable_tgt_depths_opt

apply target depths optimization

_hcs_enable_dynamic_cache

enable/disable av cache DYNAMIC definition

_hcs_enable_mem_trck

enable memory tracking

_hcs_enable_multi_parent_gen

generate hcs query using multi-parent aggregation

_kkpo_ctb_allow_vpd

allow VPD predicates in recursive SQL under CREATE TABLE

_ksipc_ipclw_spare_param1

ksipc ipclw spare parameter 1

_log_archive_avoid_memcpy

log archive avoid memcpy

_optimizer_auto_index_allow

Controls Auto Index

_optimizer_quarantine_sql

enable use of sql quarantine

_part_access_version_by_number

use version numbers to access versioned objects for partitioning

_pga_detail_combine_auto

combine auto and manual PGA memory detail snapshots

_reset_maxcap_history

reset maxcap history periods

_securefiles_increase_hbb

securefiles increase hbb

_session_fast_lrg_prediction

use short interval for session SO prediction

_session_prediction_interval

session SO prediction interval

_session_use_linear_prediction

use session SO lin-reg prediction

_session_use_periodic_prediction

use session SO periodic prediction

_show_mgd_recovery_state

Show internal managed recovery state

_size_of_status_table

modifying this hidden parameter, will modify the sizeof the v$gcr_status table

_so_max_inc

SO max inc

_ta_lns_wait_for_arch_log

LNS Wait time for archived version of ORL

_tablespace_encryption_default_algorithm

default tablespace encryption block cipher mode

_unified_audit_flush_interval

Unified Audit SGA Queue Flush Interval

_unified_audit_flush_threshold

Unified Audit SGA Queue Flush Threshold

_workload_attributes_spare_param

connect string workload behavior spare param

 Parameters becomes Obsolete in Version 21c in comparison to 19c.

PARAMETER

PARAMETER_DESCRIPTION

sec_case_sensitive_logon

case sensitive password enabled for logon                       

REMOTE_OS_AUTHENT

allow non-secure remote clients to use auto-logon accounts      

cluster_database_instances

number of instances to use for sizing cluster db SGA structures 

_group_partition_data_for_impdp_ok

data pump import allows DATA_OPTIONS=GROUP_PARTITION_DATA

_zonemap_auto_processing

Control the processing of automatic zonemaps                    

_part_access_version_by_number

use version numbers to access versioned objects for partitioning

 Note: Parameter "_zonemap_auto_processing" was introduced in 20c Preview version and made obsolete in 21c innovation version.

The details of the Parameters are collected from the database views.

View_Name

Details

V$OBSOLETE_PARAMETER        

This view shows the information on database Obsolete parameters.

V$PARAMETER        

This view shows the information for the parameter value that effects for current session level parameter.

V$PARAMETER2        

This view is similar to V$PARAMETER view, only difference is view output for value column. Multiple value for same parameter are shown in this view with multiple rows. Example, multiple values for control_files.

V$PARAMETER_VALID_VALUES       

This view displays a list of valid values for list parameters.

V$SPPARAMETER        

Its shows the information of SPFILE, if the instance is not brought up with SPFILE then the value of ISSPECIFIED column will be shown as "FALSE". This view also saves the parameter value altered with scope as spfile.

V$SYSTEM_PARAMETER        

This view contains the instance level parameters, a new user session inherits the parameters from this view. This view also saves the parameter value altered with scope as memory or both.

V$SYSTEM_PARAMETER2        

This view shows the system level parameters.

V$SYSTEM_RESET_PARAMETER       

This view Shows the value of a parameter if you run alter system reset to clear it from spfile.

V$SYSTEM_RESET_PARAMETER2      

This view is similar to V$SYSTEM_RESET_PARAMETER view, only difference is in output of value column like of V$PARAMETER2.

X$KSPPI

This is a Kernel Service view that have the information on database hidden parameter.

X$KSPPCV

This is a Kernel Service view that have the current session level hidden parameter value.

X$KSPPSV

This is a Kernel Service view that have the system level hidden parameter value.


Conclusion:

After going through this blog the information on new parameter introduced and deprecated will be clear and users will be able to use the parameters for Database Version 21c for building a healthy and well performed database.

In the upcoming blogs I will try to illustrate the performance difference for using the database parameters.

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