前回に続き、Oracle Database19cと23cの隠しパラメータを比較した結果の纏め。今回は19cと比較して23cで新規に登場した隠しパラメータのうち、_l～_rから始まる隠しパラメータを記載する。
※19cとの比較による新規隠しパラメータの抽出であるため、20c,21cで新規登場したものも23cでの新規として記載する。隠しパラメータ数が多いため、PCでの閲覧推奨。
5.新規隠しパラメータ(_l* ～ _r*)
新規の隠しパラメータは1388個存在し、_l* ～ _r*な隠しパラメータは361個存在した。
| パラメータ名 | デフォルト値 | ALTER SESSION | ALTER SYSTEM | パラメータ概要 |
|---|---|---|---|---|
| _ldap_use_all_direct_groups_only | TRUE | FALSE | IMMEDIATE | LDAP use all direct groups only |
| _ldap_warning_on_multi_shared_mappings | FALSE | FALSE | IMMEDIATE | LDAP warning on multiple shared mappings |
| _ldr_pga_proc_lim | 0 | TRUE | IMMEDIATE | pga proc limit, beyond which new partition loads are delayed |
| _leader_pdb | FALSE | FALSE | IMMEDIATE | enable leader PDB functionality |
| _leader_pdb_guid | FALSE | IMMEDIATE | GUID of Leader PDB | |
| _lgwr_delay_slave_write | FALSE | FALSE | FALSE | Enable LGnn write delay for testing |
| _lgwr_delay_write_csec | 300 | FALSE | FALSE | If LGWR write delays are enabled, delay each write by this amount |
| _lgwr_delay_write_interval | 10 | FALSE | FALSE | If LGWR write delays are enabled, delay every Nth write |
| _lgwr_thick_mode_config | 1:2:1536:8192:1500 | FALSE | IMMEDIATE | adaptive overlapped writes thick mode configuration |
| _lgwr_thin_mode_config | 1:256:256:100:750 | FALSE | IMMEDIATE | adaptive overlapped writes thin mode configuration |
| _link_to_leader_pdb | FALSE | IMMEDIATE | database link to Leader PDB | |
| _link_ts_force_online | TRUE | TRUE | IMMEDIATE | force linked tablespace to be online |
| _listener_registration_retry_secs | 60 | FALSE | IMMEDIATE | listener registration retry time (in seconds) |
| _lm_async_da | FALSE | FALSE | FALSE | enable async da requests |
| _lm_async_pdb_open | 0 | FALSE | FALSE | if TRUE enables asynchronous pdb open in DLM |
| _lm_comm_monitor_pending_sends | 0 | FALSE | IMMEDIATE | Pending sends monitoring |
| _lm_comm_receive_buffer_multiple | 2 | FALSE | FALSE | Additional receive buffer multiple |
| _lm_comm_send_proxy_bufr_return_mode | 1 | FALSE | FALSE | Send proxy buffer return mode |
| _lm_comm_send_proxy_nr_delay | 10 | FALSE | IMMEDIATE | Send proxy delay before sending NULLREQ |
| _lm_comm_send_proxy_send_comp_wait | 100 | FALSE | IMMEDIATE | Send proxy wait on send completion |
| _lm_comm_send_proxy_send_wait | 50 | FALSE | IMMEDIATE | Send proxy wait per sends |
| _lm_comm_send_proxy_tkt_return | TRUE | FALSE | IMMEDIATE | Allow send proxy to return tickets |
| _lm_comm_slow_op_spx_loop_threshold | 30000 | FALSE | IMMEDIATE | GES comm slow spx operation loop threshold in microsec |
| _lm_comm_tkts_adpt_rsv | 1 | FALSE | IMMEDIATE | Adpative ticketing reserve multiple |
| _lm_da_win_enable | TRUE | FALSE | FALSE | enable da windowing |
| _lm_da_window | 1 | FALSE | IMMEDIATE | number of windows in domain action |
| _lm_da_window_interval | 0 | FALSE | IMMEDIATE | Interval in centiseconds between each domain action window |
| _lm_default_failure_action | 0 | FALSE | IMMEDIATE | default failure action |
| _lm_drm_pdb_on | TRUE | FALSE | FALSE | only pdb members participate in DRM |
| _lm_drm_test_duration_limit | 5 | FALSE | IMMEDIATE | set drm test duration limit (secs time/object size) |
| _lm_enable_pdb_abort | 1 | FALSE | IMMEDIATE | enable pdb abort as default failure action |
| _lm_gcs_rht_alloc_size | 4096 | FALSE | FALSE | gcs rht allocation chunk size |
| _lm_ges_rht_alloc_size | 4096 | FALSE | FALSE | ges rht allocation chunk size |
| _lm_ges_rht_mem_pct | 15 | FALSE | IMMEDIATE | options to size RHT structures per pdb |
| _lm_hb_lgio_timeout | FALSE | IMMEDIATE | LGWR io timeout in seconds | |
| _lm_hist_bucket_trigger | 500 | FALSE | IMMEDIATE | LM trigger to produce trace bucket dump in ms |
| _lm_hist_dump_trigger | 100 | FALSE | IMMEDIATE | LM trigger to produce diagnostic in ms |
| _lm_hist_opcode_trigger | 0 | FALSE | IMMEDIATE | LM opcode to produce trace bucket dump |
| _lm_hvenqid4_opt | 1 | FALSE | FALSE | pass setmaster in id4 of HV enqueue name |
| _lm_killproc_timeout | 120 | FALSE | IMMEDIATE | lazy domain killproc timeout in seconds |
| _lm_kjbdomlzdomscn_interval | 1 | FALSE | FALSE | kjbdomlzdomscn() interval time in seconds |
| _lm_mp_additional_big_buffers | 20 | FALSE | FALSE | GES MP extra big buffers per pool |
| _lm_mp_additional_reg_buffers | 20 | FALSE | FALSE | GES MP extra regular buffers per pool |
| _lm_mp_expand_big_pool_percent | 1 | FALSE | IMMEDIATE | GES MP expand big pool |
| _lm_mp_expand_reg_pool_percent | 5 | FALSE | IMMEDIATE | GES MP expand regular pool |
| _lm_mp_share_lms_pools | TRUE | FALSE | FALSE | GES MP share LMS pools with critical BGs |
| _lm_mp_small_lms_pools | TRUE | FALSE | FALSE | GES MP small regular pool for LMS when not sharing |
| _lm_mwin_req_queue_max_size | 4000 | FALSE | IMMEDIATE | maximum size of multiwindow request queue |
| _lm_new_esm | 1 | FALSE | FALSE | use new enter server mode code |
| _lm_nodrm_service_pct | 95 | FALSE | IMMEDIATE | minimum nonsingleton service access percentage to disable drm |
| _lm_pdb_weight_opts | 90 | FALSE | IMMEDIATE | options to size RHT structures per pdb |
| _lm_rac_spare_dp11 | 0 | FALSE | IMMEDIATE | rac parameter dp11 |
| _lm_rac_spare_dp12 | 0 | FALSE | IMMEDIATE | rac parameter dp12 |
| _lm_rac_spare_dp13 | 0 | FALSE | IMMEDIATE | rac parameter dp13 |
| _lm_rac_spare_dp14 | 0 | FALSE | IMMEDIATE | rac parameter dp14 |
| _lm_rac_spare_dp15 | 0 | FALSE | IMMEDIATE | rac parameter dp15 |
| _lm_rac_spare_dp16 | 0 | FALSE | IMMEDIATE | rac parameter dp16 |
| _lm_rac_spare_dp17 | 0 | FALSE | IMMEDIATE | rac parameter dp17 |
| _lm_rac_spare_dp18 | 0 | FALSE | IMMEDIATE | rac parameter dp18 |
| _lm_rac_spare_dp19 | 0 | FALSE | IMMEDIATE | rac parameter dp19 |
| _lm_rac_spare_dp20 | 0 | FALSE | IMMEDIATE | rac parameter dp20 |
| _lm_rac_spare_dp21 | 0 | FALSE | IMMEDIATE | rac parameter dp21 |
| _lm_rac_spare_dp22 | 0 | FALSE | IMMEDIATE | rac parameter dp22 |
| _lm_rac_spare_dp23 | 0 | FALSE | IMMEDIATE | rac parameter dp23 |
| _lm_rac_spare_dp24 | 0 | FALSE | IMMEDIATE | rac parameter dp24 |
| _lm_rac_spare_dp25 | 0 | FALSE | IMMEDIATE | rac parameter dp25 |
| _lm_rac_spare_dp26 | 0 | FALSE | IMMEDIATE | rac parameter dp26 |
| _lm_rac_spare_dp27 | 0 | FALSE | IMMEDIATE | rac parameter dp27 |
| _lm_rac_spare_dp28 | 0 | FALSE | IMMEDIATE | rac parameter dp28 |
| _lm_rac_spare_dp29 | 0 | FALSE | IMMEDIATE | rac parameter dp29 |
| _lm_rac_spare_dp30 | 0 | FALSE | IMMEDIATE | rac parameter dp30 |
| _lm_receiver_type | 0 | FALSE | IMMEDIATE | receiver thread type performing receive function |
| _lm_recovery_pdbw_reduction | 4 | FALSE | IMMEDIATE | recovery member pdbw reduction |
| _lm_req_max_life | 36000 | FALSE | IMMEDIATE | maximum life time of request in seconds |
| _lm_resource_recycle_cnt | 4 | FALSE | IMMEDIATE | GES: number of resources to recycle optimization |
| _lm_share_opt_async_open_pdb | TRUE | FALSE | IMMEDIATE | if TRUE enables s-opt with async open pdb |
| _lm_sp_slave_mode | 0 | FALSE | IMMEDIATE | sendproxy thread operation mode |
| _lm_sq_batch_waittick_worker | 10 | FALSE | IMMEDIATE | GES send queue batching waittime for worker in tick |
| _lm_worker_mode | 0 | FALSE | IMMEDIATE | LMS worker thread mode |
| _lm_worker_threads | 0 | FALSE | IMMEDIATE | number of LMS worker threads |
| _lmhb_max_dynamic_hb | 10 | FALSE | IMMEDIATE | max number of proc heartbeats that can be dynamically monitored |
| _lmhb_min_pct_hbcnt | 0 | FALSE | IMMEDIATE | minimum heartbeat ticks to not be flagged as hung (percent) |
| _lmhb_select_final_blkr | FALSE | FALSE | IMMEDIATE | selects ultimate non-fatal blocker in hang chain (if present) |
| _lob_session_parameters | PGA_SMART_LOBS_LIMIT:75 | TRUE | FALSE | Controls LOBs behavior |
| _lock_get_soft_assert_timeout | 900 | FALSE | IMMEDIATE | lock get soft assert timeout in seconds, 0 to disable |
| _lockdown_exec_skip_invalidation | FALSE | TRUE | IMMEDIATE | Skip dependent lib-cache object invalidation upon disabling execution |
| _lockdown_execution_check | FALSE | TRUE | IMMEDIATE | Check if lockdown execution check feature is enabled in PDB |
| _log_archive_dest_force_async | FALSE | FALSE | IMMEDIATE | force async on service destinations |
| _log_client_ip_address_to_alert | FALSE | FALSE | IMMEDIATE | Log Client IP Address to alert file for each login |
| _log_switch_tracing_iterations | 5 | FALSE | IMMEDIATE | no. of iterations to trace after logswitch timeout |
| _log_switch_tracing_timeout | 200 | FALSE | IMMEDIATE | dbwr to trace after logswitch timeout in secs |
| _logminer_parallel_read | TRUE | FALSE | IMMEDIATE | LogMiner parallel read |
| _low_priority_processes | NONE | FALSE | FALSE | Low Priority Process Name Mask |
| _lowest_priority_processes | NONE | FALSE | FALSE | Lowest Priority Process Name Mask |
| _lreg_max_update_history | 3600 | FALSE | FALSE | lreg max update history |
| _lreg_significant_change | 3 | FALSE | IMMEDIATE | lreg significant change |
| _lreg_update_lag_mins | 10 | FALSE | IMMEDIATE | lreg update lag (in minutes) |
| _map_service_name | FALSE | TRUE | IMMEDIATE | Map service names between Proxy PDB and Referenced PDB |
| _max_def_granule_size | 67108864 | FALSE | FALSE | maximum default SGA granule size |
| _max_dist_bt_chains | 8 | FALSE | IMMEDIATE | maximum number of chains for distributed transaction |
| _max_dynamic_processes | 10000 | FALSE | FALSE | max dynamic processes count |
| _max_flashback_shrink_size | 1048576 | FALSE | IMMEDIATE | maximum size(in KBs) a datafile can be shrunk with flashback DB |
| _max_gg_extracts | 65535 | FALSE | IMMEDIATE | maximum limit for goldengate extract instances |
| _max_physmem_perc_um | 90 | FALSE | FALSE | maximum percentage of physical memory for Unified Memory |
| _max_small_page_sga_size | 0 | FALSE | FALSE | Maximum SGA size with small pages |
| _maxval_job_queue_processes | FALSE | IMMEDIATE | Maximum value of job queue slave processes parameter for the PDB | |
| _mdapi_transform_engine | LPX | FALSE | IMMEDIATE | DDL transformation engine |
| _memoptimize_write_shrink_minsize | TRUE | FALSE | IMMEDIATE | shrinks Ingest Global Area size down to min size |
| _memoptimize_writes_no_wait | FALSE | TRUE | FALSE | enable no wait conventional insert path for memoptimize write |
| _memory_broker_marginal_utility_imc | 6 | FALSE | IMMEDIATE | Marginal Utility threshold pct for imc |
| _memory_broker_shrink_imc | 15 | FALSE | IMMEDIATE | memory broker allow policy to shrink imc pool |
| _memory_per_cpu_count | 0 | FALSE | FALSE | memory per cpu count |
| _mga_pid_root_head_count | 16 | FALSE | IMMEDIATE | mga pid root head count |
| _mle_compilation_dump_graph_on_crash | FALSE | TRUE | IMMEDIATE | dump compilation graphs to the trace file when compilation crashes in MLE |
| _mle_compilation_errors_are_fatal | FALSE | TRUE | IMMEDIATE | failed compilations are fatal for MLE |
| _mle_compilation_sync | FALSE | TRUE | IMMEDIATE | force compilation to be synchronous for MLE |
| _mle_compile_immediately | FALSE | TRUE | IMMEDIATE | force compilation for MLE |
| _mle_enable_compilation | TRUE | FALSE | IMMEDIATE | enable runtime compilation for MLE |
| _mle_enable_recursion | TRUE | TRUE | FALSE | enable recursive/reentrant MLE |
| _modify_protected_profile_parameters | FALSE | IMMEDIATE | List of password parameters allowed to be modified for protected profile | |
| _mt_redo_log_record_wakeup_interval | 1440 | FALSE | IMMEDIATE | Wake up time in minutes to purge redo log table records |
| _mt_rfs_flush_header_interval | 5 | FALSE | IMMEDIATE | MT flush header interval |
| _mt_rfs_gap_interval | 720 | FALSE | IMMEDIATE | MT Gap limit |
| _mt_rfs_register_lag_seq | 24 | FALSE | IMMEDIATE | MT Register Lag Sequence |
| _multi-statement_pdml_support | PDML | FALSE | IMMEDIATE | is multi-statement PDML allowed (remove touch-once restriction) |
| _mutex_skip_spin_waiter_count | 20 | FALSE | IMMEDIATE | Active waiter count to skip mutex spin |
| _mv_master_lock_timeout | 3 | FALSE | IMMEDIATE | timeout that mv create/drop waits to lock the master table |
| _nanovos_library | FALSE | FALSE | Nanovos instance object path | |
| _nanovos_name | FALSE | FALSE | Nanovos instance name | |
| _nanovos_type | FALSE | FALSE | Nanovos instance type | |
| _ndb_enable | FALSE | FALSE | FALSE | Native Database Blockchain Enable |
| _need_administer_fine_grained_audit_policy_for_fga | TRUE | FALSE | IMMEDIATE | Check ADMINISTER FINE GRAINED AUDIT POLICY privilege for administering FGA policy |
| _need_administer_redaction_policy_for_redact | TRUE | FALSE | IMMEDIATE | Check ADMINISTER REDACTION POLICY privilege for administering REDACT policy |
| _need_administer_row_level_security_policy_for_rls | TRUE | FALSE | IMMEDIATE | Check ADMINISTER ROW LEVEL SECURITY POLICY privilege for administering VPD policy |
| _need_create_table_privilege_for_redact | FALSE | FALSE | IMMEDIATE | Check CREATE TABLE privilege for administering REDACT policy |
| _netldp_common_users_as_local | FALSE | IMMEDIATE | List of common users to be treated as local for network lockdown | |
| _next_constraint_cache_size | 5 | FALSE | IMMEDIATE | size of _NEXT_CONSTRAINT cache |
| _nineteenth_spare_pdb_parameter | TRUE | IMMEDIATE | nineteenth spare pdb parameter - integer | |
| _ninth_spare_pdb_parameter | TRUE | IMMEDIATE | ninth spare pdb parameter - integer | |
| _non_app_cross_con_collection | FALSE | TRUE | IMMEDIATE | enable cross container collection for non-application objects |
| _non_blocking_hard_parse_min_extend_time | 2 | FALSE | IMMEDIATE | minimum additional lifetime added to cursor |
| _not_waiting_significant_CPU | 10 | FALSE | FALSE | percent of CPU time when not in a wait which is significant |
| _num_undostat_intervals | 576 | FALSE | FALSE | number of intervals for undo statistics in SGA |
| _NUMA_pool_reservation_trace | FALSE | FALSE | FALSE | Show NUMA pool reservations at startup |
| _number_ksim_group_req_threshold | 64 | FALSE | IMMEDIATE | ksim maximum number of group operations requests |
| _numgrans_per_file | 64 | FALSE | FALSE | Number of granules per SGA file |
| _nusa_data_containers | FALSE | IMMEDIATE | list of data containers in the nusa universe | |
| _nusa_metadata_store | FALSE | IMMEDIATE | metadata store in nusa | |
| _nusa_remote_data_containers | FALSE | IMMEDIATE | disk groups with remote access for NUSA | |
| _nvm_asm_dispatchers | 1 | FALSE | FALSE | number of NVM Dispatcher Slaves for ASM |
| _nvm_dbw_dispatchers | 1 | FALSE | FALSE | number of NVM Dispatcher Slaves for DBWRs |
| _nvmeof_zcopy_enable | FALSE | FALSE | FALSE | Enable Zero Copy for NVMeoF |
| _object_activity_control | 0 | TRUE | IMMEDIATE | controls tracing for object activity tracking system (OATS) |
| _object_activity_disable | 0 | TRUE | IMMEDIATE | disables some object activity tracking (OATS) |
| _object_activity_tracking | TRUE | TRUE | IMMEDIATE | enable object activity tracking system (OATS) |
| _objectstore_odm_segment_size | 0 | TRUE | IMMEDIATE | Internal variable Swift DLO segment size for ODM object store lib |
| _obsolete_result_cache_mode | MANUAL | TRUE | IMMEDIATE | USERS SHOULD NOT SET THIS! Used for old qksced parameterof result_cache_mode |
| _ofs_read_buffer_size | 1031680 | FALSE | IMMEDIATE | OFS read ahead buffer size in bytes |
| _ogg_online_ddl | TRUE | FALSE | IMMEDIATE | ogg online ddl marker |
| _one-hundred-and-forty-first_spare_parameter | FALSE | TRUE | IMMEDIATE | one-hundred-and-forty-first spare parameter - boolean |
| _one-hundred-and-forty-second_spare_parameter | FALSE | TRUE | IMMEDIATE | one-hundred-and-forty-second spare parameter - boolean |
| _one-hundred-and-forty-third_spare_parameter | FALSE | TRUE | IMMEDIATE | one-hundred-and-forty-third spare parameter - boolean |
| _onl_ddl_progress | 3 | TRUE | IMMEDIATE | track progress of online ddl |
| _onl_pmo_wait_query | 0 | TRUE | IMMEDIATE | online pmos wait for queries after swapping partitions |
| _onl_pmo_wait_timeout | 0 | TRUE | IMMEDIATE | online pmos wait for queries after swapping partitions timeout |
| _online_ddl_delay | 200 | TRUE | IMMEDIATE | centisecond delay for online DDL to allow cursor recompliation |
| _online_ddl_domain_index_flags | 1 | TRUE | IMMEDIATE | flags for domain indexes during online DDLs |
| _online_direct_load | 2 | TRUE | IMMEDIATE | Online Direct Load |
| _online_pmo_global_index_flags | 0 | TRUE | IMMEDIATE | flags for global indexes during partition maintenance DDLs |
| _online_pmo_global_index_method | CLEANUP ONLY | TRUE | IMMEDIATE | Unique global index method for partition maintenance DDLs |
| _optimize_dvconfig_cloudpdb | FALSE | FALSE | IMMEDIATE | Optimize Database Vault setup for cloud PDB |
| _optimize_tbsquota_ddl | TRUE | FALSE | IMMEDIATE | Optimize tablespace quota for user DDL |
| _optimizefsio | TRUE | IMMEDIATE | Test env file i/o setting | |
| _optimizer_diag_stats | TRUE | FALSE | IMMEDIATE | enable/disable populating stats diagnosis tables |
| _optimizer_exists_to_any_rewrite | TRUE | TRUE | IMMEDIATE | consider exists-to-any rewrite of subqueries |
| _optimizer_force_error_CBQT | TRUE | IMMEDIATE | force assert within a CBQT transformation | |
| _optimizer_force_error_hash | TRUE | IMMEDIATE | force assert if hash of the error message equal to the parameter | |
| _optimizer_force_error_state | TRUE | IMMEDIATE | force assert in init phase, final phase or a candidate state | |
| _optimizer_nested_loop_join | on | TRUE | IMMEDIATE | favor/unfavor nested loop join |
| _optimizer_push_gby_into_union_all | TRUE | TRUE | IMMEDIATE | consider pushing down group-by into union-all branches |
| _optimizer_subsume_vw_sq | on | TRUE | IMMEDIATE | consider subsumption of views or subqueries |
| _optimizer_unnest_update_set_subq | on | TRUE | IMMEDIATE | enables unnesting of subquery in set for update |
| _optimizer_use_stats_models | FALSE | TRUE | IMMEDIATE | use optimizer statistics extrapolation models |
| _optimizer_wc_filter_pushdown | TRUE | TRUE | IMMEDIATE | enable/disable with clause filter predicate pushdown |
| _oracle_script_counter | 0 | TRUE | FALSE | Helper parameter to set the value of _oracle_script counter |
| _os_nice_high | 10 | FALSE | FALSE | OS high nice level |
| _os_nice_highest | 0 | FALSE | FALSE | OS highest nice level |
| _os_nice_low | 30 | FALSE | FALSE | OS low nice level |
| _os_nice_lowest | 39 | FALSE | FALSE | OS lowest nice level |
| _os_nice_normal | 20 | FALSE | FALSE | OS normal nice level |
| _os_sched_low_priority | 1 | FALSE | FALSE | OS low priority level |
| _os_sched_lowest_priority | 1 | FALSE | FALSE | OS lowest priority level |
| _os_sched_normal_priority | 1 | FALSE | FALSE | OS normal priority level |
| _os_sched_use_nice | TRUE | FALSE | FALSE | With this set to TRUE, the scheduling policy will be SCHED_OTHER as a default, and nice value alone will be modified to change process priority |
| _parallel_frz_step_reconfig | 0 | FALSE | IMMEDIATE | parallel rs work for freeze step for instance reconfig. |
| _parallel_server_memory_threshold | 0 | FALSE | IMMEDIATE | max memory threshold for idle PX server to exit |
| _parallel_server_resiliency | 1 | TRUE | IMMEDIATE | enable resilient execution of parallel query |
| _part_layer_performance_trace | 0 | TRUE | IMMEDIATE | diagnostic improvements for performence issues |
| _partial_log_preserve_space | TRUE | TRUE | IMMEDIATE | use only required space for partial archive logs |
| _partition_by_expression | FALSE | TRUE | IMMEDIATE | allow partition by expression |
| _partition_key_errmsg_limit | 128 | TRUE | IMMEDIATE | limit on the partition key string included in error messages |
| _partition_key_errtrc_limit | 16384 | TRUE | IMMEDIATE | limit on the partition key string written to trace file |
| _partn_blackbox_size | 16384 | TRUE | IMMEDIATE | partitioning blackbox bucket size |
| _path_prefix_create_dir | TRUE | TRUE | IMMEDIATE | Create path in file system for CREATE DIRECTORY with PATH_PREFIX |
| _path_prefix_override_dir | NONE | TRUE | FALSE | Override directory for PATH_PREFIX in PDB |
| _pdb_char_set_intconv | FALSE | TRUE | IMMEDIATE | Enforce internal_convert for PDB character set conversion |
| _pdb_clone_preserve_guid | FALSE | TRUE | FALSE | Use same guid for a pdb clone |
| _pdb_close_immediate_kill_batchsize | 1000 | TRUE | FALSE | batch size for killing sessions inside the PDB |
| _pdb_component_violation_restricted | FALSE | IMMEDIATE | Components allowed to have mismatch between CDB$Root and PDB | |
| _pdb_create_use_sysoper_conn | FALSE | TRUE | IMMEDIATE | spread file copy slaves across instances |
| _pdb_datapatch_violation_restricted | TRUE | TRUE | IMMEDIATE | Open pdb in restricted mode for datapatch error violation |
| _pdb_file_copy_affinitize | FALSE | TRUE | IMMEDIATE | spread file copy slaves across instances |
| _pdb_file_copy_buffers | 8 | TRUE | IMMEDIATE | number of buffers to use for pdb file copy |
| _pdb_force_cfd | FALSE | FALSE | IMMEDIATE | Force DB_CREATE_FILE_DEST path for all datafiles in PDB |
| _pdb_hybrid_read_only | FALSE | TRUE | IMMEDIATE | Hybrid read only mode allows CDB common user to patch the PDB |
| _pdb_ktg_buffer_size | 16 | TRUE | IMMEDIATE | KTG buffer size (in KB) to store inmemory traces |
| _pdb_lifespan_callout | NONE | TRUE | IMMEDIATE | PL SQL Procedure to import lifespan |
| _pdb_local_undo_tablespace_init_size | 100000000 | TRUE | IMMEDIATE | Initial size for undo tablespace |
| _pdb_lockdown_error_message | FALSE | TRUE | IMMEDIATE | Enable pdb lockdown specific error message |
| _pdb_media_rcv_parallelism | 0 | TRUE | IMMEDIATE | PDB media recovery parallelism |
| _pdb_oper_trace_threshold | 600 | TRUE | IMMEDIATE | PDB operations timing trace threshold |
| _pdb_oper_trace_threshold_softassert | FALSE | TRUE | IMMEDIATE | PDB operations timing threshold soft assert |
| _pdb_read_only_refresh | FALSE | TRUE | IMMEDIATE | allow refresh when pdb is open r/o |
| _pdb_refresh_apply_master_key_rekey | TRUE | TRUE | IMMEDIATE | Apply master rekey marker during pdb refresh |
| _pdb_refresh_remote_logs_path | TRUE | IMMEDIATE | Location of archive logs to use for pdb refresh | |
| _pdb_refresh_scn_to_seq_exttbl | NONE | TRUE | IMMEDIATE | external table name to use convert scn to thread#,seq# |
| _pdb_refresh_use_dblink_to_catalog | FALSE | TRUE | IMMEDIATE | Use central catalog for pdb refresh |
| _pdb_refresh_use_local_logs | TRUE | TRUE | IMMEDIATE | Use local logs for pdb refresh |
| _pdb_replay_param_allowlist | NONE | FALSE | IMMEDIATE | pdb replay parameter allow list |
| _pdb_replay_param_blocklist | NONE | FALSE | IMMEDIATE | pdb replay parameter block list |
| _pdb_replay_param_mode | DISABLED | FALSE | IMMEDIATE | pdb replay parameter mode |
| _pdb_service_name_convert | FALSE | IMMEDIATE | service name convert patterns and strings for per PDB clone | |
| _pdb_skiplist_apply_callout | NONE | TRUE | IMMEDIATE | PL SQL Procedure name to import skiplist |
| _pdb_skiplist_redogen_callout | NONE | TRUE | IMMEDIATE | PL SQL Procedure name to export skiplist |
| _pdb_small_table_threshold | FALSE | FALSE | lower threshold level of table size for direct reads in a pdb | |
| _pdb_transition_clean_bg_delay | 0 | FALSE | IMMEDIATE | delay in GEN0 to transition PDB to clean state |
| _pdb_trigger_user | TRUE | IMMEDIATE | user to execute pdb trigger | |
| _pdbopen_fixedtablestats | FALSE | FALSE | FALSE | gather fixed table stats at PDB open |
| _pdc_adaptive | FALSE | FALSE | FALSE | pmem direct commit adaptively determine percent of ORL-only txns |
| _pdc_adaptive_evaluation_delta | 10 | FALSE | IMMEDIATE | pmem direct commit adaptive txn eval. delta |
| _pdc_adaptive_evaluation_duration | 10 | FALSE | IMMEDIATE | pmem direct commit adaptive adaptive eval. duration (percent) |
| _pdc_adaptive_evaluation_interval | 60 | FALSE | IMMEDIATE | pmem direct commit adaptive adaptive eval. interval (in seconds) |
| _pdc_adaptive_evaluation_margin | 5 | FALSE | IMMEDIATE | pmem direct commit adaptive txn evaluation margin |
| _pdc_adaptive_evaluation_successes | 2 | FALSE | IMMEDIATE | pmem direct commit adaptive txn eval. successes |
| _pdc_concurrency | 4 | FALSE | FALSE | pmem direct commit concurrency |
| _pdc_file_clear | FALSE | FALSE | FALSE | clear pmem direct commit file when redo thread is opened |
| _pdc_imu_pct | 0 | FALSE | FALSE | percentage of IMU ORL-only transactions |
| _pdc_imud_flush | TRUE | FALSE | FALSE | flush an imu txn's downgrade redo immediately |
| _pdc_inst_bocs | 1 | FALSE | FALSE | number of per-instance persistent memory log buffer bocs |
| _pdc_max_mirrors | 2 | FALSE | FALSE | max number of pmem direct commit mirrors |
| _pdc_min_mirrors | 2 | FALSE | FALSE | min number of pmem direct commit file mirrors |
| _pdc_msrdma | TRUE | FALSE | FALSE | enable pmem direct commit msrdma |
| _pdc_non_imu_pct | 0 | FALSE | FALSE | percentage of non-IMU ORL-only transactions |
| _pdc_plb_stealing | TRUE | FALSE | FALSE | enable pmem direct commit plb stealing |
| _pdc_ptn_unit_size | 65536 | FALSE | FALSE | pmem direct commit file ptn unit size |
| _pdc_read_full_ptn | FALSE | FALSE | FALSE | read entire pmem direct commit file ptn when resilvering |
| _pdc_reconfig_interval | 30 | FALSE | IMMEDIATE | How long RECO waits before strand file mirror reconfig check (min) |
| _pdc_remove_all_files | 0 | FALSE | FALSE | remove PMEM strand files during mount |
| _pdc_resilver | TRUE | FALSE | FALSE | enable resilvering of online log from pmem direct commit file |
| _pdc_resilver_single | FALSE | FALSE | FALSE | create a single strand lwn during resilvering from pmem |
| _pdc_simulation | FALSE | FALSE | FALSE | allow a simulated pmem direct commit file |
| _pdc_test_hook | 0 | FALSE | FALSE | pmem direct commit testing hook |
| _pdc_txn_time | 5 | FALSE | FALSE | max time in seconds before a txn logs redo only to the online log |
| _pdc_units_per_ptn | 4 | FALSE | FALSE | pmem direct commit file units per ptn |
| _pdc_use_partnership_map | TRUE | FALSE | FALSE | enable partnership map for mirror placement |
| _plan_verify_absolute_margin | 100000 | TRUE | IMMEDIATE | Absolute performance criterion for evolving plan baselines |
| _plsql_bypass_strict_semantics | FALSE | TRUE | IMMEDIATE | Bypass PL/SQL semantics to resolve 2-part name as schema.type after package.type fails. |
| _plsql_max_frame_count | 0 | FALSE | IMMEDIATE | PL/SQL maximum call nesting depth |
| _pmem_exchange_cold_victim_threshold | 0 | FALSE | IMMEDIATE | worthy touch count threshold for a victim buffer to be exchanged into pmem |
| _pmem_small_table_threshold | 20 | TRUE | DEFERRED | lower threshold of PMEM table size as percentage to PMEM cache for direct reads |
| _pmemfs_alloc_dataptrs | 1 | TRUE | IMMEDIATE | Set PMEMfs to preallocate inode tree |
| _pmemfs_enable_spacetracking | FALSE | TRUE | IMMEDIATE | Enable PMEMfs Space Accounting Checks |
| _pmemfs_shrink_level | 0 | FALSE | IMMEDIATE | Enable pmemstore shrink |
| _pmemfs_smallfile_threshold | 1024 | FALSE | IMMEDIATE | Block count threshold for metedata |
| _pmon_mutex_cleanup | 1 | FALSE | IMMEDIATE | PMON cleanup: mutex option |
| _port_internal_gateway | 0 | TRUE | IMMEDIATE | port number of Net Listener on Internal Gateway host |
| _post_multiple_shared_waiters | TRUE | FALSE | IMMEDIATE | Post multiple shared waiters of a latch |
| _post_run_job_evaluation | FALSE | FALSE | IMMEDIATE | Control if jobs should evaluate at end of execution |
| _pqq_pdb_load_publish_threshold | 0 | FALSE | IMMEDIATE | difference in percentage controlling PDB load publish |
| _preformat_tempfile_bmbs | TRUE | TRUE | IMMEDIATE | Enable preformatting enough bmbs for tempfile |
| _prespawn_level | FALSE | FALSE | prespawn level | |
| _prespawn_max_count | 50 | FALSE | IMMEDIATE | prespawn max count |
| _primary_guard_wait_timeout | 120 | FALSE | IMMEDIATE | Number of secords for guard wait timeout on primary |
| _process_max_pred_increase | 20000 | FALSE | IMMEDIATE | process SO max predicted increase |
| _process_percent_rampup_end | 10000 | FALSE | FALSE | process SO percent rampup end |
| _process_percent_rampup_start | 1000 | FALSE | FALSE | process SO percent rampup start |
| _process_prediction_failover_buffer | 1 | FALSE | IMMEDIATE | process prediction failover buffer |
| _process_save_prediction | FALSE | FALSE | IMMEDIATE | save process prediction for next instance startup |
| _process_so_max_inc | 20000 | FALSE | IMMEDIATE | process SO max inc |
| _profile_sensitive_users | FALSE | IMMEDIATE | Database Users with restricted password profile | |
| _protect_pga_extents | FALSE | FALSE | FALSE | protection for pga extents |
| _psdclog_enable | FALSE | TRUE | IMMEDIATE | Mandatory Cloud Logging of PL/SQL Utility Packages Usages |
| _psdclog_threshold | 10 | TRUE | IMMEDIATE | Threshold for Cloud Logging of PL/SQL Utility Packages Usages |
| _pseudo_redo_dump | FALSE | FALSE | IMMEDIATE | Convert all internal redo dump to pseudo redo dump |
| _psr_opt | enable feature | FALSE | IMMEDIATE | options for standby pdb recovery |
| _px_adaptive_dist_nij_enabled | on | TRUE | IMMEDIATE | enable adaptive distribution methods for left non-inner joins |
| _px_extended_join_skew_handling | TRUE | TRUE | IMMEDIATE | enables extended skew handling for parallel joins |
| _px_oneslave_per_instance_parse | TRUE | TRUE | IMMEDIATE | send parse to one slave per instance |
| _px_parallelize_non_native_datatype | TRUE | TRUE | IMMEDIATE | enable parallelization for non-native datatypes |
| _px_partition_load_skew_handling | on | TRUE | IMMEDIATE | enable partition load skew handling |
| _px_partition_load_skew_threshold | 3 | TRUE | IMMEDIATE | partition loads bigger than threshold times average are skewed |
| _px_proactive_slave_release | 1 | TRUE | IMMEDIATE | early release of producer slaves of final DFO |
| _px_window_skew_handling | TRUE | TRUE | IMMEDIATE | enable window function skew handling |
| _px_window_skew_sample_size | 1000 | TRUE | IMMEDIATE | window function skew sample size |
| _qesma_access_count | 1 | TRUE | IMMEDIATE | controls scan count collection for X$QESMA_ACCESS_COUNT table |
| _qesma_mvob_pin_lru_sz | 5 | TRUE | IMMEDIATE | size of MVOB pin LRU list for QESMA session cache |
| _qesma_rt_parallel_check | 1 | TRUE | IMMEDIATE | verify qesma metadata at runtime for parallel execution |
| _qkgl_crit_pct_threshold | 80 | FALSE | IMMEDIATE | Queue KGL critical percentage allocation threshold |
| _qkslvc_diag_flags | 0 | TRUE | IMMEDIATE | diagnostic flags for qkslvc |
| _quantified_path_pattern_maximum_upper_bound | 10 | TRUE | IMMEDIATE | maximum upper bound allowed for SQL PGQ quantified path pattern |
| _rce_dblink_hostname_transform | FALSE | TRUE | IMMEDIATE | Transform RCE database link to add hostname |
| _rce_dns_suffix | TRUE | IMMEDIATE | suffix for RCE DNS Proxy based DNS resolution | |
| _rdbms_min_compatibility | 11.2.0.2 | TRUE | IMMEDIATE | default mininum RDBMS compatibility level |
| _rds_congestion_timeout | 0 | FALSE | FALSE | Configure RDS Congestion timer (us) |
| _rds_congestion_type | FALSE | FALSE | Configure RDS Congestion type | |
| _reco_populate_mode | 1 | FALSE | IMMEDIATE | Mode of RECO protocol execution |
| _recycle_con_cache_size | 5 | FALSE | IMMEDIATE | Recycle con# cache size |
| _redo_generation_max_kbytes_sec | 0 | FALSE | IMMEDIATE | redo generation maximum KB/s |
| _redo_indexes_apply | DISABLE | TRUE | IMMEDIATE | utilize redo range indexes in recovery |
| _refclone_redirect | FALSE | FALSE | IMMEDIATE | statement redirection in Refreshable Clone |
| _refclone_source_connect_string | FALSE | IMMEDIATE | connect string for redirection in refreshable clone | |
| _remote_extproc_agent | FALSE | FALSE | FALSE | enable/disable remote extproc agent |
| _remote_http_port | 0 | FALSE | IMMEDIATE | HTTP port number registered with remote listener |
| _remote_sv_sequence | 1 | FALSE | IMMEDIATE | enable smart sv work on remote instances. |
| _remove_hostname_from_module | FALSE | TRUE | IMMEDIATE | If enabled then remove hostname, set only application as module |
| _request_deferral_enabled | FALSE | FALSE | FALSE | enable request deferral |
| _reset_increase_lmd_process | TRUE | FALSE | IMMEDIATE | set to true to allow reset of _increase_lmd_process changes |
| _reset_increase_lms_process | TRUE | FALSE | IMMEDIATE | set to true to allow reset of _increase_lms_process changes |
| _resource_exhaustion_warning_thresholds | 655361281 | TRUE | IMMEDIATE | thresholds and frequency of actions related to resource exhaustion |
| _resource_exhaustion_warnings | 0 | TRUE | IMMEDIATE | enable warnings/crash when certain finite resources are used up |
| _restore_delayed_write | FALSE | TRUE | IMMEDIATE | restore datafiles with delayed write option |
| _result_cache_auto_blocklist_epsilon | 10000 | FALSE | IMMEDIATE | How much better blocklisted objects must be to be unblocklisted |
| _result_cache_auto_blocklist_frequency | 40000 | FALSE | IMMEDIATE | Frequency of autoblocklist checks in units of RC invalidations |
| _result_cache_auto_blocklist_threshold | 1000 | FALSE | IMMEDIATE | Threshold of ratio of ROs created to used before blocklisting |
| _result_cache_auto_broadcast_threshold | 10000 | FALSE | IMMEDIATE | Threshold of RAC round trip times before blocklisting |
| _result_cache_auto_ignore_list | 0 | FALSE | IMMEDIATE | object numbers that will never be auto blocklisted |
| _result_cache_determ_salt | FALSE | FALSE | IMMEDIATE | Use deterministic salt for result cache? |
| _result_cache_do_recycle_period | 300 | FALSE | IMMEDIATE | Timeout value for DOs added through invalidation |
| _result_cache_global_send | TRUE | FALSE | IMMEDIATE | Is global send conditional in RAC? |
| _result_cache_history_size | 0 | FALSE | IMMEDIATE | memory used to track PL/SQL function history |
| _result_cache_latch_count | 0 | FALSE | FALSE | number of result cache latches |
| _result_cache_load_rate | 1 | FALSE | IMMEDIATE | Simulated global load rate (bytes per 1/100 sec) |
| _result_cache_object_black_list | 0 | FALSE | IMMEDIATE | object numbers not allowed to use the result cache |
| _result_cache_use_hash_table | TRUE | FALSE | IMMEDIATE | whether to use hash table for object tracking |
| _retry_file_copy | TRUE | TRUE | IMMEDIATE | Enable retry for file copy in Create PDB |
| _reuse_object_number_delay | 0 | FALSE | IMMEDIATE | delay in days before reusing object numbers |
| _reuse_object_numbers | 5 | FALSE | IMMEDIATE | reuse object numbers |
| _reuse_object_numbers_qa | 0 | FALSE | IMMEDIATE | reuse object numbers testing |
| _rm_cell_cpu_scale | 0 | FALSE | IMMEDIATE | Scaling factor for storage cell cpu usage |
| _rm_exadata_disable_dbcpurm | FALSE | FALSE | IMMEDIATE | Disable the Exadata DB cpu resource manager feature |
| _rm_exadata_fcsize_unit | 0 | FALSE | IMMEDIATE | PDB usage size unit for flash cache for Exadata |
| _rm_exadata_pdb_mult_storage | 1 | FALSE | IMMEDIATE | Multiplier of PDB storage count for Exadata throughput-based IORM limit |
| _rm_sgllim | 0 | FALSE | IMMEDIATE | Single CPU limit control |
| _rm_tolerance_lwt | 5 | FALSE | FALSE | RM tolerance for LWT to report consumed cpu |
| _rolling_vsnnum | FALSE | IMMEDIATE | Mimic given vsnnum during test | |
| _root_clone_skip_trigger | TRUE | TRUE | IMMEDIATE | Skip trigger in Application Root Clone |
| _router_pdb | FALSE | FALSE | IMMEDIATE | enable router PDB functionality |
| _rowsets_use_work_heap_buffer | TRUE | TRUE | IMMEDIATE | allow/disallow use of work heap buffer for values for rowsets |
| _rsrc_cpu_count | FALSE | IMMEDIATE | CPU Count for allocating resources. | |
| _runtime_index_key_length_check | 1 | TRUE | IMMEDIATE | allow runtime checking of index key length |
| _runtime_limit_parallel_fptr | 60 | FALSE | IMMEDIATE | run-time limit for for parallel first-pass recovery |
_s以降から始まる隠しパラメータは次回。
前回の記事：Oracle19cと23cの隠しパラメータの差分について調べてみた ～その4～
