Hidden Parameters in Oracle AI Database 26ai H.12 Redo / recovery (91)

 

Name	Type	Value	At default?	Level	PDB	RAC inst.	Flags	Description
_lgwr_delay_slave_write	Boolean	FALSE	yes	SYSTEM imm.	N	Y		Enable LGnn write delay for testing
_lgwr_delay_write	Boolean	FALSE	yes	SYSTEM imm.	N	Y		Enable LGWR write delay for testing
_lgwr_delay_write_csec	Integer	300	yes	SYSTEM imm.	N	Y		If LGWR write delays are enabled, delay each write by this amount
_lgwr_delay_write_interval	Integer	20	yes	SYSTEM imm.	N	Y		If LGWR write delays are enabled, delay every Nth write
_lgwr_io_outlier	Integer	0	yes	SYSTEM imm.	N	Y		LGWR I/O outlier frequency
_lgwr_io_slaves	Integer	0	yes	STATIC	N	N		LGWR I/O slaves
_lgwr_max_ns_wt	Integer	1	yes	STATIC	N	N		Maximum wait time for lgwr to allow NetServer to progress
_lgwr_ns_nl_max	Integer	1000	yes	STATIC	N	N		Variable to simulate network latency or buffer threshold
_lgwr_ns_nl_min	Integer	500	yes	STATIC	N	N		Variable to simulate network latency or buffer threshold
_lgwr_ns_sim_err	Integer	0	yes	SYSTEM imm.	N	Y		Variable to simulate errors lgwrns
_lgwr_posts_for_pending_bcasts	Boolean	FALSE	yes	STATIC	N	N		LGWR posts commit waiters for pending broadcasts
_lgwr_ta_sim_err	Integer	0	yes	SYSTEM imm.	N	Y		Variable to simulate errors lgwr true async
_lgwr_thick_mode_config	String	1:2:1536:8192:1500	yes	SYSTEM imm.	N	Y		adaptive overlapped writes thick mode configuration
_lgwr_thin_mode_config	String	1:256:256:100:750	yes	SYSTEM imm.	N	Y		adaptive overlapped writes thin mode configuration
_log_archive_buffers	Integer	10	yes	STATIC	N	N		Number of buffers to allocate for archiving
_log_archive_network_redo_size	Integer	10	yes	SYSTEM imm.	N	Y		Log archive network redo buffer size used by ARCH
_log_archive_prot_auto_demote	Boolean	FALSE	yes	SYSTEM imm.	N	Y		log archive protection auto demotion
_log_archive_strong_auth	Boolean	TRUE	yes	SYSTEM imm.	N	Y		log archive security strong auth
_log_archive_trace_pids	String		yes	SYSTEM imm.	N	Y		log archive trace pids parameter
_log_blocks_during_backup	Boolean	TRUE	yes	STATIC	N	N		log block images when changed during backup
_log_buffer_coalesce	Boolean	FALSE	yes	STATIC	N	N		Coalescing log buffers for log writes
_log_buffers_corrupt	Boolean	FALSE	yes	STATIC	N	N		corrupt redo buffers before write
_log_buffers_debug	Boolean	FALSE	yes	STATIC	N	N		debug redo buffers (slows things down)
_log_checkpoint_recovery_check	Integer	0	yes	STATIC	N	N		# redo blocks to verify after checkpoint
_log_client_ip_address_to_alert	Boolean	FALSE	yes	SYSTEM imm.	Y	Y		Log Client IP Address to alert file for each login
_log_committime_block_cleanout	Boolean	TRUE	yes	SYSTEM imm.	Y	Y		Log commit-time block cleanout
_log_deletion_policy	String	mandatory	yes	SESSION	Y	Y		archivelog deletion policy for mandatory/all destination
_log_file_sync_timeout	Integer	10	yes	SYSTEM imm.	N	Y		Log file sync timeout (centiseconds)
_log_parallelism_dynamic	Boolean	TRUE	yes	STATIC	N	N		Enable dynamic strands
_log_parallelism_max	Integer	2	yes	STATIC	N	N		Maximum number of log buffer strands
_log_private_mul	Integer	5	yes	STATIC	N	N		Private strand multiplier for log space preallocation
_log_private_parallelism_mul	Integer	10	yes	STATIC	N	N		Active sessions multiplier to deduce number of private strands
_log_read_buffer_size	Integer	8	yes	SYSTEM imm.	N	Y		buffer size for reading log files
_log_read_buffers	Integer	8	yes	STATIC	N	N		Number of log read buffers for media recovery
_log_segment_dump_parameter	Boolean	TRUE	yes	SYSTEM imm.	N	Y		Dump KSP on Log Segmentation
_log_segment_dump_patch	Boolean	TRUE	yes	SYSTEM imm.	N	Y		Dump Patchinfo on Log Segmentation
_log_silicon_secured_memory	Boolean	TRUE	yes	STATIC	N	N		enable silicon secured memory (log)
_log_simultaneous_copies	Integer	8	yes	STATIC	N	N		number of simultaneous copies into redo buffer(# of copy latches)
_log_space_errors	Boolean	TRUE	yes	STATIC	N	N		should we report space errors to alert log
_log_switch_timeout	Integer	0	yes	SYSTEM imm.	N	Y		Maximum number of seconds redos in the current log could span
_log_switch_tracing_iterations	Integer	5	yes	SYSTEM imm.	N	Y		no. of iterations to trace after logswitch timeout
_log_switch_tracing_timeout	Integer	200	yes	SYSTEM imm.	N	Y		dbwr to trace after logswitch timeout in secs
_log_write_info_size	Integer	4096	yes	STATIC	N	N		Size of log write info array
_log_write_worker_post_spinwait	Integer	0	yes	STATIC	N	N		How long log write workers spin wait before posting FGs
_log_write_worker_task_prefetch	String	EARLY	yes	STATIC	N	N		Log write worker prefetches tasks
_log_write_worker_task_spinwait	Integer	0	yes	STATIC	N	N		How long log write workers spin wait for imminent tasks
_log_writer_worker_dlm_hearbeat_update_freq	Integer	5000	yes	SYSTEM imm.	N	Y		LGWR worker DLM health-monitoring heartbeat update frequency (ms)
_logminer_parallel_read	Boolean	TRUE	yes	SYSTEM imm.	N	N		LogMiner parallel read
_logout_storm_rate	Integer	0	yes	SYSTEM imm.	N	Y		number of processes that can logout in a second
_logout_storm_retrycnt	Integer	600	yes	SYSTEM imm.	N	Y		maximum retry count for logouts
_logout_storm_timeout	Integer	5	yes	SYSTEM imm.	N	Y		timeout in centi-seconds for time to wait between retries
_recovery_asserts	Boolean	FALSE	yes	STATIC	N	N		if TRUE, enable expensive integrity checks
_recovery_percentage	Integer	50	yes	SYSTEM imm.	N	Y		recovery buffer cache percentage
_recovery_read_limit	Integer	1024	yes	SYSTEM imm.	N	Y		number of recovery reads which can be outstanding
_recovery_skip_cfseq_check	Boolean	FALSE	yes	SYSTEM imm.	N	Y		allow media recovery even if controlfile seq check fails
_recovery_test_kdivs	Integer	0	yes	SESSION	N	N		If not 0, Throw error in kdivs_hnsw_scan_get_rids
_recovery_verify_writes	Boolean	FALSE	yes	SYSTEM imm.	N	Y		enable thread recovery write verify
_redo_compatibility_check	Boolean	FALSE	yes	STATIC	N	N		general and redo/undo compatibility sanity check
_redo_encryption_cipher_mode	String	XTS	yes	SYSTEM imm.	Y	Y		default redo encryption block cipher mode
_redo_generation_max_kbytes_sec	Integer	0	yes	SYSTEM imm.	Y	Y		redo generation maximum KB/s (hidden parameter)
_redo_indexes_apply	String	DISABLE	yes	SESSION	Y	Y		utilize redo range indexes in recovery
_redo_log_check_backup	Integer	10	yes	SYSTEM imm.	N	Y		time interval in minutes between wakeups to check backup of redo logs
_redo_log_debug_config	Integer	0	yes	SYSTEM imm.	N	Y		Various configuration flags for debugging redo logs
_redo_log_key_reuse_count	Integer	0	yes	SYSTEM imm.	N	Y		Determines the number of redo logs sharing the same redo log key
_redo_log_record_life	Integer	168	yes	SYSTEM imm.	N	Y		Life time in hours for redo log table records
_redo_read_from_memory	Boolean	TRUE	yes	STATIC	N	N		Enable reading redo from in-memory log buffer
_redo_throttle_call_secs_threshold	Integer	10	yes	SYSTEM imm.	N	Y		redo throttle call time threshold (seconds)
_redo_throttle_log_buffer_active_threshold	Integer	30	yes	SYSTEM imm.	N	Y		redo throttle log buffer available active threshold (percent)
_redo_throttle_log_buffer_continue_threshold	Integer	60	yes	SYSTEM imm.	N	Y		redo throttle log buffer available continue threshold (percent)
_redo_throttle_max_jitter	Integer	10000	yes	SYSTEM imm.	N	Y		redo throttle maximum jitter (usec)
_redo_throttle_min_sleep_csec	Integer	10	yes	SYSTEM imm.	N	Y		redo throttle minimum sleep (csec)
_redo_throttle_redo_size_min	Integer	10485760	yes	SYSTEM imm.	N	Y		redo throttle redo size minimum (bytes)
_redo_throttle_redo_size_percentile	Integer	70	yes	SYSTEM imm.	N	Y		redo throttle redo size percentile
_redo_throttle_redo_size_retention	Integer	3600	yes	STATIC	N	N		redo throttle redo size data retention secs
_redo_throttle_redo_size_threshold	Integer	200	yes	SYSTEM imm.	N	Y		redo throttle redo size threshold (percent of mean)
_redo_transport_async_mode	Integer	0	yes	STATIC	N	N		redo transport ASYNC process mode
_redo_transport_compress_all	Boolean	TRUE	yes	STATIC	N	N		Is ASYNC LNS compression allowed?
_redo_transport_evict_threshold	Integer	10	yes	SYSTEM imm.	N	Y		Threshold beyond which a slower ASYNC connection will be evicted
_redo_transport_max_kbytes_sec	Integer	0	yes	SYSTEM imm.	N	Y		redo transport maximum KB/s
_redo_transport_min_kbytes_sec	Integer	0	yes	SYSTEM imm.	N	Y		redo transport minimum KB/s
_redo_transport_redo_log_management	String		yes	SYSTEM imm.	N	Y		redo log management
_redo_transport_resource_management	Boolean	FALSE	yes	SYSTEM imm.	N	Y		Redo transport resource management
_redo_transport_sanity_check	Integer	0	yes	SYSTEM imm.	N	Y		redo transport sanity check bit mask
_redo_transport_stall_time	Integer	360	yes	SYSTEM imm.	N	Y		use parameter DATA_GUARD_MAX_IO_TIME
_redo_transport_stall_time_long	Integer	3600	yes	SYSTEM imm.	N	Y		use parameter DATA_GUARD_MAX_LONGIO_TIME
_redo_transport_stream_test	Boolean	TRUE	yes	STATIC	N	N		test stream connection?
_redo_transport_stream_writes	Boolean	TRUE	yes	STATIC	N	N		Stream network writes?
_redo_transport_vio_size_req	Integer	1048576	yes	STATIC	N	N		VIO size requirement
_redo_write_coalesce_all_threshold	Integer	0	yes	STATIC	N	N		Redo write coalescing threshold (all strands) in bytes
_redo_write_coalesce_slave_threshold	Integer	0	yes	STATIC	N	N		Redo write coalescing threshold (slave strands) in bytes
_redo_write_sync_single_io	Boolean	TRUE	yes	STATIC	N	N		enable sync I/O for single redo write