Hidden Parameters in Oracle AI Database 26ai H.10 LOB / compression (98)

 

Name	Type	Value	At default?	Level	PDB	RAC inst.	Flags	Description
_kdli_STOP_bsz	Integer	0	yes	SESSION	Y	N		undocumented parameter for internal use only
_kdli_STOP_dba	Integer	0	yes	SESSION	Y	N		undocumented parameter for internal use only
_kdli_STOP_fsz	Integer	0	yes	SESSION	Y	N		undocumented parameter for internal use only
_kdli_STOP_nio	Integer	0	yes	SESSION	Y	N		undocumented parameter for internal use only
_kdli_STOP_tsn	Integer	0	yes	SESSION	Y	N		undocumented parameter for internal use only
_kdli_adaptive_cache_inode	Boolean	TRUE	yes	SESSION	Y	N		enable adaptive inode cache
_kdli_adpt_sio_mem	Boolean	TRUE	yes	SESSION	Y	N		adaptive sio memory buffer
_kdli_allow_corrupt	Boolean	FALSE	yes	SESSION	Y	N		allow corrupt filesystem_logging data blocks during read/write
_kdli_buffer_inject	Boolean	TRUE	yes	SESSION	Y	N		use buffer injection for CACHE [NO]LOGGING lobs
_kdli_cache_hless_limit	Integer	4	yes	SESSION	Y	N		#of extents to cache headless inode
_kdli_cache_inode	Boolean	TRUE	yes	SESSION	Y	N		cache inode state across calls
_kdli_cache_inode_off_limit	Integer	8192	yes	SESSION	Y	N		cache_off limit for adaptive inode cache
_kdli_cache_read_threshold	Integer	0	yes	SESSION	Y	N		minimum lob size for cache->nocache read (0 disables heuristic)
_kdli_cache_size	Integer	8	yes	SESSION	Y	N		maximum #entries in inode cache
_kdli_cache_verify	Boolean	FALSE	yes	SESSION	Y	N		verify cached inode via deserialization
_kdli_cache_write_threshold	Integer	0	yes	SESSION	Y	N		minimum lob size for cache->nocache write (0 disables heuristic)
_kdli_cacheable_length	Integer	0	yes	SESSION	Y	N		minimum lob length for inode cacheability
_kdli_checkpoint_flush	Boolean	FALSE	yes	SESSION	Y	N		do not invalidate cache buffers after write
_kdli_dbc	String	none	yes	SESSION	Y	N		override db_block_checking setting for securefiles
_kdli_delay_flushes	Boolean	TRUE	yes	SESSION	Y	N		delay flushing cache writes to direct-write lobs
_kdli_descn_adj	Boolean	FALSE	yes	SESSION	Y	N		coalesce extents with deallocation scn adjustment
_kdli_flush_cache_reads	Boolean	FALSE	yes	SESSION	Y	N		flush cache-reads data blocks after load
_kdli_flush_injections	Boolean	TRUE	yes	SESSION	Y	N		flush injected buffers of CACHE NOLOGGING lobs before commit
_kdli_force_cr	Boolean	TRUE	yes	SESSION	Y	N		force CR when reading data blocks of direct-write lobs
_kdli_force_cr_meta	Boolean	TRUE	yes	SESSION	Y	N		force CR when reading metadata blocks of direct-write lobs
_kdli_force_storage	String	none	yes	SESSION	Y	N		force storage settings for all lobs
_kdli_full_readahead_threshold	Integer	0	yes	SESSION	Y	N		maximum lob size for full readahead
_kdli_full_vll	Boolean	FALSE	yes	SESSION	Y	N		materialize full vll lobmap for reads
_kdli_icache_entries	Integer	3	yes	SESSION	Y	N		size of itree cache
_kdli_inject_assert	Integer	0	yes	SESSION	Y	N		inject asserts into the inode
_kdli_inject_batch	Integer	0	yes	SESSION	Y	N		buffer injection batch size [1, KCBNEWMAX]
_kdli_inject_crash	Integer	0	yes	SESSION	Y	N		inject crashes into the inode
_kdli_inline_xfm	Boolean	TRUE	yes	SESSION	Y	N		allow inline transformed lobs
_kdli_inode_preference	String	data	yes	SESSION	Y	N		inline inode evolution preference (data, headless, lhb)
_kdli_inplace_overwrite	Integer	0	yes	SESSION	Y	N		maximum inplace overwrite size (> chunksize)
_kdli_itree_entries	Integer	0	yes	SESSION	Y	N		#entries in lhb/itree blocks (for testing only)
_kdli_memory_protect	Boolean	FALSE	yes	SESSION	Y	N		trace accesses to inode memory outside kdli API functions
_kdli_mts_so	Boolean	TRUE	yes	SESSION	Y	N		use state objects in shared server for asyncIO pipelines
_kdli_oneblk	Boolean	FALSE	yes	SESSION	Y	N		allocate chunks as single blocks
_kdli_preallocation_mode	String	length	yes	SESSION	Y	N		preallocation mode for lob growth
_kdli_preallocation_pct	Integer	0	yes	SESSION	Y	N		percentage preallocation [0 .. inf) for lob growth
_kdli_ralc_length	Integer	10485760	yes	SESSION	Y	N		lob length threshold to trigger rounded allocations
_kdli_ralc_rounding	Integer	1048576	yes	SESSION	Y	N		rounding granularity for rounded allocations
_kdli_rci_lobmap_entries	Integer	255	yes	SESSION	Y	N		#entries in RCI lobmap before migration to lhb
_kdli_readahead_limit	Integer	0	yes	SESSION	Y	N		shared/cached IO readahead limit
_kdli_readahead_strategy	String	contig	yes	SESSION	Y	N		shared/cached IO readahead strategy
_kdli_recent_scn	Boolean	FALSE	yes	SESSION	Y	N		use recent (not dependent) scns for block format/allocation
_kdli_reshape	Boolean	FALSE	yes	SESSION	Y	N		reshape an inode to inline or headless on length truncation
_kdli_rinode_purge	Boolean	TRUE	yes	SESSION	Y	N		enable read inode purge
_kdli_safe_callbacks	Boolean	TRUE	yes	SESSION	Y	N		invoke inode read/write callbacks safely
_kdli_sio_async	Boolean	TRUE	yes	SESSION	Y	N		asynchronous shared IO
_kdli_sio_backoff	Boolean	FALSE	yes	SESSION	Y	N		use exponential backoff when attempting SIOP allocations
_kdli_sio_bps	Integer	0	yes	SESSION	Y	N		maximum blocks per IO slot
_kdli_sio_chkpt	Boolean	TRUE	yes	SESSION	Y	N		Control SIO checkpointing during PQ Direct reads/parallel scans
_kdli_sio_dop	Integer	2	yes	SESSION	Y	N		degree-of-parallelism in the SIO keep pool
_kdli_sio_fbwrite_pct	Integer	35	yes	SESSION	Y	N		percentage of buffer used for direct writes in flashback-db
_kdli_sio_fileopen	String	none	yes	SESSION	Y	N		shared IO fileopen mode: datasync vs nodatasync vs async
_kdli_sio_flush	Boolean	FALSE	yes	SESSION	Y	N		enable shared IO pool operations
_kdli_sio_free	Boolean	TRUE	yes	SESSION	Y	N		free IO buffers when not in active use
_kdli_sio_min_read	Integer	0	yes	SESSION	Y	N		shared IO pool read threshold
_kdli_sio_min_write	Integer	0	yes	SESSION	Y	N		shared IO pool write threshold
_kdli_sio_nbufs	Integer	8	yes	SESSION	Y	N		maximum #IO buffers to allocate per session
_kdli_sio_niods	Integer	8	yes	SESSION	Y	N		maximum #IO descriptors to allocate per session
_kdli_sio_on	Boolean	TRUE	yes	SESSION	Y	N		enable shared IO pool operations
_kdli_sio_pga	Boolean	FALSE	yes	SESSION	Y	N		use PGA allocations for direct IO
_kdli_sio_pga_top	Boolean	FALSE	yes	SESSION	Y	N		PGA allocations come from toplevel PGA heap
_kdli_sio_strategy	String	extent	yes	SESSION	Y	N		shared IO strategy: block vs. extent
_kdli_sio_write_pct	Integer	100	yes	SESSION	Y	N		percentage of buffer used for direct writes
_kdli_small_append_redo	Boolean	TRUE	yes	SESSION	Y	N		detect and use redo optimizations for small appends
_kdli_small_cache_limit	Integer	32	yes	SESSION	Y	N		size limit of small inode cache
_kdli_sort_dbas	Boolean	FALSE	yes	SESSION	Y	N		sort dbas during chunkification
_kdli_space_cache_limit	Integer	2048	yes	SESSION	Y	N		maximum #blocks in per-segment space cache
_kdli_space_cache_segments	Integer	16	yes	SESSION	Y	N		#segments in space cache
_kdli_squeeze	Boolean	TRUE	yes	SESSION	Y	N		compact lobmap extents with contiguous dbas
_kdli_timer_dmp	Boolean	FALSE	yes	SESSION	Y	N		dump inode timers on session termination
_kdli_timer_trc	Boolean	FALSE	yes	SESSION	Y	N		trace inode timers to uts/tracefile
_kdli_trace	Integer	0	yes	SESSION	Y	N		inode trace level
_kdli_vll_direct	Boolean	TRUE	yes	SESSION	Y	N		use skip-navigation and direct-positioning in vll-domain
_kdz_clear_analysis_percent	Integer	60	yes	SESSION	Y	N		percentage to clear dictionary analysis
_kdz_hcc_flags	Integer	0	yes	SESSION	Y	Y		Miscellaneous HCC flags
_kdz_hcc_track_upd_rids	Boolean	FALSE	yes	SESSION	Y	Y		Enable rowid tracking during updates
_kdz_pcode_flags	Integer	0	yes	SESSION	Y	Y		pcode flags
_kdz_pcode_qk_flags	Integer	0	yes	SESSION	Y	Y		pcode query compilation flags
_kdz_pred_nrows	Integer	32767	yes	SESSION	Y	Y		Number of rows to predicate at a time in kdzt
_kdz_proj_nrows	Integer	1024	yes	SESSION	Y	Y		Number of rows to project at a time in kdzt
_kdzado_postdm_mode	Integer	0	yes	SESSION	Y	Y		kdzado post dm action mode
_kdzf_columnar_cache	String	default	yes	SESSION	Y	Y		Enable Columnar Flash Cache String Mode
_kdzh_mhcc_min_aligned_chunk	Integer	0	yes	SESSION	Y	Y		Number of bytes for MHCC min aligned chunk to acquire
_kdzk_enable_init_trace	Boolean	FALSE	yes	SESSION	Y	Y		Enable kdzk initialization tracing
_kdzk_load_specialized_library	Integer	3	yes	SESSION	Y	Y		Flags for loading HPK specialized library
_kdzk_specialized_library_name	String		yes	SESSION	Y	Y		HPK specialized library name
_kdzk_trace_level	Integer	0	yes	SESSION	Y	Y		HPK trace level
_kdzx_enable_init_trace	Boolean	FALSE	yes	SESSION	Y	Y		Enable kdzx initialization tracing
_kdzx_load_specialized_library	Integer	1	yes	SESSION	Y	Y		Flags for loading HPK HWA specialized library
_kdzx_specialized_library_name	String		yes	SESSION	Y	Y		HPK HWA specialized library name
_kdzx_trace_level	Integer	0	yes	SESSION	Y	Y		HPK HWA trace level
_lob_use_locator_varying_width	Boolean	FALSE	yes	SESSION	N	N		use varying width flag in lob locator
_lobfrag_objd_cache	Integer	1	yes	SESSION	Y	Y		controls LOB fragment dataobj# caching