【Oracle 12c】In-Memory Database Cache内存数据库选项

NAME AVALUE SDESC _inmemory_check_prot_meta FALSE If true, marks SMU area read only to prevent stray writes _inmemory_private_journal_quota 100 quota for transaction in-memory private journals _inmemory_private_journal_sharedpool_quota 20

NAME	AVALUE	SDESC
_inmemory_check_prot_meta	FALSE	If true, marks SMU area read only to prevent stray writes
_inmemory_private_journal_quota	100	quota for transaction in-memory private journals
_inmemory_private_journal_sharedpool_quota	20	quota for transaction in-memory objects
_inmemory_private_journal_numbkts	512	Number of priv jrnl ht bkts
_inmemory_private_journal_numgran	128	Number of granules per HT node
_inmemory_jscan	0	inmemory jscan enable
_inmemory_pin_hist_mode	16	settings for IM pinned buffer history
_inmemory_txn_checksum	0	checksum for SMUs and private journals
_inmemory_buffer_waittime	100	wait interval for one SMU or IMCU to be freed
_inmemory_cu_timeout	100	maximum wait time for one IMCU to be freed
_inmemory_cudrop_timeout	1000	maximum wait time for IMCU to be freed during drop
_inmemory_exclto_timeout	1000	maximum wait time to pin SMU for cleanout
_inmemory_num_hash_latches	256	Maximum number of latches for IM buffers
_inmemory_strdlxid_timeout	0	max time to determine straddling transactions
_inmemory_incremental_repopulation	FALSE	If true, incremental repopulation of IMCU will be attempted
_inmemory_lock_for_smucreate	FALSE	take object lock during smu creation
_inmemory_auto_distribute	TRUE	If true, enable auto distribute
_inmemory_autodist_2safe	FALSE	If true, enable auto distribute with 2safe
_inmemory_distribute_timeout	300	If true, enable auto distribute with 2safe
_inmemory_distribute_ondemand_timeout	300	On demand timeout for redistribute
inmemory_size	0	size in bytes of in-memory area
_inmemory_64k_percent	30	percentage of in-memory area for 64k pools
_inmemory_min_ima_defersize	0	Defer in-memory area allocation beyond this size
_inmemory_memprot	TRUE	enable or disable memory protection for in-memory
_inmemory_analyzer_optimize_for	0	inmemory analyzer optimize for
_inmemory_default_flags	8459	Default flags based on inmemory_clause_default
_inmemory_default_new	FALSE	Force in-memory on new tables
inmemory_clause_default	Default in-memory clause for new tables
inmemory_force	DEFAULT	Force tables to be in-memory or not
inmemory_query	ENABLE	Specifies whether in-memory queries are allowed
_inmemory_query_scan	TRUE	In-memory scan enabled
_inmemory_scan_override	FALSE	In-memory scan override
_inmemory_scan_threshold_percent_noscan	50	In-memory scan threshold maximum percent dirty no scan
_inmemory_small_segment_threshold	65536	In-memory small segment threshold (must be larger for in-memory)
_inmemory_query_fetch_by_rowid	FALSE	In-memory fetch-by-rowid enabled
_inmemory_pruning	ON	In-memory pruning
_inmemory_enable_sys	FALSE	enable in-memory on system tablespace with sys user
_inmemory_populate_fg	FALSE	populate in foreground
_inmemory_pga_per_server	536870912	minimum pga needed per inmemory populate server
inmemory_max_populate_servers	0	maximum inmemory populate servers
_inmemory_servers_throttle_pgalim_percent	55	In-memory populate servers throttling pga limit percentage
inmemory_trickle_repopulate_servers_percent	1	inmemory trickle repopulate servers percent
_inmemory_populate_wait	FALSE	wait for population to complete
_inmemory_populate_wait_max	600	maximum wait time in seconds for segment populate
_inmemory_imco_cycle	120	IMCO cycle in seconds (sleep period)
_inmemory_enable_population_verify	1	verify in-memory population
_inmemory_log_level	1	in-memory log level
_inmemory_fs_verify	FALSE	in-memory faststart verify
_inmemory_force_fs	FALSE	in-memory faststart force
_inmemory_force_fs_tbs	SYSAUX	in-memory faststart force tablespace
_inmemory_force_fs_tbs_size	1073741824	in-memory faststart force tablespace size
_inmemory_fs_raise_error	FALSE	in-memory faststart raise error
_inmemory_fs_nodml	FALSE	in-memory faststart assumes no dmls while populating
_inmemory_fs_enable	FALSE	in-memory faststart enable
_inmemory_fs_enable_blk_lvl_inv	TRUE	in-memory faststart enable block level invalidation
_inmemory_fs_blk_inv_blkcnt	in-memory faststart CU invalidation threshold(blocks)
_inmemory_fs_blk_inv_blk_percent	20	in-memory faststart CU invalidation threshold(blocks)
_inmemory_enable_stat_alert	FALSE	dump in-memory stats in alert log file
_inmemory_imcu_align	TRUE	Enforce 8M IMCU alignment
_inmemory_max_populate_retry	3	IM populate maximum number of retry
_inmemory_imcu_target_rows	1048576	IMCU target number of rows
_inmemory_imcu_target_bytes	0	IMCU target size in bytes
_inmemory_imcu_source_extents	0	number of source extents per IMCU
_inmemory_imcu_source_blocks	0	number of source blocks per IMCU
_inmemory_imcu_source_minbytes	1048576	number of minimum source bytes per IMCU
_inmemory_imcu_populate_minbytes	5242880	minimum free space in IMA for populating IMCU
_inmemory_imcu_source_analyze_bytes	134217728	number of source analyze bytes per IMCU
_inmemory_imcu_target_maxrows	8388608	IMCU maximum target number of rows
_inmemory_imcu_source_maxbytes	536870912	IMCU maximum source size in bytes
_inmemory_max_queued_tasks	0	Maximum queued populating tasks on the auxiliary queue
_inmemory_repopulate_threshold_rows	In-memory repopulate threshold number of modified rows
_inmemory_repopulate_threshold_blocks	In-memory repopulate threshold number of modified blocks
_inmemory_pct_inv_rows_invalidate_imcu	50	In-memory percentage invalid rows for IMCU invalidation
_inmemory_pct_inv_blocks_invalidate_imcu	100	In-memory percentage invalid blocks for IMCU invalidation
_inmemory_repopulate_threshold_mintime_factor	5	In-memory repopulate minimum interval (N*timetorepop)
_inmemory_repopulate_threshold_mintime	0	In-memory repopulate minimum interval (millisec)
_inmemory_repopulate_threshold_scans	0	In-memory repopulate threshold number of scans
_inmemory_repopulate_priority_scale_factor	100	In-memory repopulate priority threshold scale factor
_inmemory_repopulate_invalidate_rate_percent	100	In-memory repopulate invalidate rate percent
_inmemory_repopulate_priority_threshold_row	20	In-memory repopulate priority threshold row
_inmemory_repopulate_priority_threshold_block	40	In-memory repopulate priority threshold block
_inmemory_repopulate_threshold_rows_percent	5	In-memory repopulate threshold rows invalid percentage
_inmemory_repopulate_threshold_blocks_percent	10	In-memory repopulate threshold blocks invalid percentage
_inmemory_repopulate_disable	FALSE	disable In-memory repopulate
_inmemory_check_protect	FALSE	If true, marks in-memory area read only to prevent stray writes
_inmemory_checksum	FALSE	If true, checksums in-memory area to detect stray writes
_inmemory_validate_fetch	FALSE	If true, validate single-row fetch between in-memory and disk
_inmemory_journal_row_logging	FALSE	If true, log the entire row into the in-memory journal
_inmemory_journal_check	0	Depending on value does one of the DML verifications
_inmemory_rows_check_interrupt	1000	Number of rows buffered before interrupt check
_inmemory_dbg_scan	0	In-memory scan debugging
_inmemory_segment_populate_verify	0	In-memory segment populate verification
_inmemory_query_check	0	In-memory query checking
_inmemory_test_verification	0	In-memory verification testing
_inmemory_invalidate_cursors	TRUE	In-memory populate enable cursor invalidations
_inmemory_prepopulate_fg	0	Force prepopulate of in-memory segment in foreground
_inmemory_prepopulate	TRUE	Enable inmemory populate by IMCO
_inmemory_trickle_repopulate	TRUE	Enable inmemory trickle repopulate
_inmemory_trickle_repopulate_threshold_dirty_ratio	0	IMCO Trickle Repopulate threshold dirty ratio
_inmemory_trickle_repopulate_min_interval	300	IMCO Trickle Repopulate Interval
_inmemory_trickle_repopulate_fg	0	Trickle Repopulate in the Foreground
_inmemory_force_non_engineered	FALSE	force non-engineered systems in-memory behavior on RAC
_inmemory_suppress_vsga_ima	FALSE	Suppress inmemory area in v$sga
optimizer_inmemory_aware	TRUE	optimizer in-memory columnar awareness
_optimizer_inmemory_table_expansion	TRUE	optimizer in-memory awareness for table expansion
_optimizer_inmemory_gen_pushable_preds	TRUE	optimizer generate pushable predicates for in-memory
_optimizer_inmemory_autodop	TRUE	optimizer autoDOP costing for in-memory
_optimizer_inmemory_access_path	TRUE	optimizer access path costing for in-memory
_optimizer_inmemory_quotient	0	in-memory quotient (% of rows in in-memory format)
_optimizer_inmemory_pruning_ratio_rows	100	in-memory pruning ratio for # rows (% of rows remaining after pruning)
_parallel_inmemory_min_time_threshold	AUTO	threshold above which a plan is a candidate for parallelization for in-memory tables (in seconds)
_parallel_inmemory_time_unit	1	unit of work used to derive the degree of parallelism for in-memory tables (in seconds)
_optimizer_inmemory_bloom_filter	TRUE	controls serial bloom filter for in-memory tables
_optimizer_inmemory_cluster_aware_dop	TRUE	Affinitize DOP for inmemory objects
_optimizer_inmemory_minmax_pruning	TRUE	controls use of min/max pruning for costing in-memory tables

test

In-Memory Database Cache
  IM                           in-memory ((null))
    IM_transaction             IM transaction layer ((null))
      IM_Txn_PJ                IM Txn Private Journal (ktmpj)
      IM_Txn_SJ                IM Txn Shared Journal (ktmsj)
      IM_Txn_JS                IM Txn Journal Scan (ktmjs)
      IM_Txn_Conc              IM Txn Concurrency (ktmc)
      IM_Txn_Blk               IM Txn Block (ktmb)
      IM_Txn_Read              IM Txn Read (ktmr)
    IM_space                   IM space layer ((null))
    IM_data                    IM data layer (kdm)
      IM_populate              IM populating (kdml)
      IM_background            IM background (kdmr)
      IM_scan                  IM scans ((null))
      IM_journal               IM journal ((null))
      IM_dump                  IM dump ((null))
      IM_FS                    IM faststart ((null))
      IM_optimizer             IM optimizer (kdmo)
	  alter session set events 'trace[IM_scan] disk=medium';
	  SQL> alter system set inmemory_size=2g scope=spfile;
System altered.
SQL> shutdown immediate;
[oracle@mlab2 ~]$ sqlplus  / as sysdba
SQL*Plus: Release 12.1.0.2.0 Production on Wed Sep 3 23:18:18 2014
Copyright (c) 1982, 2014, Oracle.  All rights reserved.
Connected to an idle instance.
SQL> startup;
ORACLE instance started.
Total System Global Area 2684354560 bytes
Fixed Size                  2928008 bytes
Variable Size             402653816 bytes
Database Buffers          117440512 bytes
Redo Buffers               13848576 bytes
In-Memory Area           2147483648 bytes
Database mounted.
Database opened.
    alter session set events 'trace[IM_scan] disk=medium';
      select count(*) from mac_imm1;
	SQL> oradebug setmypid
Statement processed.
SQL> oradebug tracefile_name
/s01/diag/rdbms/c12r1/C12R1/trace/C12R1_ora_16700.trc
kdmsirs(): map with 13 extents
Ext: 0, dba: 0x18000db, len: 5, skp: 0
Ext: 1, dba: 0x18000e0, len: 8, skp: 0
Ext: 2, dba: 0x18000e9, len: 7, skp: 0
Ext: 3, dba: 0x18000f0, len: 8, skp: 0
Ext: 4, dba: 0x18000f9, len: 7, skp: 0
Ext: 5, dba: 0x1800100, len: 8, skp: 0
Ext: 6, dba: 0x1800109, len: 7, skp: 0
Ext: 7, dba: 0x1800110, len: 8, skp: 0
Ext: 8, dba: 0x1800119, len: 7, skp: 0
Ext: 9, dba: 0x1800120, len: 8, skp: 0
Ext: 10, dba: 0x1800129, len: 7, skp: 0
Ext: 11, dba: 0x1800130, len: 8, skp: 0
Ext: 12, dba: 0x1800139, len: 1, skp: 0 
kdmsStartEndDBA(): scan start: 0x18000db end: 0x18000df rdba[0]: 0x18000db size[0]: 5, nblks: 5  extno: 0, skip: 0
kdmsGetIMCU(): In arguments: nblks 5: start_addr 25166043, end_addr 25166047
kdmsGetIMCU(): Mem addr: baffffd0: mem len: 1048576: Start dba: 0x18000db 25166043: len: 5 smu: fbf44770 td: 0x7f76515361a8
kdmsGetIMCU(): range: 0 lrid dba: 0x0 slot: 0 hrid dba: 0x0 slot: 0
kdmsGetIMCU(): found imcu 0xbaffffd0 25166043 25166047 1
kdst_fetch_imc(): imcu get 0x18000db
kdmsTransGet(): got ktmrds for dba 0x18000db, td : 0x7f76515361a8
kdmsFindEndDba: ext in imcu is 0, and on disk 0
IMCU extents
extent 0: 25166043 0x18000db + 5
extent 1: 25166048 0x18000e0 + 8
extent 2: 25166057 0x18000e9 + 7
extent 3: 25166064 0x18000f0 + 8
extent 4: 25166073 0x18000f9 + 7
extent 5: 25166080 0x1800100 + 8
extent 6: 25166089 0x1800109 + 7
extent 7: 25166096 0x1800110 + 8
extent 8: 25166105 0x1800119 + 7
extent 9: 25166112 0x1800120 + 8
extent 10: 25166121 0x1800129 + 7
extent 11: 25166128 0x1800130 + 8
extent 12: 25166137 0x1800139 + 1 
Disk extents
extent 0: 25166043 0x18000db + 5 (skip = 0)
extent 1: 25166048 0x18000e0 + 8 (skip = 0)
extent 2: 25166057 0x18000e9 + 7 (skip = 0)
extent 3: 25166064 0x18000f0 + 8 (skip = 0)
extent 4: 25166073 0x18000f9 + 7 (skip = 0)
extent 5: 25166080 0x1800100 + 8 (skip = 0)
extent 6: 25166089 0x1800109 + 7 (skip = 0)
extent 7: 25166096 0x1800110 + 8 (skip = 0)
extent 8: 25166105 0x1800119 + 7 (skip = 0)
extent 9: 25166112 0x1800120 + 8 (skip = 0)
extent 10: 25166121 0x1800129 + 7 (skip = 0)
extent 11: 25166128 0x1800130 + 8 (skip = 0)
extent 12: 25166137 0x1800139 + 1 (skip = 0)
kdmsFindEndDba(): begin: 25166043, end dba: 25166137     done ext in imcu 12 on disk 12
min of imcu end 25166138 0x180013a disk end 25166138 0x180013a discont 0
kdst_fetch_imc(): done: 1, empty: 0, ftch: 0
kdst_fetch_imc(): fetch: 0, invalid: 0
kdmsRepopulate(): repop 0 nblks 89 0 nrows 2342 0 cnt 5
kdstf00100010001101kmP(): create vv 18000db 95
kdmsCreateIMCUValidVector: Scan range (25166043, 25166137)
Extent map passed into kdzd layer:
Extent 0: (25166043, 25166047)
Extent 1: (25166048, 25166055)
Extent 2: (25166057, 25166063)
Extent 3: (25166064, 25166071)
Extent 4: (25166073, 25166079)
Extent 5: (25166080, 25166087)
Extent 6: (25166089, 25166095)
Extent 7: (25166096, 25166103)
Extent 8: (25166105, 25166111)
Extent 9: (25166112, 25166119)
Extent 10: (25166121, 25166127)
Extent 11: (25166128, 25166135)
Extent 12: (25166137, 25166137)
kdzd_dump_validvec:
IMCU: 1
Num slots: 2342 set: 2342 rounded to 8: 2368 bytes: 296
Flag if all rows valid: 1
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.
ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.3f.
3 final 0
kdzd_dump_validvec: End Dumping Valid Vector
**************** ktmrDS Dump  *****************
pdb=0, tsn=4, rdba=25166043, objn=91999, objd=91999, typ=1, gflg=0 flg=0
loadscn=scn: 0x0000.001af80b
invalid blkcnt=0, fetch blkcnt=0
env [0x7f765152af6c]: (scn: 0x0000.001af830   xid: 0x0000.000.00000000  uba: 0x00000000.0000.00  statement num=0  parent xid:  0x0000.000.00000000  st-scn: 0x0000.00000000  hi-scn: 0x0000.00000000  ma-scn: 0x0000.001af82c  flg: 0x00000660)invalid rowcnt=0,
 fetch rowcnt=0
kdst_fetch_imc(): release 0x18000db from td: 0x7f76515361a8
kdmsGetJournalRows(): done with IMC fetch; journal rows -1
kdmsEnd(): imcuctx 0x7f7651688b78 release 0x18000db from td: 0x7f76515361a8

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原文地址：【Oracle 12c】In-Memory Database Cache内存数据库选项, 感谢原作者分享。