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High value for latch free

From: <Ranko.Mosic_at_gmail.com>
Date: 1 Dec 2005 06:59:48 -0800
Message-ID: <1133449188.473523.111050@g47g2000cwa.googlegroups.com>


Top 5

Event			Waits		Time (s)	% Total Elapsed Time
latch free		6,788,898	334,102		69.52
CPU time				145,702		30.32
library cache lock	15,458		197		0.04
db file scattered read	26,956		177		0.04
global cache cr request	61,197		108		0.02



Latch Name			Get Requests	Pct Get Miss
Consistent RBA			13,199		0
FOB s.o list latch		261		0
KCL bast context freelis	138		0
KCL freelist parent latc	428,168		0
KCL gc element parent la	656,067		0
KCL name table parent la	170,406		0
KJC message pool free li	71,181		0
KJCT flow control latch		415,905		0
SQL memory manager latch	8		0
SQL memory manager worka	243,262		0
active checkpoint queue		25,236		0.3
archive control			276		0
archive process latch		144		0
cache buffer handles		161,151		0
cache buffers chains		##############	2.6
cache buffers lru chain		53,782		0
channel handle pool latc	782		0
channel operations paren	39,149		0
checkpoint queue latch		1,436,733	0
child cursor hash table		339		0
dml lock allocation		4,997,532	0.7
dummy allocation		796		0
enqueue hash chains		10,101,506	0
enqueues			99,003		0
event group latch		409		0
gcs resource hash		295,465		0.1
ges caches resource list	3,015,698	0
ges deadlock list		58,009		0
ges domain table		5,036,448	0
ges enqueue table freeli	5,136,422	0
ges group parent		5,037,012	0.1
ges group table			5,037,433	0
ges process hash list		17,100		0
ges process parent latch	17,961,512	0
ges process table freeli	780		0.1
ges resource hash list		7,735,581	0
ges resource scan list		2		0
ges resource table freel	2,460,314	0
ges timeout list		330		0
hash table column usage		23		0
job workq parent latch		0
job_queue_processes para	127		0
ksxp tid allocation		143,467		0
ktm global data			27		0
lgwr LWN SCN			13,382		0
library cache			6,663,181	0.6
library cache pin		4,713,855	0.2
library cache pin alloca	399,042		0
list of block allocation	476		0
loader state object free	3		0
longop free list parent		217		0
message pool operations		2		0
messages			221,805		0
mostly latch-free SCN		13,834		0.6
multiblock read objects		78,444		0
name-service memory obje	18,702		0
name-service namespace b	60,145		0
name-service pending que	8,120		0
name-service request que	59,983		0
ncodef allocation latch		1,746		0
post/wait queue			3,193		0
process allocation		51,203		0
process group creation		780		0
redo allocation			81,306		0
redo copy			0
redo writing			69,845		0
row cache enqueue latch		2,020,106	0.2
row cache objects		2,026,926	0.6
sequence cache			40,110		0
session allocation		118,704		0
session idle bit		1,152,181	0
session switching		1,746		0
session timer			4,072		0
shared pool			2,397,082	0.1
simulator hash latch		802,694,122	0
simulator lru latch		117,084		98.7
sort extent pool		2,276		0
transaction allocation		421		0
transaction branch alloc	1,746		0
undo global data		54,974		0

  1. how is it possible latch free has such a high value for wait time and elapsed time ?
  2. if you add up wait times in latch breakdown table you come nowhere near the figure of 334,102 s in top 5 events
  3. what is the problem here ? ( I also have enqueue showing up in other top 5 reports )

Regards, Ranko. Received on Thu Dec 01 2005 - 08:59:48 CST

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