Hello, All!
I'm new to this forum and i'm not sure if i'm able to post questions like this here.
I'm facing the problem with really high concurrences for row cache objects in a database.
Could someone help me to find the reason for it or send me in the right direction in my searching?
Here's the excerpt from AWR for last 3,5 hours:
Top 5 Timed Foreground Events
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Avg
wait % DB
Event Waits Time(s) (ms) time Wait Class
------------------------------ ------------ ----------- ------ ------ ----------
latch: row cache objects 127,452,881 3,058,038 24 80.3 Concurrenc
cursor: pin S wait on X 476,147 271,907 571 7.1 Concurrenc
db file sequential read 22,066,495 233,666 11 6.1 User I/O
DB CPU 193,349 5.1
library cache: mutex X 5,000,294 17,950 4 .5 Concurrenc
Dictionary Cache Stats DB/Inst: --------- Snaps: 26314-26328
-> "Pct Misses" should be very low (< 2% in most cases)
-> "Final Usage" is the number of cache entries being used
Get Pct Scan Pct Mod Final
Cache Requests Miss Reqs Miss Reqs Usage
------------------------- ------------ ------ ------- ----- -------- ----------
dc_awr_control 769 0.0 0 N/A 28 1
dc_files 15,318 39.6 0 N/A 0 666
dc_global_oids 37,214 4.8 0 N/A 0 43
dc_histogram_data 1.537971E+09 0.0 0 N/A 0 21,233
dc_object_grants 143,088 0.9 0 N/A 0 187
dc_objects 143,387,924 0.0 0 N/A 9 6,471
dc_profiles 382,829 0.0 0 N/A 0 1
dc_rollback_segments 1,416,812 0.0 0 N/A 0 10,272
dc_segments 33,731,523 0.1 0 N/A 21 4,126
dc_sequences 907 56.0 0 N/A 907 6
dc_tablespace_quotas 36 47.2 0 N/A 0 2
dc_tablespaces 2,301,889 0.0 0 N/A 0 158
dc_users 61,573,004 0.0 0 N/A 0 268
global database name 391,810 0.0 0 N/A 0 1
outstanding_alerts 3,480 100.0 0 N/A 1 0
-------------------------------------------------------------
The version of database is 11.2.0.2.0
Edited by: user2586601 on Nov 21, 2012 3:53 AM