Dictionary and Library Cache
Statistics
The next AWRRPTreport
section deals with dictionary and library cache statistics. An
item to watch for in a RAC environment is excessive sequence
activity as this can indicate that the sequences are not properly
configured for a RAC environment. For example, to be RAC Safe, a
sequence should be cached,
nocycleand
noorder
. The following listing shows
the dictionary and library reports:
Dictionary
Cache Stats DB/Inst: SSD/ssd2 Snaps: 3-4
-> "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 62 3.2 0
0 1
dc_global_oids 1,137 0.0 0
0 22
dc_histogram_defs 110 0.0 0
0 2,285
dc_object_ids 1,507 0.3 0
0 558
dc_objects
436 5.0 0 0 621
dc_profiles
85 0.0 0 0 1
dc_rollback_segments 17,403 0.1 0
30 98
dc_segments 175 8.6 0
41 369
dc_sequences 14 35.7 0
14 6
dc_tablespace_quotas 2 0.0 0
2 1
dc_tablespaces 5,004 0.0 0
0 7
dc_usernames
298 0.0 0 0 11
dc_users
8,822 0.0 0 0 38
outstanding_alerts 36 66.7 0
0 5
-------------------------------------------------------------
Dictionary
Cache Stats (RAC) DB/Inst: SSD/ssd2 Snaps: 3-4
GES GES GES
Cache Requests Conflicts Releases
------------------------- ------------ ------------ ------------
dc_awr_control 2 2 0
dc_object_ids 5 0 0
dc_objects
22 0 0
dc_rollback_segments 57 1 0
dc_segments 84 4 0
dc_sequences 24 4 0
dc_tablespace_quotas 4 0 0
outstanding_alerts 72 24 0
-------------------------------------------------------------
Library
Cache Activity DB/Inst: SSD/ssd2 Snaps: 3-4
-> "Pct
Misses" should be very low
Get Pct
Pin Pct Invali-
Namespace
Requests Miss Requests Miss Reloads dations
--------------- ------------ ------ -------------- ------
---------- --------
BODY 12 0.0 30 0.0
0 0
INDEX 1 0.0 1 0.0
0 0
SQL
AREA 3,111 0.1 77,182 0.0
2 0
TABLE/PROCEDURE 51 0.0 8,823 0.0
0 0
-------------------------------------------------------------
Library
Cache Activity (RAC) DB/Inst: SSD/ssd2 Snaps: 3-4
GES Lock GES Pin GES Pin GES Inval
GES Invali-
Namespace Requests Requests Releases
Requests dations
--------------- ------------ ------------ ------------ -----------
-----------
INDEX 1 0 0
0 0
TABLE/PROCEDURE 309 0 0
0 0
-------------------------------------------------------------
There is a section for the above referenced
section of the AWRRPT that is only present if the database is RAC
enabled. This section shows the dictionary statistics for the
dictionary cache for the global enqueue service
as well as a library cache activity section for GES. As long
as reloads and invalidations are kept to near zero, things are
probably ok. The miss percent of 35% for
dc_sequences probably
indicates some of the instance sequences are not RAC safe.
