Part IV in our series will focus on determining which internal
Oracle views hold the information to our enabled statistical gathering.
-
In Part I, we
learned how to set the CLIENT_IDENTIFIER session variable to more accurately
pinpoint resource consumption for an individual user or group of users. -
In Part
II, we learned how to set the ACTION and MODULE name so that we could track
where in our code transactions were being executed and track the use of resources
by transaction type or section of code. -
In Part
III, we focused on enabling tracing of statistics through the DBMS_MONITOR
package. -
Now in part IV of this series we will look at the internal views
within Oracle that keep track of the enabled statistics gathering enabled in
Part III.
In Part III, we left off displaying the enabled traces and
statistic gatherings we enabled through the DBMS_MONITOR package. Recall that
in Part III we queried the DBA_ENABLED_AGGREGATIONS view and had a listing such
as in Listing 1. Table 1 gives a breakdown of the
DBA_ENABLED_AGGREGATIONS view as I have renamed some of the columns for Listing
1.
Listing 1
DBA_ENABLED_AGGREGATIONS
SQL> SELECT * FROM DBA_ENABLED_AGGREGATIONS ;AGGREGATION SERVICE MODULE ACTION
——————– ——————– ——————– ——————–
CLIENT_ID webclient
SERVICE_MODULE ACCT PAYROLL
Table 1
DBA_ENABLED_AGGREGATIONS
Column |
Description |
AGGREGATION_TYPE |
This |
PRIMARY_ID |
This is the CLIENT_IDENTIFIER or SERVICE_NAME in the call |
QUALIFIER_ID1 |
The module name |
QUALIFIER_ID2 |
The action name |
In the last three parts of this series, we have also zeroed
in on setting different session environment variables. Those variables were
CLIENT_IDENTIFIER, ACTION, and MODULE. We have also tracked some of the
sessions by SID, SESSION_ID, SERVICE_NAME, and SERIAL#. I thought it might be
interesting to look at where within Oracle’s internal views these columns might
be defined since this could help us in future needs of our investigation.
Instead of searching through the endless documentation of Oracle, I instead
decided to produce a query (Listing 2) in which I queried the
DBA_TAB_COLUMNS view to look at what internal Oracle views or objects have
these columns in common. From the output, I can then look at the definitions of
those named objects that intrigue me. Listing 2 is only a partial
listing and I encourage you to execute the query and see the total output. That
way if you are ever interested in searching for a single column or combination
of columns you will know where within the Oracle internal views this
information is stored. Do not take this output too lightly. If you remember
that we were enabling statistics gathering and tracing in the previous parts to
this article for combinations of these columns, you can quickly see where in
this listing the information is kept and where aggregates on columns are
stored. Also, be warned that most of the output you will see are for Oracle’s
workload repository, advisories, and snapshots mechanisms and are not of any
real use unless you are using those utilities. For us I have only left the
objects we will be concerned with for looking at the gathered statistics we
have enabled. Table 2 gives a brief explanation of these views, how you might
use them, and some things to look out for.
Listing 2
Query to investigate Oracle Views that contain our
statistical information
select table_name
,sum(decode(column_name,’SID’,1,’SESSION_ID’,1,0)) SID
,sum(decode(column_name,’CLIENT_ID’,1,’CLIENT_IDENTIFIER’,1,0)) CLIENT_ID
,sum(decode(column_name,’SERVICE_NAME’,1,0)) SERVICE_NAME
,sum(decode(column_name,’ACTION’,1,0)) ACTION
,sum(decode(column_name,’MODULE’,1,0)) MODULE
,sum(decode(column_name,’SERIAL#’,1,0)) SERIAL#
from (select owner,table_name,column_name
from dba_tab_columns
where owner = ‘SYS’
and column_name in (‘SID’, ‘SESSION_ID’,
‘CLIENT_ID’, ‘CLIENT_IDENTIFIER’,
‘SERVICE_NAME’, ‘ACTION’, ‘MODULE’, ‘SERIAL#’))
group by table_name
order by table_name
/CLIENT SERVICE
TABLE_NAME SID ID NAME ACTION MODULE SERIAL#
—————————— — —— ——- —— —— ——-
DBA_HIST_ACTIVE_SESS_HISTORY 1 1 0 1 1 0
V_$ACTIVE_SESSION_HISTORY 1 1 0 1 1 0
V_$CLIENT_STATS 0 1 0 0 0 0
V_$SERVICE_STATS 0 0 1 0 0 0
V_$SERV_MOD_ACT_STATS 0 0 1 1 1 0
Table 2
Table |
Description |
V_$ACTIVE_SESSION_HISTORY |
|
DBA_HIST_ACTIVE_SESS_HISTORY |
|
V_$CLIENT_STATS |
|
V_$SERVICE_STATS |
|
V_$SERV_MOD_ACT_STATS |
|
The use of these views is quite straightforward. You need
only query them for the statistical aggregation you have set up through the
DBMS_MONITOR package. The real difficulty lies in setting up those aggregations
stepped through in earlier parts of this series. Next time we will get into the
new reporting options available for traces in Oracle 10g.