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Bad Performance Of The Audit Vault Database Caused By The Collectors (Doc ID 1072926.1)

Last updated on MARCH 10, 2019

Applies to:

Oracle Audit Vault - Version 10.2.3.2 and later
Information in this document applies to any platform.

Symptoms

NOTE: In the images and/or the document content below, the user information and data used represents fictitious data from the Oracle sample schema(s) or Public Documentation delivered with an Oracle database product. Any similarity to actual persons, living or dead, is purely coincidental and not intended in any manner. 

On the Audit Vault database the processes created by the collectors are consuming much of the CPU power. The AWR reports show that there are significant waits caused by sequence contention. 

Normally the sequences associated with the AV DW dimension tables have a cache of 20. If the cache is increased to 2000 there are no more waits but the CPU usage will increase even more. This problem can happen for any dimension if that dimension has a large number of rows. For example the collectors and the AV database are slow whenever the TARGET dimension has a large number of  rows for a certain OWNER.

SQL> select count(*), substr(owner_name,1,20) from target_dim group by owner_name order by 1 desc


COUNT(*)       OWNER_NAME
--------       -----------------------------------------------------------
   16227       USER1
      59       TEST_DBA
       7       SYSMAN
       7
       6       USER1
       6       DBSNMP
       4       TEST
       3       ORALINUX
       3       ORA_LINUX


 We see that USER1 has many targets compared to the other owners. Because of  this while the collector is running the following statement is consuming a  lot of resources and has a lot of waits :

MERGE INTO AVSYS.TARGET_DIM USING (SELECT :B1 TARGET_OWNER FROM DUAL) D ON
(TARGET_DIM.OWNER_NAME = D.TARGET_OWNER) WHEN NOT MATCHED THEN INSERT (
TARGET_DIM.DIMENSION_KEY, TARGET_DIM.OWNER_ID, TARGET_DIM.OWNER_NAME )
VALUES ( TARGET_DIM_SEQ.NEXTVAL, TARGET_DIM_SEQ.CURRVAL, D.TARGET_OWNER )
LOG ERRORS (TO_CHAR(SYSDATE, 'dd-mon-yy')) REJECT LIMIT UNLIMITED


call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 0 0.00 0.00 0 0 0 0
Execute 53 67.29 111.09 0 7062 44139 0
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 53 67.29 111.09 0 7062 44139 0

Misses in library cache during parse: 0
Optimizer mode: ALL_ROWS
Parsing user id: 46 (AVSYS) (recursive depth: 2)



These symptoms can be seen only after the upgrade to 10.2.3.2 since in earlier AV versions the collectors are not updating the data warehouse fact table or the dimension tables.

Changes

 

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References


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