Query regarding the ADDM Report

Question

Hi All,
My DB performance was quite slow during the last weekend because we had a major data load job and dbms_stats.gather_schema_stats jobs running simultaneously. So, we got an ADDM report generated for these 2 days and from that i could extract 2 things:
1. The performance was slow because the dbms_stats.gather_schema_stats job was running simultaneoulsy on it.
2. I could see that some of the SELECT queries on the tables in the schema got executed 145445335, 35, 30 and 20 times repeatedly on the DB. Now this leaves me shocked. Can anyone possibly explain the reason behind it? Was it because a gather_schema_stats was also running on the DB? But how would a select be affected by it? Would it be because it had a exclusive locks on those DB objects during the time it was running?
Kindly suggest.
Thanks in advance.

Answer 1

Hi,
Thanks for your response.
No, i cannot see any of the terms like library cache locks and library cache pins with those SQL statements. The only things is see is:
RECOMMENDATION 1: SQL Tuning, 15% benefit (28820 seconds)
ACTION: Run SQL Tuning Advisor on the SQL statement with SQL_ID
"725bgkkhqs73v".
RELEVANT OBJECT: SQL statement with SQL_ID 725bgkkhqs73v and
PLAN_HASH 2688602638
SELECT column1 from table1;
ACTION: Investigate the SQL statement with SQL_ID "725bgkkhqs73v" for
possible performance improvements.
RELEVANT OBJECT: SQL statement with SQL_ID 725bgkkhqs73v and
PLAN_HASH 2688602638
RATIONALE: SQL statement with SQL_ID "725bgkkhqs73v" was executed 32
times and had an average elapsed time of 900 seconds.
Also, my DB is 10.2.0.3.0 and OS is HP-UNX B.11.23.