v$sql_cs_statistics bug in 12c?

I think I’ve run across a bug in 12c where v$sql_cs_statistics is not populated in 12c as it was in 11.2.0.3.

I’ve messed with adaptive cursor sharing using an example on Tim Hall’s web site: web example

I’ve tried to break it and change it in various ways to understand adaptive cursor sharing.  I was using some 11g databases and on those systems the example results in output from v$sql_cs_statistics.  But in 12c the view returns nothing.  Maybe this is normal but it seems bug like to me.

Here is a zip of my version of Tim’s example and it’s output on an 11.2.0.3 and 12.1 database: zip

In the working 11.2.0.3 example you have this output from v$sql_cs_statistics:

ORCL::SYSTEM>SELECT * FROM v$sql_cs_statistics WHERE sql_id = '9bmm6cmwa8saf';

ADDRESS          HASH_VALUE SQL_ID        CHILD_NUMBER BIND_SET_HASH_VALUE P EXECUTIONS ROWS_PROCESSED BUFFER_GETS   CPU_TIME
---------------- ---------- ------------- ------------ ------------------- - ---------- -------------- ----------- ----------
0000000089035390 4171522382 9bmm6cmwa8saf            1          2064090006 Y          1          50001         501          0
0000000089035390 4171522382 9bmm6cmwa8saf            0          2342552567 Y          1              3           3          0

On 12c you get nothing:

ORCL:CDB$ROOT:SYSTEM>SELECT * FROM v$sql_cs_statistics WHERE sql_id = '9bmm6cmwa8saf';

no rows selected

The other queries in the example all return results so I guess it is a bug.

– Bobby

About Bobby

I live in Chandler, Arizona with my wife and three daughters. I work for US Foods, the second largest food distribution company in the United States. I have worked in the Information Technology field since 1989. I have a passion for Oracle database performance tuning because I enjoy challenging technical problems that require an understanding of computer science. I enjoy communicating with people about my work.
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2 Responses to v$sql_cs_statistics bug in 12c?

  1. Anonymous says:

    it’s not a bug, change the behavior for some performance purpose.

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