Comments on: SQL_ID is just a fancy representation of hash value

By: SQL Plan Management | IT World

SQL Plan Management | IT World — Thu, 22 Dec 2011 14:49:37 +0000

[...] SQL_ID is just a fancy representation of hash value [...]

By: Narayana Rao

Narayana Rao — Thu, 18 Aug 2011 17:59:04 +0000

Tanel
on a 3 node rac (11.1.0), on node3, sql_id ‘X’ chooses good plan ‘A’, but on the node 2 & 3, the same sql_id ‘X’ chooses bad plan ‘Y’,

Question : what could be the reason,
can we drop the bad plan_hash_value , ? /

Thanks
NR

By: Tanel Poder

Tanel Poder — Sat, 23 Jul 2011 18:24:33 +0000

@Vishal Gupta It's just taking last 4 bytes of the 8 byte binary value, with acknowledging the different formats (base-32 vs base 10). The simple SQL code above in the article should explain the sequence of operations...

By: Vishal Gupta

Vishal Gupta — Mon, 04 Jul 2011 21:24:00 +0000

Tanel,

How did you work out the algorithm to convert the SQL_ID to HASH_VALUE? Can you please give some pointers?

By: satish

satish — Tue, 07 Jun 2011 14:14:01 +0000

@Greg
SELECT sql_handle, plan_name
FROM dba_sql_plan_baselines
WHERE signature IN (
SELECT exact_matching_signature FROM v$sql WHERE sql_id=’&SQL_ID’)
)
Thanks to Doug who has provided link in his blog which i am giving below.

http://intermediatesql.com/oracle/how-to-find-spm-baseline-by-sql_id/#more-639

By: Divide and conquer the “true” mutex contention « Latch, mutex and beyond

Sun, 01 May 2011 19:17:32 +0000

[...] ordinary hash value of this SQL is 3222383532. However, we need a complete 128 bit hash value for library cache object here. You can find it in kglhahsv column of [...]

By: How to find SPM baseline by sql_id « Intermediate SQL

How to find SPM baseline by sql_id « Intermediate SQL — Sun, 10 Apr 2011 23:27:15 +0000

[...] SQL_ID is just another representation of SQL text (you can read about it in Tanel Poder’s blog) [...]

By: SQL_ID, Plans, and Baselines, Oh My! | 140,000 Characters or Less

SQL_ID, Plans, and Baselines, Oh My! | 140,000 Characters or Less — Mon, 28 Feb 2011 15:58:50 +0000

[...] SQL_IDs do go away, but since they are just a hash value of the query object – then they should remain the same even after a hard-parse occurs. Or as I understand it after reading Tanel Poder’s (Twitter) excellent blog post on the subject (link): [...]

By: Greg Wang

Greg Wang — Sun, 13 Feb 2011 20:09:00 +0000

hello,
‘Plan baseline’ is introduced in Oracle 11g SQL plan mgmt feature. I wonder how do we relate the ‘signature’ , ‘sql_handle’ , or ‘plan_name’ column in the dba_sql_plan_baselines view to the SQL_ID, HASH_VALUE, or PLAN_HASH_VALUE in v$sql.

thanks!

By: Nasir

Nasir — Sat, 15 Jan 2011 19:41:24 +0000

Hi,
I am trying to get the same sql_ID which is coming from application,
i am getting the sql_text from v$sqlarea , the sql contains some binds , so before running the sql, i am settings those binds to the value which i need and running the query, however when i check the sql_id it is a different SQL_ID, how do i ensure that when i run the query i get the same exact sql_id , i am taking care so that even a single space is not coming , but still not able to replicate the sql_ID,

any suggestions/comments ?

thanks,