Solved

Need hint help in existing sql

Posted on 2014-03-25
3
443 Views
Last Modified: 2014-03-25
Hello Experts,

I have the below SQL :

EXPLAIN PLAN FOR 
SELECT  QST_RESPONSE ,
  QST_RESPONSE_ATTACHMENT ,
  QST_RESPONSE_DATE ,
  QST_ALL_AREAS ,
  QST_APPLE_DEDICATED_AREAS ,
  QST_NON_PRODUCTION_UTILITIES ,
  QST_PRODUCTION_AREAS_DEDICATED ,
  QST_COMMON_PRODUCTION_USED
FROM MS_SRA_VISIT_QUESTIONS
WHERE QUESTION_ID                          = :B2
AND REGEXP_SUBSTR(VISIT_ID ,'[^-]+' ,1 ,2) = :B1
AND QST_TYPE                              <> '1'
AND DD_CREATED_ON                          =
  (SELECT /*+ index_ss(QS MS_SRA_VISIT_QUESTIONS_PK) */ MAX(qs.DD_CREATED_ON)
  FROM MS_SRA_VISIT_QUESTIONS QS
  WHERE QS.QUESTION_ID                          = :B2
  AND REGEXP_SUBSTR(QS.VISIT_ID ,'[^-]+' ,1 ,2) = :B1
  AND qs.QST_TYPE                              <> '1'
  ) ;

Open in new window



Plan hash value: 283024080
 
-----------------------------------------------------------------------------------------------------------
| Id  | Operation                     | Name                      | Rows  | Bytes | Cost (%CPU)| Time     |
-----------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT              |                           |     1 |  1290 |    80   (0)| 00:00:01 |
|*  1 |  TABLE ACCESS BY INDEX ROWID  | MS_SRA_VISIT_QUESTIONS    |     1 |  1290 |    40   (0)| 00:00:01 |
|*  2 |   INDEX SKIP SCAN             | MS_SRA_VISIT_QUESTIONS_PK |     1 |       |    40   (0)| 00:00:01 |
|   3 |   SORT AGGREGATE              |                           |     1 |    32 |            |          |
|*  4 |    TABLE ACCESS BY INDEX ROWID| MS_SRA_VISIT_QUESTIONS    |     1 |    32 |    40   (0)| 00:00:01 |
|*  5 |     INDEX SKIP SCAN           | MS_SRA_VISIT_QUESTIONS_PK |     1 |       |    40   (0)| 00:00:01 |
-----------------------------------------------------------------------------------------------------------
 
Outline Data
-------------
 
  /*+
      BEGIN_OUTLINE_DATA
      INDEX_SS(@"SEL$2" "QS"@"SEL$2" ("MS_SRA_VISIT_QUESTIONS"."VISIT_ID" 
              "MS_SRA_VISIT_QUESTIONS"."QUESTION_ID" "MS_SRA_VISIT_QUESTIONS"."QST_SOURCE_OBJECT_TYPE"))
      PUSH_SUBQ(@"SEL$2")
      INDEX_SS(@"SEL$1" "MS_SRA_VISIT_QUESTIONS"@"SEL$1" ("MS_SRA_VISIT_QUESTIONS"."VISIT_ID" 
              "MS_SRA_VISIT_QUESTIONS"."QUESTION_ID" "MS_SRA_VISIT_QUESTIONS"."QST_SOURCE_OBJECT_TYPE"))
      OUTLINE_LEAF(@"SEL$1")
      OUTLINE_LEAF(@"SEL$2")
      ALL_ROWS
      OPT_PARAM('optimizer_index_cost_adj' 40)
      OPT_PARAM('star_transformation_enabled' 'true')
      OPT_PARAM('_gby_hash_aggregation_enabled' 'false')
      OPT_PARAM('_optimizer_cost_based_transformation' 'off')
      OPT_PARAM('_optim_peek_user_binds' 'false')
      OPT_PARAM('_index_join_enabled' 'false')
      OPT_PARAM('query_rewrite_enabled' 'false')
      OPT_PARAM('_complex_view_merging' 'false')
      OPT_PARAM('_b_tree_bitmap_plans' 'false')
      DB_VERSION('11.2.0.3')
      OPTIMIZER_FEATURES_ENABLE('11.2.0.3')
      IGNORE_OPTIM_EMBEDDED_HINTS
      END_OUTLINE_DATA
  */
 
Predicate Information (identified by operation id):
---------------------------------------------------
 
   1 - filter("QST_TYPE"<>'1' AND "DD_CREATED_ON"= (SELECT /*+ INDEX_SS ("QS" 
              "MS_SRA_VISIT_QUESTIONS_PK") */ MAX("QS"."DD_CREATED_ON") FROM "MS_SRA_VISIT_QUESTIONS" "QS" WHERE 
              "QS"."QST_TYPE"<>'1' AND "QS"."QUESTION_ID"=TO_NUMBER(:B2) AND  REGEXP_SUBSTR 
              ("QS"."VISIT_ID",'[^-]+',1,2)=:B1))
   2 - access("QUESTION_ID"=TO_NUMBER(:B2))
       filter("QUESTION_ID"=TO_NUMBER(:B2) AND  REGEXP_SUBSTR ("VISIT_ID",'[^-]+',1,2)=:B1)
   4 - filter("QS"."QST_TYPE"<>'1')
   5 - access("QS"."QUESTION_ID"=TO_NUMBER(:B2))
       filter("QS"."QUESTION_ID"=TO_NUMBER(:B2) AND  REGEXP_SUBSTR 
              ("QS"."VISIT_ID",'[^-]+',1,2)=:B1)

Open in new window



Want to change in such a way that the indexes should not be skiped and also the way IN condition are been used.
0
Comment
Question by:Swadhin Ray
3 Comments
 
LVL 34

Expert Comment

by:johnsone
ID: 39953067
The index is not being skipped.  The index is still being used.  The index being used is a composite index (it has more than one column).  The first column in the index (VISIT_ID) cannot be used because of the REGEXPR_SUBSTR call on it.  However, QUESTION_ID (the second column in the index) can be used.  Oracle is smart enough now to be able to used that index to search for QUESTION_ID.

If you want an index range scan instead of an index skip scan, then create an index on QUESTION_ID.  If you do that, I would probably add DD_CREATED_ON as a second column in that index.  You may already have that indexed, but with the hint you have, you are forcing an index to be used.

You may also consider a function based index on the REGEXP_SUBSTR.  Not sure if you would get good cardinality there or not.
0
 
LVL 73

Accepted Solution

by:
sdstuber earned 500 total points
ID: 39953230
rather than querying the table twice, have you considered using an analytic?


SELECT qst_response,
       qst_response_attachment,
       qst_response_date,
       qst_all_areas,
       qst_apple_dedicated_areas,
       qst_non_production_utilities,
       qst_production_areas_dedicated,
       qst_common_production_used
  FROM (SELECT qst_response,
               qst_response_attachment,
               qst_response_date,
               qst_all_areas,
               qst_apple_dedicated_areas,
               qst_non_production_utilities,
               qst_production_areas_dedicated,
               qst_common_production_used,
               RANK() OVER (ORDER BY dd_created_on DESC) r
          FROM ms_sra_visit_questions
         WHERE question_id = :b2
           AND REGEXP_SUBSTR(
                   visit_id,
                   '[^-]+',
                   1,
                   2
               ) = :b1
           AND qst_type <> '1')
 WHERE r = 1;


if the dd_created_on will be unique then you could use row_number() instead of rank()
0
 
LVL 16

Author Closing Comment

by:Swadhin Ray
ID: 39955098
thanks a lot
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

This article started out as an Experts-Exchange question, which then grew into a quick tip to go along with an IOUG presentation for the Collaborate confernce and then later grew again into a full blown article with expanded functionality and legacy…
Subquery in Oracle: Sub queries are one of advance queries in oracle. Types of advance queries: •      Sub Queries •      Hierarchical Queries •      Set Operators Sub queries are know as the query called from another query or another subquery. It can …
This video shows how to configure and send email from and Oracle database using both UTL_SMTP and UTL_MAIL, as well as comparing UTL_SMTP to a manual SMTP conversation with a mail server.
This video shows how to copy an entire tablespace from one database to another database using Transportable Tablespace functionality.

911 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

22 Experts available now in Live!

Get 1:1 Help Now