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IT39352: XML INDEXES NOT USED IN DB2 11.5 EXPLAIN PLAN

A fix is available

Db2 Version 11.1 Mod 4 Fix Pack 7 for Linux, UNIX, and Windows

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • Used in 10.5:

******************** EXPLAIN INSTANCE ********************

DB2_VERSION:       10.05.A
FORMATTED ON DB:   SAMPLE
SOURCE_NAME:       SQLC2K26
SOURCE_SCHEMA:     NULLID
SOURCE_VERSION:
EXPLAIN_TIME:      2020-04-21-15.51.15.269964
EXPLAIN_REQUESTER: DB2INST1

Original Statement:
------------------
SELECT
  T1.ID,
  T1.DATA,
  T1.ID
FROM
  db2inst1.TABLE1 T1
WHERE
  (T1.ID = 'test')
FOR FETCH ONLY
  OPTIMIZE FOR 1 ROW

Optimized Statement:
-------------------
SELECT
  $INTERNAL_XMLTOSQL$(Q1.$C0) AS "ID",
  $INTERNAL_XMLTOSQL$(Q1.$C1) AS "DATA",
  $INTERNAL_XMLTOSQL$(Q1.$C0) AS "ID"
FROM
  $INTERNAL_FOR$ ((TABLE ($INTERNAL_XPATH$
('($INTERNAL_XMLTOXML_NIEO$(Q2.XMLDATA))/estimate/{ID/./(.[((.
>= $INTERNAL_SQLTOXML$(RTRIM(:L0))) and (. <
$INTERNAL_FUNC$()))])(:-->$C0:),EventInfo/AssignmentEvent/(Inspe
ctionDateTime)(:-->$C1:)}'))) AS Q1),
  db2inst1.TABLE2 AS Q2
WHERE
  ($INTERNAL_XMLTOSQL$(Q1.$C0) = :L0)

Access Plan:
-----------
        Total Cost:             7.7278e+06
        Query Degree:           1

                 Rows
                RETURN
                (   1)
                 Cost
                  I/O
                  |
              1.11147e-05
                NLJOIN
                (   2)
              7.7278e+06
              1.13528e+06
               /--+--\
           167249  6.64561e-11
           FETCH     XSCAN
           (   3)    (   7)
           132621    45.4123
           131788       6
         /---+----\
     167249     1.19344e+06
     RIDSCN   TABLE: db2inst1
     (   4)    TABLE2
     1050.71        Q2
       123
       |
     167249
     SORT
     (   5)
     1050.71
       123
       |
     167249
     XISCAN
     (   6)
     941.878
       123
       |
   1.19344e+06
XMLIN: db2inst1
TABLE2_D4
       Q2


But not in 11.5:

******************** EXPLAIN INSTANCE ********************

DB2_VERSION:       11.05.0
FORMATTED ON DB:   SAMPLE
SOURCE_NAME:       SQLC2O29
SOURCE_SCHEMA:     NULLID
SOURCE_VERSION:
EXPLAIN_TIME:      2020-04-21-15.45.24.238406
EXPLAIN_REQUESTER: DB2INST1

Original Statement:
------------------
SELECT
  T1.ID,
  T1.DATA,
  T1.ID
FROM
  db2inst1.TABLE1 T1
WHERE
  (T1.ID = 'test')
FOR FETCH ONLY
  OPTIMIZE FOR 1 ROW

Optimized Statement:
-------------------
SELECT
  $INTERNAL_XMLTOSQL$(Q1.$C1) AS "ID",
  $INTERNAL_XMLTOSQL$(Q1.$C0) AS "DATA",
  $INTERNAL_XMLTOSQL$(Q1.$C1) AS "ID"
FROM
  $INTERNAL_FOR$ ((TABLE ($INTERNAL_XPATH$
('($INTERNAL_XMLTOXML_NIEO$(Q2.XMLDATA))/estimate/{EventInfo/Ass
ignmentEvent/(InspectionDateTime)(:-->$C0:),(ID)(:-->$C1:)}')))
AS Q1),
  db2inst1.TABLE2 AS Q2
WHERE
  ($INTERNAL_XMLTOSQL$(Q1.$C1) = :L0)

Access Plan:
-----------
        Total Cost:             3.24676e+07
        Query Degree:           1


          Rows
         RETURN
         (   1)
          Cost
           I/O
           |
         15204.1
         NLJOIN
         (   2)
       3.24676e+07
       4.6992e+06
         /-+--\
     844914  0.0179949
     TBSCAN   XSCAN
     (   3)   (   4)
     474844   37.8651
     474628      5
       |
     844914
TABLE: db2inst1
  TABLE2
       Q2

Local fix

  • N/A

Problem summary

  • ****************************************************************
* USERS AFFECTED:                                              *
* all                                                          *
****************************************************************
* PROBLEM DESCRIPTION:                                         *
* See Error Description                                        *
****************************************************************
* RECOMMENDATION:                                              *
* Upgrade to 11.1.4.7                                          *
****************************************************************

Problem conclusion

  • Upgrade to 11.1.4.7

Temporary fix

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IT39352
    • 

  • Reported component name
    DB2 FOR LUW
    • 

  • Reported component ID
    DB2FORLUW
    • 

  • Reported release
    B10
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt / Xsystem
    • 

  • Submitted date
    2021-12-09
    • 

  • Closed date
    2022-04-17
    • 

  • Last modified date
    2022-04-17
    • 





    

  • APAR is sysrouted FROM one or more of the following:
    

    
IT32664
    

    • 

  • APAR is sysrouted TO one or more of the following:
    

    • 



Fix information


    

  • Fixed component name
    DB2 FOR LUW
    • 

  • Fixed component ID
    DB2FORLUW
    • 



Applicable component levels


    

  • RB10  PSN
       UP
    • 








      
              
                            

              

              [{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSEPGG","label":"DB2 for Linux- UNIX and Windows"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"11.1","Line of Business":{"code":"LOB10","label":"Data and AI"}}]
              

                          

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            04 May 2022
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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