db2像oracle一样使用hints（guidelines）

Posted 2022-12-10 t0nsha

db2像oracle一样使用hints（guidelines） C:\\DB2>more f3.sql SELECT d.DEPTNAME,e.FIRSTNME,e.LASTNAME FROM DEPARTMENT D,EMPLOYEE E WHERE d.DEPTNO = e.WORKDEPT AND e.EMPNO LIKE '0001%' /*<OPTGUIDELINES> <MSJOIN> <TBSCAN TABLE='D'/> <TBSCAN TABLE='E'/> </MSJOIN> </OPTGUIDELINES>*/;
C:\\DB2> C:\\DB2>db2expln -d sample -f f3.sql -g -t -z ";"
DB2 Universal Database Version 10.5, 5622-044 (c) Copyright IBM Corp. 1991, 2012 Licensed Material - Program Property of IBM IBM DB2 Universal Database SQL and XQUERY Explain Tool
DB2 Universal Database Version 10.5, 5622-044 (c) Copyright IBM Corp. 1991, 2012 Licensed Material - Program Property of IBM IBM DB2 Universal Database SQL and XQUERY Explain Tool
******************** DYNAMIC ***************************************
==================== STATEMENT ==========================================
        Isolation Level          = Cursor Stability         Blocking                 = Block Unambiguous Cursors         Query Optimization Class = 5
        Partition Parallel       = No         Intra-Partition Parallel = No
        SQL Path                 = "SYSIBM", "SYSFUN", "SYSPROC", "SYSIBMADM",                                    "LIAO"

Statement:
  SELECT d.DEPTNAME, e.FIRSTNME, e.LASTNAME   FROM DEPARTMENT D, EMPLOYEE E   WHERE d.DEPTNO =e.WORKDEPT AND e.EMPNO LIKE '0001%'           /*<OPTGUIDELINES> <MSJOIN> <TBSCAN TABLE='D' /> <TBSCAN           TABLE='E' /> </MSJOIN> </OPTGUIDELINES>*/

Section Code Page = 1208
Estimated Cost = 13.634712 Estimated Cardinality = 9.816054
Access Table Name = LIAO.EMPLOYEE  ID = 2,6 |  Index Scan:  Name = LIAO.PK_EMPLOYEE  ID = 1 |  |  Regular Index (Not Clustered) |  |  Index Columns: |  |  |  1: EMPNO (Ascending) |  #Columns = 4 |  Skip Inserted Rows |  Avoid Locking Committed Data |  Currently Committed for Cursor Stability |  Evaluate Predicates Before Locking for Key |  #Key Columns = 1 |  |  Start Key: Inclusive Value |  |  |  1: '0001' |  |  Stop Key: Inclusive Value |  |  |  1: '0001　　' |  Data Prefetch: Sequential(0), Readahead |  Index Prefetch: None |  Lock Intents |  |  Table: Intent Share |  |  Row  : Next Key Share |  Sargable Predicate(s) |  |  Process Build Table for Hash Join Hash Join |  Early Out: Single Match Per Inner Row |  Estimated Build Size: 4000 |  Estimated Probe Size: 4000 |  Access Table Name = LIAO.DEPARTMENT  ID = 2,5 |  |  #Columns = 2 |  |  Skip Inserted Rows |  |  Avoid Locking Committed Data |  |  Currently Committed for Cusor Stability |  |  May participate in Scan Sharing structures |  |  Scan may start anywhere and wrap, for completion |  |  Fast scan, for purposes of scan sharing management |  |  Scan can be throttled in scan sharing management |  |  Relation Scan |  |  |  Prefetch: Eligible |  |  Lock Intents |  |  |  Table: Intent Share |  |  |  Row  : Next Key Share |  |  Sargable Predicate(s) |  |  |  Process Probe Table for Hash Join Return Data to Application |  #Columns = 3
End of section

Optimizer Plan:
              Rows             Operator               (ID)               Cost
            9.81605             RETURN              ( 1)             13.6347               |             9.81605             HSJOIN              ( 2)             13.6347            /       \\      14              9.81605    TBSCAN             FETCH     ( 3)              ( 4)    6.81583           6.8181      |              /       \\      14        9.81605       42  Table:         IXSCAN    Table:  LIAO            ( 5)     LIAO  DEPARTMENT   0.00986447  EMPLOYEE                  |                  42              Index:              LIAO              PK_EMPLOYEE


C:\\DB2>db2set DB2_OPTPROFILE=YES
C:\\DB2>db2set -all [e] DB2PATH=C:\\v105\\IBM\\SQLLIB [i] DB2_OPTPROFILE=YES [i] DB2INSTOWNER=LIAO-PC [i] DB2PORTRANGE=60000:60005 [i] DB2INSTPROF=C:\\V105\\PROGRAMDATA\\\\IBM\\DB2\\DB2COPY1 [i] DB2COMM=TCPIP [g] DB2_EXTSECURITY=NO [g] DB2_COMMON_APP_DATA_PATH=C:\\v105\\ProgramData\\ [g] DB2SYSTEM=LIAO-PC [g] DB2PATH=C:\\v105\\IBM\\SQLLIB [g] DB2INSTDEF=DB2 [g] DB2ADMINSERVER=DB2DAS00
C:\\DB2>db2stop 2015-12-04 00:43:34     0   0   SQL1025N  未停止数据库，因为数据库仍是活动的。 SQL1025N  未停止数据库，因为数据库仍是活动的。
C:\\DB2>db2stop force 2015-12-04 00:43:40     0   0   SQL1064N  DB2STOP 处理成功。 SQL1064N  DB2STOP 处理成功。
C:\\DB2>db2start 2015-12-04 00:43:48     0   0   SQL1063N  DB2START 处理成功。 SQL1063N  DB2START 处理成功。
C:\\DB2>db2expln -d sample -f f3.sql -g -t -z ";"
DB2 Universal Database Version 10.5, 5622-044 (c) Copyright IBM Corp. 1991, 2012 Licensed Material - Program Property of IBM IBM DB2 Universal Database SQL and XQUERY Explain Tool
DB2 Universal Database Version 10.5, 5622-044 (c) Copyright IBM Corp. 1991, 2012 Licensed Material - Program Property of IBM IBM DB2 Universal Database SQL and XQUERY Explain Tool
******************** DYNAMIC ***************************************
==================== STATEMENT ==========================================
        Isolation Level          = Cursor Stability         Blocking                 = Block Unambiguous Cursors         Query Optimization Class = 5
        Partition Parallel       = No         Intra-Partition Parallel = No
        SQL Path                 = "SYSIBM", "SYSFUN", "SYSPROC", "SYSIBMADM",                                    "LIAO"

Statement:
  SELECT d.DEPTNAME, e.FIRSTNME, e.LASTNAME   FROM DEPARTMENT D, EMPLOYEE E   WHERE d.DEPTNO =e.WORKDEPT AND e.EMPNO LIKE '0001%'           /*<OPTGUIDELINES> <MSJOIN> <TBSCAN TABLE='D' /> <TBSCAN           TABLE='E' /> </MSJOIN> </OPTGUIDELINES>*/

Section Code Page = 1208
Estimated Cost = 13.648438 Estimated Cardinality = 9.816054
Access Table Name = LIAO.DEPARTMENT  ID = 2,5 |  #Columns = 2 |  Skip Inserted Rows |  Avoid Locking Committed Data |  Currently Committed for Cursor Stability |  May participate in Scan Sharing structures |  Scan may start anywhere and wrap, for completion |  Fast scan, for purposes of scan sharing management |  Scan can be throttled in scan sharing management |  Relation Scan |  |  Prefetch: Eligible |  Lock Intents |  |  Table: Intent Share |  |  Row  : Next Key Share |  Sargable Predicate(s) |  |  Insert Into Sorted Temp Table  ID = t1 |  |  |  #Columns = 2 |  |  |  #Sort Key Columns = 1 |  |  |  |  Key 1: DEPTNO (Ascending) |  |  |  Sortheap Allocation Parameters: |  |  |  |  #Rows     = 14.000000 |  |  |  |  Row Width = 28 |  |  |  Piped Sorted Temp Table Completion  ID = t1 Access Temp Table  ID = t1 |  #Columns = 2 |  Relation Scan |  |  Prefetch: Eligible Merge Join |  Access Table Name = LIAO.EMPLOYEE  ID = 2,6 |  |  #Columns = 4 |  |  Skip Inserted Rows |  |  Avoid Locking Committed Data |  |  Currently Committed for Cursor Stability |  |  May participate in Scan Sharing structures |  |  Scan may start anywhere and wrap, for completion |  |  Fast scan, for purposes of scan sharing management |  |  Scan can be throttled in scan sharing management |  |  Relation Scan |  |  |  Prefetch: Eligible |  |  Lock Intents |  |  |  Table: Intent Share |  |  |  Row  : Next Key Share |  |  Sargable Predicate(s) |  |  |  #Predicates = 1 |  |  |  Insert Into Sorted Temp Table  ID = t2 |  |  |  |  #Columns = 3 |  |  |  |  #Sort Key Columns = 1 |  |  |  |  |  Key 1: WORKDEPT (Ascending) |  |  |  |  Sortheap Allocation Parameters: |  |  |  |  |  #Rows     = 10.000000 |  |  |  |  |  Row Width = 32 |  |  |  |  Piped |  Sorted Temp Table Completion  ID = t2 |  Access Temp Table  ID = t2 |  |  #Columns = 3 |  |  Relation Scan |  |  |  Prefetch: Eligible Return Data to Application |  #Columns = 3
End of section

Optimizer Plan:
         Rows        Operator          (ID)          Cost
       9.81605        RETURN         ( 1)        13.6484          |        9.81605        MSJOIN         ( 2)        13.6484       /       \\-\\      14          *    TBSCAN       |     ( 3)      9.81605    6.81692    TBSCAN      |         ( 7)      14       6.83002     SORT        |     ( 4)      9.81605    6.81674     SORT      |         ( 8)      14       6.82983    TBSCAN       |     ( 5)      9.81605    6.81583    TBSCAN      |         ( 9)      14       6.82912  Table:         |  LIAO           42  DEPARTMENT  Table:              LIAO              EMPLOYEE



C:\\DB2>
REF: 1.Oracle hint在DB2中的实现-访问计划定制 http://www.itpub.net/thread-1795527-1-1.html