查看执行计划 db2expln 使用说明

单个语句：

d:/>db2expln -d wz20901 -u wzgladm wzglpass -t
-q "update MAT_MATERIAL set GATHERPLAN_ID=null where GATHERPLAN_ID =2005178 or GATHERPLAN_ID=32 "

DB2 Universal Database Version 8.1, 5622-044 (c) Copyright IBM Corp. 1991, 2002
Licensed Material - Program Property of IBM
IBM DB2 Universal Database SQL Explain Tool

DB2 Universal Database Version 8.1, 5622-044 (c) Copyright IBM Corp. 1991, 2002
Licensed Material - Program Property of IBM
IBM DB2 Universal Database SQL 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", "WZGLADM"

SQL Statement:

update MAT_MATERIAL set GATHERPLAN_ID=null
where GATHERPLAN_ID =2005178 or GATHERPLAN_ID=32

Section Code Page = 1386

Estimated Cost = 15083.518555
Estimated Cardinality = 940.719971

Access Table Name = WZGLADM.MAT_MATERIAL ID = 5,27
| #Columns = 1
| Relation Scan
| | Prefetch: Eligible
| Lock Intents
| | Table: Intent Exclusive
| | Row : Exclusive
Nested Loop Join
| Data Stream 1:
| | Not Piped
| | Table Constructor
| | | 2-Row(s)
| | Insert Into Temp Table ID = t1
| | | #Columns = 0
| End of Data Stream 1
| Access Temp Table ID = t1
| | #Columns = 0
| | Relation Scan
| | | Prefetch: Eligible
| | Sargable Predicate(s)
| | | #Predicates = 1
Update: Table Name = WZGLADM.MAT_MATERIAL ID = 5,27

End of section

d:/>

脚本：

d:/>db2expln -d wz20901 -u wzgladm wzglpass -t -z ; -f tmp.sql

DB2 Universal Database Version 8.1, 5622-044 (c) Copyright IBM Corp. 1991, 2002
Licensed Material - Program Property of IBM
IBM DB2 Universal Database SQL Explain Tool

DB2 Universal Database Version 8.1, 5622-044 (c) Copyright IBM Corp. 1991, 2002
Licensed Material - Program Property of IBM
IBM DB2 Universal Database SQL 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", "WZGLADM"

SQL Statement:

select GATHERPLAN_ID
from MAT_MATERIAL
where GATHERPLAN_ID=2005178 or GATHERPLAN_ID=5 or GATHERPLAN_ID=3

Section Code Page = 1386

Estimated Cost = 128.615417
Estimated Cardinality = 1411.079956

Table Constructor
| 3-Row(s)
Nested Loop Join
| Access Table Name = WZGLADM.MAT_MATERIAL ID = 5,27
| | Index Scan: Name = WZGLADM.MAT_IDX_GPLAN_ID ID = 4
| | | Regular Index (Not Clustered)
| | | Index Columns:
| | | | 1: GATHERPLAN_ID (Ascending)
| | #Columns = 1
| | #Key Columns = 1
| | | Start Key: Inclusive Value
| | | | | 1: ?
| | | Stop Key: Inclusive Value
| | | | | 1: ?
| | Index-Only Access
| | Index Prefetch: None
| | Lock Intents
| | | Table: Intent Share
| | | Row : Next Key Share
| | Sargable Index Predicate(s)
| | | Return Data to Application
| | | | #Columns = 1
Return Data Completion

End of section

对于稍微复杂的sql，建议使用questcentral中的 SQL turning 功能，比较直观。