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Toad for DB2 7.0 - Installation Guide

Generate Explain Plans

The explain plan displays the steps a database uses to execute an SQL statement. The results of the plan display the order a database uses to search/join tables, the types of access used (indexed search or full table scan), and the names of indexes used. If you are using cost-based optimization, this statement also determines the cost of executing the statement. You can use explain plans to help tune SQL to improve performance.

Toad automatically generates an estimated explain plan when you select the Explain Plan tab in the Results pane.

Tip: If you occasionally closed the Results pane, you can restore it by selecting Editor | Windows | Script Results.

To generate an estimated explain plan

  • Click in the Editor toolbar.

The following is a list of abbreviations used in DB2 Explain Plan:

Value Description

DELETE

Delete

EISCAN

Extended Index Scan

FETCH

Fetch

FILTER

Filter rows

GENROW

Generate Row

GRPBY

Group By

HSJOIN

Hash Join

INSERT

Insert

IXAND

Dynamic Bitmap Index ANDing

IXSCAN

Relational index scan

MSJOIN

Merge Scan Join

NLJOIN

Nested loop Join

REBAL

Rebalance rows between SMP subagents

RETURN

Result

RIDSCN

Row Identifier (RID) Scan

RPD

Remote PushDown

SHIP

Ship query to remote system

SORT

Sort

TBFUNC

In-stream table function operator

TBSCAN

Table Scan

TEMP

Temporary Table Construction

TQ

Table Queue

UNION

Union

UNIQUE

Duplicate Elimination

UPDATE

Update

XISCAN

Index scan over XML data

XSCAN

XML document navigation scan

XANDOR

Index ANDing and ORing over XML data

ZZJOIN

Zigzag join

  

Related Topics

View Result Sets 

View Execution Log Messages 

Related Documents