Neoview Query Guide (R2.2)

Table of Contents
About This Document.........................................................................................................9
Supported Release Version Updates (RVUs)..........................................................................................9
Intended Audience.................................................................................................................................9
New and Changed Information in This Edition.....................................................................................9
Document Organization.........................................................................................................................9
Notation Conventions.............................................................................................................................9
General Syntax Notation...................................................................................................................9
Related Documentation........................................................................................................................11
Neoview Customer Library.............................................................................................................11
Publishing History................................................................................................................................12
HP Encourages Your Comments..........................................................................................................12
1 Using Explain...............................................................................................................13
Difference Between EXPLAIN Statement and EXPLAIN Function.....................................................13
Capturing Query Plans for Review......................................................................................................13
Capturing Query Plans....................................................................................................................13
Historical Explain Database.......................................................................................................14
Capturing Query Plan Example.................................................................................................14
Querying the Explain Table.............................................................................................................16
2 Using Visual Query Planner........................................................................................19
Downloading VQP................................................................................................................................19
Installing VQP.......................................................................................................................................19
Uninstalling VQP..................................................................................................................................20
Using the VQP Interface ......................................................................................................................20
VQP Requirements..........................................................................................................................20
Getting Help for VQP......................................................................................................................20
Graphically Displaying Execution Plans.........................................................................................20
Selecting Tasks on the Toolbar.........................................................................................................23
Accessing Additional Information About Operators......................................................................24
Node Details...............................................................................................................................25
Reviewing the Cost Details........................................................................................................26
Additional Table Information ....................................................................................................26
Understanding the Query Plan in VQP................................................................................................27
Process Architecture For a Query....................................................................................................28
The SPLIT_TOP Operator..........................................................................................................29
DAM and ESP Parallelism...............................................................................................................30
3 Query Plan Operators.................................................................................................31
Operators and Description Fields.........................................................................................................32
Operators Used for Parallelism or as Process Boundaries..............................................................32
ROOT Operator..........................................................................................................................33
ESP_EXCHANGE Operator.......................................................................................................34
PARTITION_ACCESS Operator................................................................................................35
SPLIT_TOP Operator.................................................................................................................36
Understanding Joins.............................................................................................................................36
Nested Joins.....................................................................................................................................37
NESTED_JOIN Operator............................................................................................................37
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