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SQL Optimizer for SAP ASE 3.9.1 - User Guide

Introduction Tutorials Preferences Editor Functions SQL Information and Functions Performance Monitor SQL Inspector SQL Collector for Monitor Server SQL Scanner Index Advisor SQL Optimizer
SQL Optimizer Overview Optimization Engine Common Coding Errors in SQL Statements What Function Should l Use to Retrieve the Run Time? Unsatisfactory Performance Results SQL Optimizer Functions SQL Editor Optimized SQL Activity Log
SQL Worksheet SQL Formatter Database Explorer Code Finder Object Extractor SQL Repository Index Impact Analyzer Index Usage Analyzer Configuration Analyzer Migration Analyzer Abstract Plan Manager User-Defined Temp Tables SQL History Legal Information

Index Advisor Tab

Index Advisor

Default prefix of index name: (Default: QUEST_SX_IDX)

Enter the prefix that is placed on the index name when the Index Advisor automatically generates index candidates.

Calculate selectivity of indexes using a default sampling size of:

The selectivity is calculated from the number of rows that are selected from the table. The number of rows selected is determined by the following settings:

Top percentage of rows from table (Default = 10)

This number is used as a percentage to calculate the number of rows in the table that are retrieved in the sample which determines the selectivity of the data. You see the number of row used in the sample in the Select tables window.

Minimum number of rows (Default = 1000

This is the minimum number of rows that are used in the sample which determines the selectivity of the data. This number is used if the calculation using the percentage of the table is below this value.

Maximum number of rows (Default = 10000)

This is the maximum number of rows that are used in the sample which determines the selectivity of the data. This number is used if the calculation using the percentage of the table is above this value.

Do not advise indexes for tables with row count less than (Default = 500)

Specify the number of rows that a table must have before index candidates are generated for any columns in that table.

Evaluate columns in SELECT list (Default = cleared)

For SELECT SQL statements, specify whether the columns in the SELECT list are considered when generating the alternative indexes.

Maximum number of columns in a composite index (Default = 4)

Specify the maximum number of columns that are placed in a composite index.

Maximum number of indexes to advise per table usage (Default = 3)

Specific the maximum number of indexes that the Index Advisor creates for each table in the SQL statement.

 

Related Topic

Directory Setup Tab

Directory Setup

The Directory Setup tab of the Preferences window allows you to define the directory for saving and opening files used in the different modules.

Directory (1)

Set up directories for the Activity Log, the SQL History, the SQL Scanner, the SQL Collector for Monitor Server, and SQL Inspector modules. Also, set-up the directory for opening and saving files in several modules.

Directory (2)

Set up the directories for all the Analyzer modules and SQL Repository.

 

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