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SQL Optimizer for SAP ASE 3.8 - Release Notes

Statistics Tab

The Statistics tab of the Run Time pane in the Index Advisor window shows the accumulative totals for the CPU Time, Scan Count, Logical Reads, Physical Reads, and Read-Ahead Reads from the execution of the SQL statement with each index alternative. To see the individual values for the statistics by table, click All Records or First Record on the top right pane or the Statistics tab at the bottom of the Index Advisor window.

For Index candidates proposed by the Index Advisor, an icon is added in the far left column to indicate if the proposed index is used in the query plan. A key with a green checkmark image\I_Key_PlanChangedByIndexes.gif indicates that the query plan is changed by the proposed index. A key with a red exclamation mark image\I_Key_PlanChangedIndexNotApplied.gif indicates that the query plan changed, but that the proposed index was not used by the new query plan. A key with a red x image\I_Key_PlanNoChange.gif indicates that the query plan is not changed by the addition of the proposed index. In this case, the SQL statement is not executed by the by the Batch Run.

For more information about this statistics see the Adaptive Server Performance Tuning: Monitor and Analyzing manual, Chapter 4.

Item Description

Elapsed Time

(All Records and First Record)  

The Elapsed Time is the time (in clock time) that it takes the SQL statement to select all records or the first record. This figure may include time that Adaptive Server spent on processing other tasks or waiting for disk or network I/O to complete. This is the accumulative run time for the SQL statement. The individual values for the Elapsed Time can be view by clicking All Records or First Record on the top right pane of the SQL Optimizer window.

CPU Time

(All Records and First Record)  

The CPU Time is accumulative total for the CPU time to execute the SQL statement. The individual values for the CPU time can be view by clicking All Records or First Record on the top right pane of the SQL Optimizer window.

Actual I/O Cost

(All Records and First Record)  

This Actual I/O Cost is a calculation from Adaptive Server after the SQL statement was executed in the Batch Run or the Run Time function.

Writes

(All Records and First Record)  

The Writes is the total number of buffers written to the disk.

Scan Count

(All Records and First Record)  

The Scan Count represents the number of times a query accessed a particular table.

Logical Reads

(All Records and First Record)  

The Logical Reads represents the accumulative total for logical read for each table and index used in the SQL statement.

Physical Reads

(All Records and First Record)  

The Physical Reads represents the accumulative total for logical read for each table and index used in the SQL statement.

APF IOs used

(All Records and First Record)  

The APF (Asynchronous-PreFetch) IOs used is the I/O the server does in advance anticipating which pages will need to be read next, so that the pages will be in cache when the process actually tries to access them.

 

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