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SQL Optimizer for Oracle 10.0 - User Guide

Welcome to SQL Optimizer
About SQL Optimizer SQL Optimization Workflow New in This Release Additional Resources Database Privileges Database Privileges Script Connect to the Database Windows Layout Customize Toolbars Keyboard Shortcuts Support Bundle Register SQL Optimizer Check for Updates SQL Operations
ALL PARTITION ALTER INDEX AND EQUAL ANTI JOIN BITMAP AND BITMAP COMPACTION BITMAP CONSTRUCTION BITMAP CONVERSION BITMAP INDEX BITMAP JOIN INDEX UPDATE BITMAP JOIN INDEX UPDATE STATEMENT BITMAP KEY ITERATION BITMAP MERGE BITMAP MINUS BITMAP OR BUFFER SORT CARTESIAN JOIN COLLECTION ITERATOR CONCATENATION CONNECT BY CONNECT BY PUMP COUNT COUNT STOPKEY CREATE AS SELECT CUBE SCAN DDL STATEMENT DELETE DOMAIN INDEX FAST FULL INDEX SCAN FILTER FIRST ROWS FIXED INDEX FIXED TABLE FOR UPDATE FULL INDEX SCAN FULL INDEX SCAN DESCENDING FULL INDEX SCAN (MIN/MAX) HASH GROUP BY HASH GROUP BY PIVOT HASH JOIN HASH JOIN BUFFERED HASH PARTITION HASH UNIQUE INDEX INDEX BUILD NON UNIQUE INDEX RANGE SCAN INDEX RANGE SCAN DESCENDING INDEX RANGE SCAN (MIN/MAX) INDEX SAMPLE FAST FULL SCAN INDEX SKIP SCAN INDEX SKIP SCAN DESCENDING INDEX UNIQUE SCAN INLIST ITERATOR INLIST PARTITION INSERT INTERSECTION INTO INVALID PARTITION ITERATOR PARTITION LOAD AS SELECT MAT_VIEW ACCESS MAT_VIEW REWRITE ACCESS MERGE JOIN MINUS MULTI-TABLE INSERT NESTED LOOPS OUTER JOIN PARTITION PARTITION HASH EMPTY PARTITION LIST PARTITION RANGE PROJECTION PX BLOCK ITERATOR PX COORDINATOR PX ITERATOR PX PARTITION PX PARTITION HASH ALL PX PARTITION LIST ALL PX PARTITION RANGE ALL PX RECEIVE PX SEND RANGE PARTITION RECURSIVE EXECUTION RECURSIVE WITH PUMP REFERENCE MODEL REMOTE SELECT SEMI JOIN SEQUENCE SINGLE PARTITION SINGLE RANGE PARTITION SORT SORT AGGREGATE SORT GROUP BY SORT GROUP BY CUBE SORT GROUP BY NOSORT SORT GROUP BY ROLLUP SORT JOIN SORT ORDER BY SORT UNIQUE SQL MODEL TABLE ACCESS TABLE ACCESS BY GLOBAL INDEX ROWID TABLE ACCESS BY INDEX ROWID TABLE ACCESS BY LOCAL INDEX ROWID TABLE ACCESS BY ROWID TABLE ACCESS BY USER ROWID TABLE ACCESS CLUSTER TABLE ACCESS FULL TABLE ACCESS HASH TABLE ACCESS SAMPLE TABLE QUEUE TEMP TABLE GENERATION TEMP TABLE TRANSFORMATION UNION UNION ALL UNION ALL (RECURSIVE WITH) UNPIVOT UPDATE VIEW VIEW PUSHED PREDICATE WINDOW
Optimize SQL
Create Optimize SQL Sessions Open Optimizer SQL Sessions Rewrite SQL Generate Execution Plan Alternatives
Optimize Indexes Batch Optimize SQL Scan SQL Inspect SGA Analyze Impact Manage Plans Configure Options SQL Optimizer Tutorials About Us Legal Notices

Scan SQL

To set Scan SQL options

  1. Click in the main menu.

  2. Select Scan SQL

  3. Review the following for additional information:

    Automatically start extracting SQL when job is added

    Select to automatically start scanning Scan SQL jobs you create.

    Skip SQL with comments

    Select to ignore SQL statements found within comments when scanning a job.

    Note: Selecting this option also affects scanning performed by Batch Optimize SQL.

    Skip SQL that involves only SYS.DUAL table

    Select to ignore SQL statements that use only the SYS.DUAL table when scanning a job.

    Note: Selecting this option also affects scanning performed by Batch Optimize SQL.

    Whole word matching for the first SQL keyword

    Select to ignore SELECT, INSERT, UPDATE, or DELETE when these keywords are preceded by other characters (for example, "abcSELECT" or "123SELECT" or "?SELECT").

    Deselect (clear) to allow SQL Optimizer to extract the keywords listed above when preceded by other characters.

    Note: Selecting this option also affects scanning performed by Batch Optimize SQL.

    Number of characters skipped at the beginning of every line for all files

    Enter the number of characters to skip at the beginning of each line during scanning.

    Note: Selecting this option also affects scanning performed by Batch Optimize SQL.

    Skip end of line continuation character

    Click and select the continuation character to skip at the end of each line during scanning.

    Note: Selecting this option also affects scanning performed by Batch Optimize SQL.

 

Manage Plans

To set general Manage Plans options

  1. Click in the main menu.

  2. Select Manage Plans.

  3. Review the following for additional information:

    Show Manage Plans

    Select to display the Manage Plans tab in the main window.

 

SQL Optimizer Tutorials

Tutorial: Optimize SQL (SQL Rewrite)

Using SQL Rewrite mode in Optimize SQL consists of two steps. In the first step, SQL Optimizer generates semantically equivalent alternatives with unique execution plans for your original SQL statement. An Oracle cost estimate displays for each alternative generated. In the second step, SQL Optimizer executes the alternatives to test each statement's performance. This provides execution times and run time statistics that allow you to find the best SQL statement for your database environment.

Tip: The Oracle cost only provides an estimate of resource usage to execute a SQL statement. Since statements with higher cost may perform better, you should test alternatives generated to determine the best statements for your database environment.

Step 1: Optimize the SQL Statement

  1. Select the Optimize SQL tab in the main window.

  2. Select SQL Rewrite from the Optimize SQL start page.

    Note: If the start page does not display, click the arrow beside and select New SQL Rewrite Session.

  3. Enter a SQL statement in the Alternative Details pane.

  4. Click to retrieve the execution plan for your SQL statement.The Select Connection and Schema window displays.

  5. Select a connection and schema to use.

  6. Click to optimize the SQL statement.

  7. Click after SQL Optimizer completes the SQL rewrite process to compare your original SQL statement with the alternatives generated.

Step 2: Test Alternative SQL Statements

To test the alternatives SQL Optimizer generates, you can test run one or more selected alternatives to obtain actual execution statistics. This function does not affect network traffic since SQL Optimizer can provide these statistics without having to retrieve result sets from the database server. Additionally, data consistency is maintained when using SELECT, SELECT INTO, INSERT, DELETE, and UPDATE statements because these statements run in a transaction that is rolled back after execution.

To test a SQL statement alternative

  1. Click after you finish comparing your original SQL statement with the alternatives generated.
  2. Click the drop-down arrow beside and select Test Run - All to execute all SQL alternatives.

  3. The Test Run Settings dialog opens. Select criteria to apply to this test run. You can answer the questions on the Usage and Symptom page to allow SQL Optimizer to determine settings for you. Or you can click the Customize Test Run Settings link at the bottom of the page to manually specify test run settings.

    Tip: You can specify default values for some Test Run Settings options by clicking and selecting Optimize SQL | Test Run.

  4. Review the execution statistics in the Alternatives pane.

 

Related Topics

About Optimizing SQL (SQL Rewrite)

Optimize Original SQL Statement

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