The Abstract Plan Manager provides a window for you to easily view, create, delete and modify your abstract plan groups.
In Adaptive Server version 15 and above, the abstract plan enables you to influence the optimization of a SQL statement without having to modify the SQL statement syntax. If you cannot change the source code that contains your SQL statement, you can use the abstract plan to force Adaptive Server to use a specific query plan for a SQL statement. This is particularly useful if you have third party applications where you do not have access to the source code.
Another use of the abstract plan is to protect the performance from changes to the database. When changes are made to a database, Adaptive Server may choose a different query plan for a SQL statement as a result of the changes. The abstract plans provide a means for system administrators and performance tuners to protect the overall performance of a SQL statement from these changes since the abstract plan will cause Adaptive Server to always choose the same query plan.
In the SQL Optimizer window, you can find alternate abstract plans in one of two ways while you are optimizing a SQL statement. First, you can optimize to find only the compatible alternative abstract plans. Second, you can optimize to find the semantically equivalent SQL statements with alternative query plans and then choose the ones with compatible alternative abstract plans.
Abstract Plan Compatibility with Original SQL
Open the Abstract Plan Manager
Import an Abstract Plan for each User
Abstract plans are saved to an abstract plan group. The group has the following elements associated with it:
When you save an abstract plan, you specify the database, group and user. This means that you can have a different abstract plan for different users. It enables SQL optimization to be based on the user’s individual activities.
Here is an example of where you might want to have a different abstract plan for different users. In this example, the column emp_sex is indexed.
select * from employee where emp_sex=:var_sex
If 90% employees are male, then the SQL statement to retrieve the records where the employees are male should not be indexed for the best results.
But the SQL statement to retrieve the 10% of the employees who are female should be indexed.
For Group A users, who always select "male" employees, the Abstract Plan should do full table scan. For Group B users, who always select "female" employees, the Abstract Plan should use an index scan.
If you use the default group of ap_stdin, you can set Adaptive Server to use this group server-wide. You must save each abstract plan that you want to use system-wide in this group.
You can set up Adaptive Server to use different abstract plans for the same SQL statement from different applications. In this case, you create a different group for each application. For each user that you want to use a specific abstract plan, you must save that abstract plan in the group.
Abstract Plan Compatibility with Original SQL
Open the Abstract Plan Manager
Abstract Plan Manager Overview
Import an Abstract Plan for each User
Saving the abstract plan for a SQL statement preserves how the SQL statement is executed. Therefore, when changes occur in the database environment, the query plan used to execute the SQL statement remains constant.
One major advantage of saving the abstract plan is that you can optimize the SQL statement without altering the SQL text. This is an ideal solution for when you do not have the source code from a vendor but want to improve the performance of the database application. The saving of the abstract plan can be very useful when you are considering making changes to the configuration parameters or you are migrating to another version of Adaptive Server and you want to preserve the current performance of SQL statements that are critical to the performance of your applications.
These database environment changes may include:
Parallel degree
Table partitioning
Indexing
Database software upgrades
Changes in data columns
You can save an abstract plan from the following modules:
| To save in... | See: |
|
SQL Optimizer |
Save Abstract Plan |
|
SQL Scanner |
Save Abstract Plan. |
|
Index Impact Analyzer |
Right Pane for SQL Statements |
|
Configuration Analyzer |
Right Pane for SQL Statement |
|
Migration Analyzer |
Right Pane for SQL Statement |
|
SQL Repository |
SQL Repository Window |
Abstract Plan Compatibility with Original SQL
Open the Abstract Plan Manager
© 2024 Quest Software Inc. ALL RIGHTS RESERVED. Termini di utilizzo Privacy Cookie Preference Center
