Below is a list of available functions within the Migration Analyzer window.
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Add Folder |
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View Menu |
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
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