SQL Performance Optimization with Db2

Questions and Answers

How does a schema benefit multiple applications accessing a single database?

It merges data from different applications automatically

It allows data to be stored in different locations

It provides a performance boost for queries

It prevents namespace collisions among objects (correct)

What distinguishes a schema from other database objects?

Schemas can only contain tables

A schema itself is classified as a database object (correct)

Schemas are always temporary in nature

Schemas can only group functions and triggers

Which scenario best illustrates the use of schemas in relational databases?

A schema merging all objects into a single location

A schema that only interacts with user interfaces of applications

A schema comprising only duplicate data for redundancy

A schema storing personal data separately from transactional data within the same database (correct)

What is the primary function of the Change Definition Language (CDL) generated by BMC AMI Command Center for Db2?

To specify the changes needed to make two schema structures identical. Signup and view all the answers

Which statement about the reports generated during schema comparison is correct?

They list all objects that need to be created, altered, or dropped. Signup and view all the answers

Which input is necessary to create a schema compare view in BMC AMI Command Center for Db2?

Two schemas or sets of Db2 objects for comparison. Signup and view all the answers

What does the overview by statement type report visually display?

A breakdown of objects requiring alterations, creations, or deletions. Signup and view all the answers

What limitation exists regarding DDL statements in schema comparisons?

They are not applicable for schema comparison. Signup and view all the answers

How can a user interact with the overview report's pie chart?

They can click on a pie section to see related CDL statements. Signup and view all the answers

What does the column chart in the schema comparison reports represent?

The number of create, alter, and drop statements needed. Signup and view all the answers

What is a necessary input for performing a schema comparison in the BMC AMI Command Center?

A set of objects representing the existing schema. Signup and view all the answers

What is the role of the scratchpad editor in relation to the Change Definition Language?

It allows users to edit the CDL before applying changes. Signup and view all the answers

What type of reports can be switched between using the report selector drop-down?

Statement-type and object-type reports. Signup and view all the answers

Study Notes

SQL Performance Issues

Inefficient SQL statements can significantly impact application throughput and response time.
Minor application or Db2 data structure changes can greatly affect performance and availability.

BMC AMI SQL Explorer for Db2

It is an SQL analysis tool used to identify performance problems caused by inefficient SQL statements.
It helps application developers correct performance issues before they reach production.
It enables DBAs to identify and manage performance impacts resulting from data structure changes before implementing them in production.
It helps resolve problems that are already in production.

SQL Explorer: Addressing Common Problems

Plan table information is cryptic and requires expert knowledge of the Relational Database Management System (RDBMS), which SQL Explorer simplifies with customizable expert rules.

Expert Rules and Customization

Expert rules can be tailored for specific environments or technical audiences by DBAs and performance experts.
Customization options include setting or changing thresholds and issuing warnings on keywords to be avoided.

Application Development and Performance Tuning

Application developers can use SQL Explorer to parse and check SQL code against expert rules.
SQLX edit macro enables quick, online explanation or execution of a single SQL statement from a TSO edit session.
Developers can perform application-specific tuning and check their SQL in the development phase.

Impact Analysis and Database Comparison

SQL Explorer offers impact analysis to see the effects of anticipated changes before making them.
The tool can compare database request module (DBRM) libraries to Db2 catalogs, reducing testing time and preventing the need to roll back the Db2 catalog.

Integration and Reporting

SQL Explorer integrates with BMC AMI Catalog Manager for Db2, enabling automatic Explain jobs on binds or rebinds.
The tool offers online and batch reporting capabilities for planning and impact analysis.

Recommendations and Expert Knowledge

SQL Explorer provides a source of expert knowledge for DBAs, application developers, and performance experts.
The tool helps maintain expert knowledge by analyzing SQL and detecting statements that should be avoided in specific circumstances.

Relational Database Schemas

Objects in relational databases are organized into sets known as schemas.
Schemas provide a logical grouping of database objects, aiding in organization and management.
Multiple applications can use the same database without namespace collisions due to schemas.

Contents of a Schema

A schema can encompass a variety of objects, including:
- Tables: Store data in rows and columns.
- Views: Virtual tables presenting data from one or more tables.
- Nicknames: Aliases for remote database objects.
- Triggers: Automatic actions executed in response to events on a table.
- Functions: Stored procedures that perform operations and return values.
- Packages: Collections of related procedures and functions.

Schema Characteristics

A schema is considered a database object itself, representing a structured way to manage database resources.

Schema Comparison Process

Comparing schemas aids in recording changes made to local or remote subsystems.
Helps determine which changes between two subsystems should be migrated.
Involves generating and viewing reports to identify structural differences.

Reporting in BMC AMI Command Center for Db2

Generates reports listing objects to be created, altered, or dropped for schema alignment.
Can compare two sets of data structures within a Db2 catalog or a DDL file.
Produces Data Definition Language (DDL) and Data Manipulation Language (DML) statements, although DDL statements are not applicable for schema comparison.

Change Definition Language (CDL)

BMC AMI Command Center for Db2 creates Change Definition Language (CDL) for defining necessary changes for schema alignment.
CDL can be saved to a data set and edited in a scratchpad editor.

Input Requirements for Schema Comparison

Primary input includes the schema or set of Db2 objects with desired structure definitions needing changes.
The preferred structure schema serves as the second input for comparison and guidance for modifications.

Overview Reports and Visualizations

Overview by statement type report includes a pie chart detailing object breakdown for selected statement types (alter, create, drop).
A column chart shows the count of required create, alter, and drop statements for structure alignment.
Color legends in the pie chart correspond to object types, enabling easy identification.

Interactive Reporting Features

Selecting a pie chart section reveals a list of all CDL statements for that specific object type.
Users can switch between statement-type and object-type reports using a report selector drop-down for customized views.

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Description

Learn how to identify and correct inefficient SQL statements that impact application performance and availability using BMC AMI SQL Explorer for Db2.