Exam 11: Database Performance Tuning and Query Optimization

The must be set large enough to permit as many data requests to be serviced from cache as possible.

_________is evaluated based on client perspective.

A DBA determines the initial size of the data files that make up the database; however,as required,the data files can automatically expand in predefined increments known as .

The primary factor in determining the most efficient access plan is the I/O cost.

Working with data in the data cache is many times faster than working with data in the data files.

Good database performance is easy to evaluate.

Good database performance starts with good database design.

The DBMS the data and sends the result set back to the client.

When setting optimizer hints,instructs the optimizer to minimize the overall execution time,that is,to minimize the time it takes to return the total number of rows in the query result set.This hint is generally used for batch mode processes.

Automatic query optimization means that the:

Maximizing disk contention is one of the general recommendations for the physical storage of databases.

The process analyzes SQL queries and finds the most efficient way to access data.

All transaction management commands are processed during the parsing and execution phases of query processing.

is a measure of the likelihood that an index will be used in query processing.

When moving data from permanent storage to RAM,an I/O disk operation retrieves:

are ordered sets of values that are crucial in speeding up data access.

To work with data,a DBMS must retrieve the data from and place them in .

All factors must be checked to ensure that each system component operates at its optimum level and has sufficient resources to minimize the occurrence of bottlenecks.

RAID systems use a single disk to create storage volumes.

Indexes are very useful in small tables or tables with low sparsity.