.
Indexes are only used in special cases
Indexes are used to make table storage more efficient
Indexes rarely make a difference in SQL performance
Indexes exist solely to improve query speed.
Buffer hit ratio
Library cache hit ratio
Full-table scans
Buffer busy waits
They indicate an optimized execution plan.
They may be able to be tuned to use an index
The full-table scan should be normalized from the database design
A full-table scan is always sub-optimal.
Add blocks to the SGA buffer pool
Created a clustered table
Create tables with redundant columns from other tables
Run parallel query against the table
Removal of data redundancy
The introduction of data redundancy
The introduction of non-first normal form relations
The introduction of SQL*Plus
De-normalization of the logical tables
Eliminating full-table scans from SQL queries
Moving Oracle data files from hot disks onto cool disks
Adding additional storage to the SGA shared pool
The number of CPUs on the server
The degree of parallelism on the tables
The quality of the SQL optimization
The use of bitmap indexes
Logical design tuning
Physical design tuning
SGA tuning
SQL tuning
Independence of table relationships
High speed of SQL
Powerful GUI front-end
Easy to install and use
A part of SGA memory is used to store ASH data as rolling buffer.
All ASH data in memory are flushed to disk by MMNL process whenever the buffer is full.
All ASH data in memory are flushed to disk by MMON in every 3 seconds.
None of the above
When physical I/Os are performed to read from data files
When the database writer process writes to the SYSTEM tablespace
When the server process writes sort data to the temporary tablespace
When the database writer process writes undo data to the undo tablespace
It detects changes in SQL execution plans.
It produces results that can be used to create the SQL plan baseline.
It generates recommendations to run SQL Tuning Advisor to tune regressed SQL statements.
All of the above
Very high cache-hit ratio
Increasing number of free buffer waits
increasing number of buffer busy waits
Waits on latch: cache buffers chains event
For a database with lower recovery (MTTR) overhead
For a database in which the applications primarily perform read operations and predominantly sequential I/O is performed
For a database in which performance is the primary goal of the database because applications are demanding in terms of I/O operations
None of the above
Because the ROWID changes for these rows
Because these rows make existing indexes invalid
Because it is not possible to use indexes to retrieve these rows
Because retrieving these rows requires more than one data block to be accessed
Resource limit
memory statistics
Optimizer execution plans
All of the above
Frequent logfile switches are occurring.
Redo is generated faster than LGWR can write it out.
Frequent commits or rollbacks are taking place in the application.
Frequent incremental checkpoints are taking place in the database.
It is the sum of the CPU time of all nonidle sessions.
It is the sum of wait time and the CPU time of all nonidle sessions.
It is the time spent in processing the input/output (I/O) request by users.
It is the difference between the wait time and the CPU time of all nonidle sessions.
Trace for the statement would be created without displaying the query output.
It generates a report on the execution path used by the SQL optimizer and the statement execution statistics.
Above A and B
It generates only the statement execution statistics without executing the query.