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Top 100 Oracle Performance Tuning Interview Questions and Answers

Top 100 Oracle Performance Tuning Interview Questions and Answers

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Question 1: What is Oracle Performance Tuning?

Answer: Oracle Performance Tuning involves optimizing the performance of Oracle databases for efficient and faster query execution.

Official Reference: Oracle Performance Tuning


Question 2: What are the key areas to focus on for Oracle Performance Tuning?

Answer: Key areas include SQL optimization, indexing strategies, memory management, and I/O optimization.

Official Reference: Oracle Performance Tuning Areas


Question 3: How can you identify poorly performing SQL queries?

Answer: Use tools like Oracle’s AWR reports and SQL trace to identify and analyze slow queries.

Code Snippet:

SELECT sql_id, sql_text
FROM v$sql
WHERE elapsed_time/execution_count > threshold;

Official Reference: Identifying Poorly Performing SQL


Question 4: What is an Execution Plan in Oracle?

Answer: An Execution Plan is a set of steps Oracle uses to execute a SQL statement.

Code Snippet:

EXPLAIN PLAN FOR
SELECT * FROM employees WHERE department_id = 10;

Official Reference: Oracle Execution Plans


Question 5: How can you improve the performance of a slow SQL query?

Answer: Consider indexing columns used in WHERE clauses, optimizing joins, and using hints to guide the optimizer.

Code Snippet (Using a Hint):

SELECT /*+ INDEX(employees idx_department_id) */ *
FROM employees WHERE department_id = 10;

Official Reference: Improving SQL Query Performance


Question 6: What is the purpose of an index in Oracle?

Answer: An index in Oracle speeds up data retrieval by providing a fast path to rows in a table.

Code Snippet (Creating an Index):

CREATE INDEX idx_department_id ON employees(department_id);

Official Reference: Oracle Indexes


Question 7: How can you monitor and analyze the performance of an Oracle database?

Answer: Use Oracle’s Automatic Workload Repository (AWR) reports and Automatic Database Diagnostic Monitor (ADDM) for performance analysis.

Code Snippet (Generating AWR Report):

SELECT * FROM TABLE(DBMS_WORKLOAD_REPOSITORY.AWR_REPORT_HTML(123, 456));

Official Reference: Oracle Performance Monitoring


Question 8: What is the role of caching in Oracle Performance Tuning?

Answer: Caching stores frequently accessed data in memory for faster retrieval, reducing disk I/O.

Official Reference: Oracle Caching


Question 9: How can you optimize I/O performance in Oracle?

Answer: Use RAID configurations, separate data files and redo logs, and utilize asynchronous I/O.

Official Reference: Oracle I/O Optimization


Question 10: What is the purpose of partitioning in Oracle?

Answer: Partitioning divides large tables into smaller, more manageable pieces for improved performance and maintenance.

Code Snippet (Creating a Partitioned Table):

CREATE TABLE sales
   (sale_date DATE, product_id NUMBER, qty NUMBER)
PARTITION BY RANGE (sale_date)
   (PARTITION sales_jan VALUES LESS THAN (TO_DATE('01-FEB-2023','DD-MON-YYYY')));

Official Reference: Oracle Partitioning


Question 11: What is a stored outline in Oracle?

Answer: A stored outline is a set of optimizer hints that guide the optimizer’s behavior for a specific SQL statement.

Code Snippet (Creating a Stored Outline):

CREATE OUTLINE outline_name ON sql_text;

Official Reference: Oracle Stored Outlines


Question 12: How can you identify and optimize long-running queries?

Answer: Use Oracle’s SQL Trace or SQL Developer’s Tuning Advisor to identify and optimize queries.

Code Snippet (Enabling SQL Trace):

ALTER SESSION SET sql_trace = true;

Official Reference: Oracle SQL Trace


Question 13: What is the purpose of the Oracle Optimizer?

Answer: The Oracle Optimizer is a component that determines the most efficient way to execute a SQL statement.

Official Reference: Oracle Optimizer


Question 14: How can you use hints to influence the Oracle Optimizer?

Answer: Hints are comments in SQL statements that instruct the optimizer on how to execute the statement.

Code Snippet (Using Hints):

SELECT /*+ INDEX(employees idx_department_id) */ *
FROM employees WHERE department_id = 10;

Official Reference: Oracle Hints


Question 15: What is Oracle’s Automatic Database Diagnostic Monitor (ADDM)?

Answer: ADDM is a self-diagnostic engine that identifies performance issues in an Oracle database and provides recommendations.

Official Reference: Oracle ADDM


Question 16: How can you optimize the memory configuration in Oracle?

Answer: Adjust parameters like SGA_TARGET and PGA_AGGREGATE_TARGET to optimize memory allocation for the database.

Code Snippet (Setting SGA Target):

ALTER SYSTEM SET SGA_TARGET=2G;

Official Reference: Oracle Memory Configuration


Question 17: What is the purpose of the Oracle Buffer Cache?

Answer: The Buffer Cache is a portion of the SGA that holds copies of data blocks for quick access.

Official Reference: Oracle Buffer Cache


Question 18: How can you use parallel processing for query optimization?

Answer: Use the PARALLEL hint to enable parallel processing for a specific SQL statement.

Code Snippet (Using Parallel Hint):

SELECT /*+ PARALLEL(employees, 4) */ *
FROM employees;

Official Reference: Oracle Parallel Processing


Question 19: What is the role of the Oracle Optimizer Statistics?

Answer: Optimizer Statistics provide information about the data distribution in tables and indexes, helping the optimizer make better decisions.

Official Reference: Oracle Optimizer Statistics


Question 20: How can you use partitioning for performance optimization?

Answer: Partitioning can improve performance by allowing operations on smaller, more manageable pieces of data.

Code Snippet (Creating a Partitioned Table):

CREATE TABLE sales
   (sale_date DATE, product_id NUMBER, qty NUMBER)
PARTITION BY RANGE (sale_date)
   (PARTITION sales_jan VALUES LESS THAN (TO_DATE('01-FEB-2023','DD-MON-YYYY')));

Official Reference: Oracle Partitioning


Question 21: What is the purpose of an Oracle Index?

Answer: An Oracle Index is a data structure that improves the speed of data retrieval operations on a table.

Code Snippet (Creating an Index):

CREATE INDEX index_name ON table_name(column_name);

Official Reference: Oracle Indexes


Question 22: How can you identify and resolve I/O performance issues?

Answer: Monitor disk I/O statistics using tools like Oracle Enterprise Manager or STATSPACK. Consider redistributing I/O across disks or using faster storage solutions.

Official Reference: Oracle I/O Performance


Question 23: What are Oracle Wait Events?

Answer: Wait events are statistics that indicate the time spent by a session waiting for a specific event, like I/O or locks.

Code Snippet (Checking Wait Events):

SELECT event, total_waits, time_waited
FROM v$session_event
WHERE sid = <session_id>;

Official Reference: Oracle Wait Events


Question 24: How can you optimize SQL queries with subqueries?

Answer: Use subqueries to break down complex queries into simpler, more manageable parts. Ensure the subquery returns a small result set.

Code Snippet (Using a Subquery):

SELECT column1
FROM table1
WHERE column2 IN (SELECT column2 FROM table2 WHERE condition);

Official Reference: Oracle Subqueries


Question 25: What is the purpose of Oracle Materialized Views?

Answer: Materialized Views are precomputed views that store the results of a query, improving query performance.

Code Snippet (Creating a Materialized View):

CREATE MATERIALIZED VIEW mv_name
AS SELECT column1, column2 FROM table_name WHERE condition;

Official Reference: Oracle Materialized Views


Question 26: How can you optimize database connections in Oracle?

Answer: Use connection pooling to reduce the overhead of establishing new connections. Adjust parameters like PROCESSES and SESSIONS to handle the expected number of connections.

Official Reference: Oracle Connection Pooling


Question 27: What is the role of Oracle AWR Reports?

Answer: AWR (Automatic Workload Repository) Reports provide a detailed snapshot of database performance over a specified time period.

Official Reference: Oracle AWR Reports


Question 28: How can you monitor and optimize temporary space usage?

Answer: Use the TEMP tablespace for sorting and joining operations. Monitor TEMP space usage and adjust its size accordingly.

Official Reference: Oracle Temporary Tablespaces


Question 29: What is the purpose of Oracle SQL Plan Baselines?

Answer: SQL Plan Baselines capture efficient execution plans for SQL statements and ensure they are used consistently.

Official Reference: Oracle SQL Plan Baselines


Question 30: How can you optimize performance for large datasets in Oracle?

Answer: Use techniques like partitioning, parallel processing, and proper indexing to handle large datasets efficiently.

Official Reference: Oracle Performance Tuning for Large Datasets


Question 31: What is the purpose of the Oracle Query Optimizer?

Answer: The Oracle Query Optimizer analyzes SQL statements and chooses the most efficient execution plan to retrieve data.

Official Reference: Oracle Query Optimizer


Question 32: How can you identify and address high CPU usage in an Oracle database?

Answer: Monitor CPU usage with tools like top or Oracle Enterprise Manager. Identify CPU-intensive SQL statements and optimize them.

Official Reference: Oracle CPU Usage


Question 33: What is the purpose of Oracle Database Statistics?

Answer: Database statistics provide metadata about tables, indexes, and columns, enabling the Query Optimizer to generate efficient execution plans.

Code Snippet (Gathering Statistics):

BEGIN
   DBMS_STATS.GATHER_TABLE_STATS('schema_name', 'table_name');
END;

Official Reference: Oracle Database Statistics


Question 34: How can you monitor and optimize memory usage in an Oracle database?

Answer: Use the Oracle Memory Advisor to recommend optimal memory settings. Monitor the SGA and PGA usage regularly.

Official Reference: Oracle Memory Advisor


Question 35: What are Oracle Bind Variables and why are they important for performance?

Answer: Bind variables hold values that can be reused in multiple executions of a SQL statement, reducing parse overhead and improving performance.

Code Snippet (Using Bind Variables):

DECLARE
   v_name VARCHAR2(50) := 'John Doe';
BEGIN
   SELECT * FROM employees WHERE employee_name = v_name;
END;

Official Reference: Oracle Bind Variables


Question 36: How can you optimize the performance of Oracle PL/SQL code?

Answer: Use efficient SQL queries, minimize context switches between PL/SQL and SQL, and optimize loops and collections.

Official Reference: Oracle PL/SQL Optimization


Question 37: What is the purpose of Oracle Automatic Segment Space Management?

Answer: Automatic Segment Space Management eliminates the need to specify storage parameters for tables and indexes, simplifying space management.

Official Reference: Oracle Segment Space Management


Question 38: How can you optimize performance for Oracle parallel query operations?

Answer: Use parallel hints or set the PARALLEL attribute for tables or indexes. Ensure there are enough parallel execution servers.

Official Reference: Oracle Parallel Query Optimization


Question 39: What are the benefits of partitioning in Oracle databases?

Answer: Partitioning improves query performance, simplifies data management, and enhances availability and maintainability.

Official Reference: Oracle Partitioning


Question 40: How can you identify and optimize SQL statements with high buffer gets?

Answer: Use tools like Oracle Enterprise Manager to identify high-buffer-get SQL statements. Optimize them by adding appropriate indexes.

Official Reference: Oracle Buffer Gets


Question 41: What is the purpose of Oracle AWR (Automatic Workload Repository) reports?

Answer: AWR reports provide detailed performance information about an Oracle database, helping in diagnosing and resolving performance issues.

Code Snippet (Generating AWR Report):

-- Connect as SYSDBA
@?/rdbms/admin/awrrpt.sql

Official Reference: Oracle AWR Reports


Question 42: How can you identify and optimize SQL statements with high disk reads?

Answer: Use tools like Oracle Enterprise Manager to identify high-disk-read SQL statements. Optimize them by adding appropriate indexes or rewriting the query.

Official Reference: Oracle Disk Reads


Question 43: What is Oracle’s Optimizer Mode and how does it affect query execution plans?

Answer: The Optimizer Mode influences the behavior of the Oracle Query Optimizer. Modes like ALL_ROWS prioritize fast query response, while FIRST_ROWS aims for fast retrieval of the first few rows.

Code Snippet (Setting Optimizer Mode):

ALTER SESSION SET OPTIMIZER_MODE = FIRST_ROWS;

Official Reference: Oracle Optimizer Modes


Question 44: How can you identify and optimize SQL statements with high wait events?

Answer: Use Oracle’s Wait Interface and tools like AWR or Statspack reports to identify high-wait-event SQL statements. Optimize by reducing the wait events.

Official Reference: Oracle Wait Events


Question 45: What is the purpose of Oracle Data Pump and how can it be used for performance tuning?

Answer: Oracle Data Pump is used for high-speed data and metadata movement. It can be used to reorganize and optimize data for better performance.

Code Snippet (Using Data Pump):

-- Export
expdp username/password@dbname tables=table_name directory=dir dumpfile=dump.dmp

-- Import
impdp username/password@dbname tables=table_name directory=dir dumpfile=dump.dmp

Official Reference: Oracle Data Pump


Question 46: How can you optimize the performance of Oracle RAC (Real Application Clusters)?

Answer: Ensure balanced workload across RAC instances, use services for workload management, and implement proper cache fusion and interconnect tuning.

Official Reference: Oracle RAC Optimization


Question 47: What is Oracle’s Automatic Shared Memory Management (ASMM)?

Answer: ASMM dynamically manages the sizes of the SGA components, optimizing memory usage based on workload.

Code Snippet (Enabling ASMM):

ALTER SYSTEM SET MEMORY_TARGET = value SCOPE=SPFILE;

Official Reference: Oracle ASMM


Question 48: How can you use Oracle Index Monitoring to improve performance?

Answer: Index Monitoring helps identify unused and underutilized indexes. It allows for more efficient use of storage and resources.

Code Snippet (Monitoring Index):

ALTER INDEX index_name MONITORING USAGE;

Official Reference: Oracle Index Monitoring


Question 49: What are the benefits of using Oracle Exadata for performance tuning?

Answer: Oracle Exadata provides a high-performance and scalable platform for running Oracle databases. It leverages hardware optimizations to accelerate query performance.

Official Reference: Oracle Exadata


Question 50: How can you optimize performance for Oracle OLTP (Online Transaction Processing) systems?

Answer: Use techniques like partitioning, indexing, and optimizing SQL queries to handle high transaction volumes efficiently.

Official Reference: Oracle OLTP Optimization


Question 51: What is the purpose of the Oracle SQL Tuning Advisor?

Answer: The SQL Tuning Advisor analyzes high-load SQL statements and provides recommendations to improve their performance.

Code Snippet (Using SQL Tuning Advisor):

-- Create a SQL tuning task
DECLARE
  my_task_name VARCHAR2(30) := 'my_sql_tuning_task';
BEGIN
  DBMS_SQLTUNE.CREATE_TUNING_TASK (
    sql_tune_task_name => my_task_name,
    sql_id => 'your_sql_id',
    scope => DBMS_SQLTUNE.SCOPE_COMPREHENSIVE,
    time_limit => 60,
    task_name => 'tune_task'
  );
END;
/

Official Reference: Oracle SQL Tuning Advisor


Question 52: What are Oracle SQL Profiles and how can they be used for performance tuning?

Answer: SQL Profiles are used to store and apply optimizer hints for specific SQL statements, improving their execution plans.

Code Snippet (Creating a SQL Profile):

-- Create a SQL profile
DECLARE
  profile_name VARCHAR2(30) := 'my_sql_profile';
BEGIN
  DBMS_SQLTUNE.CREATE_PROFILE (
    sql_text => 'SELECT * FROM my_table WHERE column_name = :bind_variable',
    name => profile_name,
    category => 'DEFAULT',
    force_match => TRUE
  );
END;
/

Official Reference: Oracle SQL Profiles


Question 53: How can you optimize the performance of Oracle PL/SQL code?

Answer: Optimize PL/SQL code by minimizing context switches between SQL and PL/SQL, using bulk operations, and avoiding unnecessary iterations.

Official Reference: Oracle PL/SQL Optimization


Question 54: What is the purpose of Oracle SQL Plan Baselines?

Answer: SQL Plan Baselines capture and use the optimal execution plans for SQL statements, preventing performance regressions.

Code Snippet (Creating a SQL Plan Baseline):

-- Create a SQL Plan Baseline
DECLARE
  sql_handle VARCHAR2(30) := 'sql_handle_value';
BEGIN
  DBMS_SPM.LOAD_PLANS_FROM_CURSOR_CACHE (
    sql_id => 'your_sql_id',
    plan_hash_value => NULL,
    sql_handle => sql_handle,
    fixed => 'YES'
  );
END;
/

Official Reference: Oracle SQL Plan Baselines


Question 55: How can you monitor the performance of Oracle database using STATSPACK?

Answer: STATSPACK provides a detailed performance snapshot of an Oracle database, including wait events, SQL statements, and more.

Code Snippet (Generating STATSPACK Report):

-- Connect as SYSDBA
@$ORACLE_HOME/rdbms/admin/spcreate.sql
@$ORACLE_HOME/rdbms/admin/sppurge.sql
@$ORACLE_HOME/rdbms/admin/spcpkg.sql
@$ORACLE_HOME/sqlplus/admin/pupbld.sql

Official Reference: Oracle STATSPACK


Question 56: How can you use Oracle’s Real-Time SQL Monitoring for performance optimization?

Answer: Real-Time SQL Monitoring provides detailed information about the execution of SQL statements, allowing for immediate performance tuning.

Code Snippet (Monitoring SQL Statement):

-- Enable Real-Time SQL Monitoring
ALTER SESSION SET SQL_MONITOR = 'ALL';

Official Reference: Oracle Real-Time SQL Monitoring


Question 57: What is the purpose of Oracle Database Resource Manager?

Answer: Resource Manager allocates resources like CPU and memory to different user sessions and groups, ensuring fair and efficient resource utilization.

Code Snippet (Setting Resource Plan):

-- Create a Resource Plan
BEGIN
  DBMS_RESOURCE_MANAGER.CREATE_PLAN (
    plan => 'my_resource_plan',
    comment => 'My Resource Plan'
  );
END;
/

Official Reference: Oracle Resource Manager


Question 58: How can you use Oracle’s Automatic SQL Tuning for performance optimization?

Answer: Automatic SQL Tuning identifies and optimizes high-load SQL statements, improving their execution plans.

Official Reference: Oracle Automatic SQL Tuning


Question 59: What is Oracle Database Automatic Storage Management (ASM) and how does it contribute to performance tuning?

Answer: Oracle ASM is a volume manager and file system specifically designed for Oracle database files. It simplifies storage administration, improves database performance, and reduces I/O contention.

Code Snippet (Creating Disk Group in ASM):

-- Create a Disk Group
CREATE DISKGROUP data
  NORMAL REDUNDANCY
  FAILGROUP controller1 DISK
    '/dev/sd1' NAME data1,
  FAILGROUP controller2 DISK
    '/dev/sd2' NAME data2;

Official Reference: Oracle ASM Documentation


Question 60: How can you use Oracle AWR (Automatic Workload Repository) for performance tuning?

Answer: AWR collects and maintains performance statistics for the database and provides detailed reports for analysis.

Code Snippet (Generating AWR Report):

-- Connect as SYSDBA
@$ORACLE_HOME/rdbms/admin/awrrpt.sql

Official Reference: Oracle AWR


Question 61: What is the purpose of Oracle Database Performance Analyzer (DBMS_PGA)?

Answer: DBMS_PGA helps identify performance bottlenecks by analyzing SQL statements and providing recommendations.

Code Snippet (Using DBMS_PGA):

-- Analyze SQL Statement
BEGIN
  DBMS_PGA.ANALYZE_SQL (
    sql_text => 'SELECT * FROM my_table WHERE column_name = :bind_variable'
  );
END;
/

Official Reference: Oracle DBMS_PGA


Question 62: How can you use Oracle SQL Performance Analyzer (SPA) for performance tuning?

Answer: SPA compares the performance of SQL statements before and after a change, helping evaluate the impact.

Code Snippet (Using SPA):

-- Create a SQL Tuning Set
DECLARE
  sts_name VARCHAR2(30) := 'my_sql_tuning_set';
BEGIN
  DBMS_SQLTUNE.CREATE_SQLSET (
    sqlset_name => sts_name,
    description => 'My SQL Tuning Set'
  );
END;
/

Official Reference: Oracle SQL Performance Analyzer


Question 63: How can you use Oracle Indexes for performance optimization?

Answer: Indexes speed up data retrieval by providing a fast access path to rows in a table.

Code Snippet (Creating an Index):

-- Create an Index
CREATE INDEX my_index ON my_table (column_name);

Official Reference: Oracle Indexes


Question 64: What is the purpose of Oracle Partitioning for performance tuning?

Answer: Partitioning divides a large table into smaller, more manageable pieces, improving query performance.

Code Snippet (Creating a Partitioned Table):

-- Create a Partitioned Table
CREATE TABLE my_partitioned_table (
  id NUMBER,
  name VARCHAR2(30)
)
PARTITION BY RANGE (id) (
  PARTITION p1 VALUES LESS THAN (1000),
  PARTITION p2 VALUES LESS THAN (2000),
  PARTITION p3 VALUES LESS THAN (MAXVALUE)
);

Official Reference: Oracle Partitioning


Question 65: How can you use Oracle Materialized Views for performance optimization?

Answer: Materialized Views store precomputed results of a query, improving query response time.

Code Snippet (Creating a Materialized View):

-- Create a Materialized View
CREATE MATERIALIZED VIEW my_mv
AS
SELECT * FROM my_table;

Official Reference: Oracle Materialized Views


Question 66: What is the purpose of Oracle Database In-Memory Option for performance tuning?

Answer: In-Memory Option speeds up analytic queries by storing portions of the database in memory.

Official Reference: Oracle In-Memory Option


Question 67: How can you use Oracle Parallel Execution for performance optimization?

Answer: Parallel Execution improves query performance by dividing a task among multiple processes.

Code Snippet (Using Parallel Hints):

-- Use Parallel Hint
SELECT /*+ parallel(my_table, 4) */ * FROM my_table;

Official Reference: Oracle Parallel Execution


Question 68: What is the purpose of Oracle Database In-Memory Aggregation for performance tuning?

Answer: In-Memory Aggregation speeds up analytic queries by storing summarized data in memory.

Official Reference: Oracle In-Memory Aggregation


Question 69: How can you use Oracle Database Buffer Cache for performance optimization?

Answer: The Buffer Cache stores data blocks in memory to reduce physical I/O.

Code Snippet (Monitoring Buffer Cache Hit Ratio):

-- Check Buffer Cache Hit Ratio
SELECT (1 - (phy.value / (

cur.value + con.value))) * 100 "Buffer Cache Hit Ratio"
FROM v$sysstat cur, v$sysstat con, v$sysstat phy
WHERE cur.name = 'db block gets'
  AND con.name = 'consistent gets'
  AND phy.name = 'physical reads';

Official Reference: Oracle Database Buffer Cache


Question 70: How can you use Oracle Database Flash Cache for performance optimization?

Answer: Flash Cache extends the database buffer cache to solid-state drives (SSDs), improving I/O performance.

Official Reference: Oracle Flash Cache


Question 71: What is the purpose of Oracle Automatic Database Diagnostic Monitor (ADDM) in performance tuning?

Answer: ADDM analyzes performance data and provides recommendations to improve database performance.

Official Reference: Oracle ADDM


Question 72: How can you use Oracle SQL Plan Management for performance optimization?

Answer: SQL Plan Management ensures that a SQL statement uses the best execution plan.

Code Snippet (Creating SQL Plan Baseline):

-- Create SQL Plan Baseline
BEGIN
  DBMS_SPM.CREATE_SQL_PLAN_BASELINE (
    sql_handle => 'sql_handle_value',
    plan_name => 'plan_name_value',
    plan_source => 'plan_source_value'
  );
END;
/

Official Reference: Oracle SQL Plan Management


Question 73: What is the purpose of Oracle Database Resource Manager in performance tuning?

Answer: Resource Manager allocates system resources to different groups, ensuring optimal performance.

Code Snippet (Creating a Resource Plan):

-- Create Resource Plan
BEGIN
  DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
  DBMS_RESOURCE_MANAGER.CREATE_PLAN (
    plan => 'my_plan',
    comment => 'My Resource Plan'
  );
  DBMS_RESOURCE_MANAGER.CREATE_CONSUMER_GROUP (
    consumer_group => 'my_group',
    comment => 'My Consumer Group',
    mgmt_p1 => 'my_plan'
  );
  DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
END;
/

Official Reference: Oracle Resource Manager


Question 74: How can you use Oracle Database Replay for performance optimization?

Answer: Database Replay captures a workload and replays it on a test system for performance testing.

Official Reference: Oracle Database Replay


Question 75: What is the purpose of Oracle Database In-Memory Column Store for performance tuning?

Answer: Column Store stores data for specific columns in a compressed, in-memory format for faster retrieval.

Official Reference: Oracle In-Memory Column Store


Question 76: How can you use Oracle Database Automatic Storage Management (ASM) for performance optimization?

Answer: ASM simplifies storage management by managing disk groups and providing redundancy.

Official Reference: Oracle ASM


Question 77: What is the purpose of Oracle Database Result Cache for performance tuning?

Answer: Result Cache stores the results of SQL queries for fast retrieval.

Code Snippet (Using Result Cache):

-- Enable Result Cache for a Query
SELECT /*+ RESULT_CACHE */ * FROM my_table;

Official Reference: Oracle Result Cache


Question 78: How can you use Oracle Database SQL Tuning Advisor for performance optimization?

Answer: SQL Tuning Advisor analyzes high-load SQL statements and provides recommendations.

Code Snippet (Using SQL Tuning Advisor):

-- Run SQL Tuning Advisor
DECLARE
  task_name VARCHAR2(30) := 'my_tuning_task';
BEGIN
  DBMS_SQLTUNE.CREATE_TUNING_TASK (
    sql_id => 'sql_id_value',
    task_name => task_name,
    scope => DBMS_SQLTUNE.SCOPE_COMPREHENSIVE
  );
END;
/

Official Reference: Oracle SQL Tuning Advisor


Question 79: What is the purpose of Oracle Database Real Application Testing in performance tuning?

Answer: Real Application Testing allows testing of system changes before applying them in production.

Official Reference: Oracle Real Application Testing


Question 80: How can you use Oracle Database Data Pump for performance optimization?

Answer: Data Pump provides high-speed data and metadata movement between databases.

Code Snippet (Exporting a Table):

-- Export Table using Data Pump
expdp username/password@db tables=my_table directory=dp_dir dumpfile=my_table.dmp logfile=my_table.log

Official Reference: Oracle Data Pump


Question 81: What is Oracle Database Automatic PGA Memory Management and how can it be used for performance optimization?

Answer: PGA Memory Management automatically manages the memory allocated to the Program Global Area (PGA) for each server process.

Code Snippet (Enabling Automatic PGA Memory Management):

-- Enable Automatic PGA Memory Management
ALTER SYSTEM SET pga_aggregate_target=200M SCOPE=BOTH;

Official Reference: Oracle PGA Memory Management


Question 82: How can you use Oracle Database Segment Advisor for performance optimization?

Answer: Segment Advisor analyzes the segments of a database and makes recommendations for space reclamation and performance improvement.

Code Snippet (Running Segment Advisor):

-- Run Segment Advisor
EXEC DBMS_SPACE.ADVISE_SPACE_USAGE();

Official Reference: Oracle Segment Advisor


Question 83: What is the purpose of Oracle Database Automatic Diagnostic Repository (ADR) in performance tuning?

Answer: ADR collects diagnostic information that is useful for investigating and resolving database problems.

Official Reference: Oracle ADR


Question 84: How can you use Oracle Database Locking Mechanisms for performance optimization?

Answer: Oracle offers various locking mechanisms like row-level locks, table-level locks, and more to control access to data.

Code Snippet (Using Locks):

-- Apply Row-Level Lock
LOCK TABLE my_table IN ROW SHARE MODE;

Official Reference: Oracle Locking


Question 85: What is the purpose of Oracle Database Histograms in performance tuning?

Answer: Histograms provide improved optimizer statistics for better query performance.

Code Snippet (Creating a Histogram):

-- Create Histogram
BEGIN
  DBMS_STATS.GATHER_TABLE_STATS(
    ownname => 'schema_name',
    tabname => 'table_name',
    method_opt => 'FOR ALL COLUMNS SIZE 254'
  );
END;
/

Official Reference: Oracle Histograms


Question 86: How can you use Oracle Database Materialized Views for performance optimization?

Answer: Materialized Views store the results of a query, providing faster access to aggregated or precomputed data.

Code Snippet (Creating a Materialized View):

-- Create Materialized View
CREATE MATERIALIZED VIEW mv_name
BUILD IMMEDIATE REFRESH COMPLETE ON DEMAND AS
SELECT * FROM my_table;

Official Reference: Oracle Materialized Views


Question 87: What is the purpose of Oracle Database Flashback Technology in performance tuning?

Answer: Flashback Technology allows you to view and recover previous states of the database.

Official Reference: Oracle Flashback Technology


Question 88: How can you use Oracle Database Full-Table Caching for performance optimization?

Answer: Full-Table Caching loads the entire table into the cache, reducing disk I/O for frequent access.

Code Snippet (Enabling Full-Table Caching):

-- Enable Full-Table Caching
ALTER TABLE my_table CACHE;

Official Reference: Oracle Full-Table Caching


Question 89: What is the purpose of Oracle Database Partitioning in performance tuning?

Answer: Partitioning divides large tables into smaller, more manageable pieces for improved performance and manageability.

Official Reference: Oracle Partitioning


Question 90: How can you use Oracle Database Automatic Maintenance Tasks for performance optimization?

Answer: Automatic Maintenance Tasks automate routine database maintenance operations.

Official Reference: Oracle Automatic Maintenance Tasks


Question 91: What is Oracle Database In-Memory and how can it be used for performance optimization?

Answer: Oracle Database In-Memory allows for in-memory processing of data, significantly improving query performance.

Code Snippet (Enabling In-Memory Option):

-- Enable In-Memory Option
ALTER TABLE my_table INMEMORY;

Official Reference: Oracle Database In-Memory


Question 92: How can you use Oracle Database SQL Tuning Advisor for performance optimization?

Answer: SQL Tuning Advisor provides recommendations for improving the performance of SQL statements.

Code Snippet (Running SQL Tuning Advisor):

-- Run SQL Tuning Advisor
DECLARE
  my_task_name VARCHAR2(30);
BEGIN
  my_task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(
    sql_id => 'sql_id_here',
    scope => DBMS_SQLTUNE.SCOPE_COMPREHENSIVE,
    time_limit => 60,
    task_name => 'my_tuning_task',
    description => 'My Tuning Task'
  );
END;
/

Official Reference: Oracle SQL Tuning Advisor


Question 93: What is Oracle Database Real Application Testing (RAT) and how can it be used for performance tuning?

Answer: RAT enables testing and assessing the impact of system changes on a production-like database.

Official Reference: Oracle Real Application Testing


Question 94: How can you use Oracle Database Automatic SQL Plan Management for performance optimization?

Answer: SQL Plan Management automatically evolves and manages execution plans for improved performance.

Code Snippet (Creating SQL Plan Baseline):

-- Create SQL Plan Baseline
BEGIN
  DBMS_SPM.LOAD_PLANS_FROM_CURSOR_CACHE(
    sql_id => 'sql_id_here',
    plan_hash_value => null,
    fixed => 'NO',
    enabled => 'YES');
END;
/

Official Reference: Oracle SQL Plan Management


Question 95: What is the purpose of Oracle Database Automatic Workload Repository (AWR) in performance tuning?

Answer: AWR collects database statistics and workload information for performance analysis.

Official Reference: Oracle AWR


Question 96: How can you use Oracle Database Result Cache for performance optimization?

Answer: Result Cache stores the results of a query for reuse, reducing the overhead of expensive calculations.

Code Snippet (Enabling Result Cache):

-- Enable Result Cache for a Query
SELECT /*+ RESULT_CACHE */ column1, column2 FROM my_table;

Official Reference: Oracle Result Cache


Question 97: What is the purpose of Oracle Database Database Resource Manager in performance tuning?

Answer: Resource Manager allocates resources to different users and applications to ensure performance goals are met.

Official Reference: Oracle Resource Manager


Question 98: How can you use Oracle Database SQL Access Advisor for performance optimization?

Answer: SQL Access Advisor recommends indexes, materialized views, and other structures to improve query performance.

Code Snippet (Running SQL Access Advisor):

-- Run SQL Access Advisor
DECLARE
  my_task_name VARCHAR2(30);
BEGIN
  my_task_name := DBMS_ADVISOR.CREATE_TASK(
    advisor_name => 'Access_Advisor',
    task_name => 'My_Access_Task',
    task_desc => 'My Access Advisor Task'
  );
END;
/

Official Reference: Oracle SQL Access Advisor


Question 99: What is Oracle Database SQL Performance Analyzer (SPA) and how can it be used for performance tuning?

Answer: SPA helps assess the impact of system changes on SQL performance.

Official Reference: Oracle SQL Performance Analyzer


Question 100: How can you use Oracle Database Optimizer Statistics for performance optimization?

Answer: Optimizer Statistics provide vital information about database objects, aiding in query optimization.

Code Snippet (Gathering Statistics):

`sql -- Gather Optimizer Statistics BEGIN DBMS_STATS.GATHER_SCHEMA_STATS( ownname => 'schema_name', estimate_percent => DBMS_STATS.AUTO_SAMPLE_SIZE, method_opt => 'FOR ALL COLUMNS SIZE AUTO', degree => DBMS_STATS.DEFAULT_DEGREE, cascade => TRUE ); END; /`

Official Reference: Oracle Optimizer Statistics