The document provides an overview of Oracle Database locking mechanisms. It discusses key concepts such as reader-writer locks, row-level and table-level locks during DML operations, and how Oracle manages locks to maximize concurrency. It also covers advanced topics like deadlocks, blocked inserts, and unindexed foreign keys. The document demonstrates various locking scenarios and techniques for monitoring locks using Oracle dictionary views and tools.
The document discusses Oracle database locking mechanisms. It provides an overview of locks and how they ensure consistency and integrity. It describes Oracle's default locking behavior including reader/writer locks and how writers don't block readers. It also covers manual locking, deadlocks, blocking issues, and monitoring locks using dictionary views and tools.
The document provides an overview of Oracle Database locking mechanisms. It discusses the different types of locks used in Oracle including row-level locks, table-level locks, and different lock modes. It describes how Oracle uses row-level locking to allow non-blocking queries and read consistency. The document also covers advanced locking scenarios like deadlocks and blocked inserts. It concludes with demonstrating how to monitor locks using Oracle dictionary views and tools to identify blocked sessions.
Oracle Database 12c - The Best Oracle Database 12c Tuning Features for Develo...Alex Zaballa
Oracle Database 12c includes many new tuning features for developers and DBAs. Some key features include:
- Multitenant architecture allows multiple pluggable databases to consolidate workloads on a single database instance for improved utilization and administration.
- In-memory column store enables real-time analytics on frequently accessed data held entirely in memory for faster performance.
- New SQL syntax like FETCH FIRST for row limiting and offsetting provides more readable and intuitive replacements for previous techniques.
- Adaptive query optimization allows queries to utilize different execution plans like switching between nested loops and hash joins based on runtime statistics for improved performance.
GLOC 2014 NEOOUG - Oracle Database 12c New FeaturesBiju Thomas
This document discusses several new features in Oracle Database 12c for 11g DBAs. It covers improvements to administration and manageability such as online data file move, temporary undo, listener registration, and limiting PGA. New enhancements to tools and utilities are also presented, like Database Express 12c, enhanced patching, Data Pump NOLOGGING import, and improved features in RMAN. The document provides an overview of many updated features and directs readers to Oracle documentation for more details.
Oracle Database 12c - New Features for Developers and DBAsAlex Zaballa
This document summarizes a presentation about new features in Oracle Database 12c for developers and DBAs. It introduces JSON support, data redaction, SQL query row limits and offsets, invisible columns, extended data types, session level sequences, and more. Demo sections are included to illustrate several of the new features.
The document discusses Oracle database locking mechanisms. It provides an overview of locks and how they ensure consistency and integrity. It describes Oracle's default locking behavior including reader/writer locks and how writers don't block readers. It also covers manual locking, deadlocks, blocking issues, and monitoring locks using dictionary views and tools.
The document provides an overview of Oracle Database locking mechanisms. It discusses the different types of locks used in Oracle including row-level locks, table-level locks, and different lock modes. It describes how Oracle uses row-level locking to allow non-blocking queries and read consistency. The document also covers advanced locking scenarios like deadlocks and blocked inserts. It concludes with demonstrating how to monitor locks using Oracle dictionary views and tools to identify blocked sessions.
Oracle Database 12c - The Best Oracle Database 12c Tuning Features for Develo...Alex Zaballa
Oracle Database 12c includes many new tuning features for developers and DBAs. Some key features include:
- Multitenant architecture allows multiple pluggable databases to consolidate workloads on a single database instance for improved utilization and administration.
- In-memory column store enables real-time analytics on frequently accessed data held entirely in memory for faster performance.
- New SQL syntax like FETCH FIRST for row limiting and offsetting provides more readable and intuitive replacements for previous techniques.
- Adaptive query optimization allows queries to utilize different execution plans like switching between nested loops and hash joins based on runtime statistics for improved performance.
GLOC 2014 NEOOUG - Oracle Database 12c New FeaturesBiju Thomas
This document discusses several new features in Oracle Database 12c for 11g DBAs. It covers improvements to administration and manageability such as online data file move, temporary undo, listener registration, and limiting PGA. New enhancements to tools and utilities are also presented, like Database Express 12c, enhanced patching, Data Pump NOLOGGING import, and improved features in RMAN. The document provides an overview of many updated features and directs readers to Oracle documentation for more details.
Oracle Database 12c - New Features for Developers and DBAsAlex Zaballa
This document summarizes a presentation about new features in Oracle Database 12c for developers and DBAs. It introduces JSON support, data redaction, SQL query row limits and offsets, invisible columns, extended data types, session level sequences, and more. Demo sections are included to illustrate several of the new features.
Oracle Database 11g Release 2 includes enhancements to database administration features such as automated segment creation, audit trail management tools, and SQL*Plus exit behavior configuration; it also changes the installation process by making ASM a separate Grid Infrastructure and including full software updates in patch set installations.
Flashback operations allow recovering data from earlier points in time using undo and redo information. The Flash Recovery Area (FRA) stores files needed for flashback and recovery operations. Configuring the FRA involves specifying its size and location using parameters like DB_RECOVERY_FILE_DEST_SIZE and DB_RECOVERY_FILE_DEST. Flashback features like Flashback Query, Flashback Versions Query, and Flashback Database use information in the FRA to access earlier states of data.
This presentation explains all of the new features that are relevant for developers in Oracle 12c. It's been out for a couple of years, but many companies haven't updated to 12c. So, if you're looking to update soon, or are just interested in what the new features are, look at this presentation.
The full post is available at http://www.completeitprofessional.com/oracle-12c-new-features-for-developers
Oracle Database 12c includes many new features across SQL, PL/SQL, database management, partitioning, patching, compression, Data Guard, and pluggable databases. Key features include increased datatype size limits, identity columns, implicit result sets in PL/SQL, adaptive plans, row pattern matching, pluggable databases that can be plugged into and unplugged from container databases, and many enhancements to compression, partitioning, Data Guard, and patching functionality.
Oracle11g introduces several new security, configuration, and administration features for databases. Security features include case sensitive passwords by default and additional auditing of actions. Configuration is simplified with new memory management parameters and automatic diagnostic repository. Administration enhancements provide options to make tables read-only, shrink temporary tablespaces, and add not null columns without updating existing rows.
Watch the full webinar at: http://embt.co/1pb4Zb4
This presentation is a must-see for anyone interested in Oracle 12! Dan is an Oracle ACE Director and has assembled this presentation with fresh and inside information from Oracle Corp and OOW13. Dan has pulled his top Oracle 12 features from the plethora of new features available and documented in his user group presentations "Oracle 12c New Features for Developers" and "Oracle 12c New Features for DBA's".
Top 10 features will include:
New SQL Syntax
New SQL and PL/SQL Limits
Pluggable Database
New Packages
Deprecated Features
New SQL Tuning Features
This presentation covers new SQL & PL/SQL syntax and options, the container DB of course, new SQL optimizer features, deprecated features, hints, and more. If you're supporting applications, then you won't want to miss this webinar!
DBA Commands and Concepts That Every Developer Should KnowAlex Zaballa
DBA Commands and Concepts That Every Developer Should Know was presented by Alex Zaballa, an Oracle DBA with experience in Brazil and Angola. The presentation covered Oracle Flashback Query, Flashback Table, RMAN table recovery, pending statistics, explain plan, DBMS_APPLICATION_INFO, row-by-row vs bulk processing, Virtual Private Database, extended data types, SQL text expansion, identity columns, UTL_CALL_STACK, READ privileges vs SELECT privileges, and online table redefinition. The presentation included demonstrations of many of these concepts.
The document provides an overview of analyzing performance data using the Automatic Workload Repository (AWR) in Oracle databases. It discusses how AWR collects snapshots of data from V$ views over time and stores them in database history views. It highlights some key views used in AWR analysis and factors to consider like snapshot intervals and timestamps. Examples are provided to show how to query AWR views to identify top SQL statements by CPU usage and analyze performance metrics trends over time.
The biggest headine at the 2009 Oracle OpenWorld was when Larry Ellison announced that Oracle was entering the hardware business with a pre-built database machine, engineered by Oracle. Since then businesses around the world have started to use these engineered systems. This beginner/intermediate-level session will take you through my first 100 days of starting to administer an Exadata machine and all the roadblocks and all the success I had along this new path.
Oracle Database 12.1.0.2 introduced several new features including approximate count distinct, full database caching, pluggable database (PDB) improvements like cloning and state management, JSON support, data redaction, SQL query row limits and offsets, invisible columns, SQL text expansion, calling PL/SQL from SQL, session level sequences, and extended data types support.
The document discusses the top 12 new features of Oracle 12c, including improved column defaults that allow identity columns, increased size limits for VARCHAR columns up to 32K, improved queries for top-N results using ROW LIMIT clauses, and adaptive execution plans that allow the optimizer to choose alternative execution plans based on statistics gathered during the first execution. Temporary undo segments are also introduced to avoid generating redo for temporary table operations.
AWR DB performance Data Mining - Collaborate 2015Yury Velikanov
Oracle database AWR performance repository is a hidden treasure. There are a lot of very useful details about your systems behavior hidden in that repository. This presentation designed to give you all knowledge you need to start leveraging the data more than standard AWR based reports allows you. The author will walk you through several practical examples from his experience where AWR proven to be one of the best information sources. You will learn how to start accessing AWR tables and few areas you should be careful with. We will wrap up the presentation with more examples and Q&A section.
Objective 1: Give enough information to start mining AWR tables to extract performance data for troubleshooting different issues
Objective 2: Demonstrate practical examples on how AWR has been used to troubleshoot different performance problems
Objective 3: Let you consider AWR as a good additional source for performance issues troubleshooting
OOW16 - Oracle Database 12c - The Best Oracle Database 12c New Features for D...Alex Zaballa
This document provides an overview of new features in Oracle Database 12c for developers and DBAs. It begins with an introduction by Alex Zaballa and then covers several new features including native support for JSON, data redaction, row limits and offsets for SQL queries, PL/SQL functions callable from SQL, session level sequences, and temporary undo. The document includes demonstrations of many of these new features.
Understanding Query Optimization with ‘regular’ and ‘Exadata’ OracleGuatemala User Group
The document discusses query optimization with regular Oracle databases and Exadata databases. It explains what happens when a SQL statement is issued, including parsing, optimization, and execution. It describes what an execution plan is and how it can be generated and displayed. It discusses how operations can be offloaded to storage cells on Exadata and factors the optimizer considers for determining a good execution plan.
DBA Brasil 1.0 - DBA Commands and Concepts That Every Developer Should KnowAlex Zaballa
This document summarizes a presentation on DBA commands and concepts that every developer should know. The presentation covers topics such as:
- Using SQLcl and tools like dbms_xplan to analyze queries and explain plans
- Leveraging parallelism to improve query performance
- Using flashback queries to view past data states
- Recovering dropped or corrupted tables using flashback and recycle bin features
- Migrating and restoring statistics to support testing and troubleshooting
The presentation provides examples and demonstrations of commands for tasks like analyzing queries, improving performance, recovering data, and managing database metadata.
This document provides an introduction and overview of Oracle Linux and its suitability for running Oracle databases. It discusses the Unbreakable Enterprise Kernel, installation of Oracle Linux, directory structure considerations, useful Linux commands for Oracle DBAs, file system options like OCFS2 and BTRFS, and demonstrates cloning a database using OCFS2 snapshot capabilities. The presenter has extensive experience with Oracle databases and various Oracle Linux versions.
Oracle uses different lock modes to maintain data concurrency and integrity. Row-level locks are acquired during DML statements to prevent other sessions from modifying the same rows. Table locks are also acquired to prevent DDL operations from conflicting with transactions. Deadlocks can occur when two sessions block each other by locking resources the other needs. Oracle automatically detects and resolves deadlocks by rolling back one of the sessions.
Oracle Database 12c - New Features for Developers and DBAsAlex Zaballa
Oracle Database 12c includes over 500 new features designed to support cloud computing, big data, security, and availability. Key features include support for up to 4096 pluggable databases, hot cloning without placing the source database in read-only mode, sharding capabilities, in-memory column storage, application containers, improved resource management isolation, and AWR support on Active Data Guard databases. Other notable features include enhanced JSON support, data redaction for security, row limits and offsets for queries, invisible columns, SQL text expansion, PL/SQL from SQL, session-level sequences, extended data types up to 32K, multiple indexes on the same columns, READ privileges without row locking ability, session private statistics for global temporary tables,
Oracle Database 11g Release 2 includes enhancements to database administration features such as automated segment creation, audit trail management tools, and SQL*Plus exit behavior configuration; it also changes the installation process by making ASM a separate Grid Infrastructure and including full software updates in patch set installations.
Flashback operations allow recovering data from earlier points in time using undo and redo information. The Flash Recovery Area (FRA) stores files needed for flashback and recovery operations. Configuring the FRA involves specifying its size and location using parameters like DB_RECOVERY_FILE_DEST_SIZE and DB_RECOVERY_FILE_DEST. Flashback features like Flashback Query, Flashback Versions Query, and Flashback Database use information in the FRA to access earlier states of data.
This presentation explains all of the new features that are relevant for developers in Oracle 12c. It's been out for a couple of years, but many companies haven't updated to 12c. So, if you're looking to update soon, or are just interested in what the new features are, look at this presentation.
The full post is available at http://www.completeitprofessional.com/oracle-12c-new-features-for-developers
Oracle Database 12c includes many new features across SQL, PL/SQL, database management, partitioning, patching, compression, Data Guard, and pluggable databases. Key features include increased datatype size limits, identity columns, implicit result sets in PL/SQL, adaptive plans, row pattern matching, pluggable databases that can be plugged into and unplugged from container databases, and many enhancements to compression, partitioning, Data Guard, and patching functionality.
Oracle11g introduces several new security, configuration, and administration features for databases. Security features include case sensitive passwords by default and additional auditing of actions. Configuration is simplified with new memory management parameters and automatic diagnostic repository. Administration enhancements provide options to make tables read-only, shrink temporary tablespaces, and add not null columns without updating existing rows.
Watch the full webinar at: http://embt.co/1pb4Zb4
This presentation is a must-see for anyone interested in Oracle 12! Dan is an Oracle ACE Director and has assembled this presentation with fresh and inside information from Oracle Corp and OOW13. Dan has pulled his top Oracle 12 features from the plethora of new features available and documented in his user group presentations "Oracle 12c New Features for Developers" and "Oracle 12c New Features for DBA's".
Top 10 features will include:
New SQL Syntax
New SQL and PL/SQL Limits
Pluggable Database
New Packages
Deprecated Features
New SQL Tuning Features
This presentation covers new SQL & PL/SQL syntax and options, the container DB of course, new SQL optimizer features, deprecated features, hints, and more. If you're supporting applications, then you won't want to miss this webinar!
DBA Commands and Concepts That Every Developer Should KnowAlex Zaballa
DBA Commands and Concepts That Every Developer Should Know was presented by Alex Zaballa, an Oracle DBA with experience in Brazil and Angola. The presentation covered Oracle Flashback Query, Flashback Table, RMAN table recovery, pending statistics, explain plan, DBMS_APPLICATION_INFO, row-by-row vs bulk processing, Virtual Private Database, extended data types, SQL text expansion, identity columns, UTL_CALL_STACK, READ privileges vs SELECT privileges, and online table redefinition. The presentation included demonstrations of many of these concepts.
The document provides an overview of analyzing performance data using the Automatic Workload Repository (AWR) in Oracle databases. It discusses how AWR collects snapshots of data from V$ views over time and stores them in database history views. It highlights some key views used in AWR analysis and factors to consider like snapshot intervals and timestamps. Examples are provided to show how to query AWR views to identify top SQL statements by CPU usage and analyze performance metrics trends over time.
The biggest headine at the 2009 Oracle OpenWorld was when Larry Ellison announced that Oracle was entering the hardware business with a pre-built database machine, engineered by Oracle. Since then businesses around the world have started to use these engineered systems. This beginner/intermediate-level session will take you through my first 100 days of starting to administer an Exadata machine and all the roadblocks and all the success I had along this new path.
Oracle Database 12.1.0.2 introduced several new features including approximate count distinct, full database caching, pluggable database (PDB) improvements like cloning and state management, JSON support, data redaction, SQL query row limits and offsets, invisible columns, SQL text expansion, calling PL/SQL from SQL, session level sequences, and extended data types support.
The document discusses the top 12 new features of Oracle 12c, including improved column defaults that allow identity columns, increased size limits for VARCHAR columns up to 32K, improved queries for top-N results using ROW LIMIT clauses, and adaptive execution plans that allow the optimizer to choose alternative execution plans based on statistics gathered during the first execution. Temporary undo segments are also introduced to avoid generating redo for temporary table operations.
AWR DB performance Data Mining - Collaborate 2015Yury Velikanov
Oracle database AWR performance repository is a hidden treasure. There are a lot of very useful details about your systems behavior hidden in that repository. This presentation designed to give you all knowledge you need to start leveraging the data more than standard AWR based reports allows you. The author will walk you through several practical examples from his experience where AWR proven to be one of the best information sources. You will learn how to start accessing AWR tables and few areas you should be careful with. We will wrap up the presentation with more examples and Q&A section.
Objective 1: Give enough information to start mining AWR tables to extract performance data for troubleshooting different issues
Objective 2: Demonstrate practical examples on how AWR has been used to troubleshoot different performance problems
Objective 3: Let you consider AWR as a good additional source for performance issues troubleshooting
OOW16 - Oracle Database 12c - The Best Oracle Database 12c New Features for D...Alex Zaballa
This document provides an overview of new features in Oracle Database 12c for developers and DBAs. It begins with an introduction by Alex Zaballa and then covers several new features including native support for JSON, data redaction, row limits and offsets for SQL queries, PL/SQL functions callable from SQL, session level sequences, and temporary undo. The document includes demonstrations of many of these new features.
Understanding Query Optimization with ‘regular’ and ‘Exadata’ OracleGuatemala User Group
The document discusses query optimization with regular Oracle databases and Exadata databases. It explains what happens when a SQL statement is issued, including parsing, optimization, and execution. It describes what an execution plan is and how it can be generated and displayed. It discusses how operations can be offloaded to storage cells on Exadata and factors the optimizer considers for determining a good execution plan.
DBA Brasil 1.0 - DBA Commands and Concepts That Every Developer Should KnowAlex Zaballa
This document summarizes a presentation on DBA commands and concepts that every developer should know. The presentation covers topics such as:
- Using SQLcl and tools like dbms_xplan to analyze queries and explain plans
- Leveraging parallelism to improve query performance
- Using flashback queries to view past data states
- Recovering dropped or corrupted tables using flashback and recycle bin features
- Migrating and restoring statistics to support testing and troubleshooting
The presentation provides examples and demonstrations of commands for tasks like analyzing queries, improving performance, recovering data, and managing database metadata.
This document provides an introduction and overview of Oracle Linux and its suitability for running Oracle databases. It discusses the Unbreakable Enterprise Kernel, installation of Oracle Linux, directory structure considerations, useful Linux commands for Oracle DBAs, file system options like OCFS2 and BTRFS, and demonstrates cloning a database using OCFS2 snapshot capabilities. The presenter has extensive experience with Oracle databases and various Oracle Linux versions.
Oracle uses different lock modes to maintain data concurrency and integrity. Row-level locks are acquired during DML statements to prevent other sessions from modifying the same rows. Table locks are also acquired to prevent DDL operations from conflicting with transactions. Deadlocks can occur when two sessions block each other by locking resources the other needs. Oracle automatically detects and resolves deadlocks by rolling back one of the sessions.
Oracle Database 12c - New Features for Developers and DBAsAlex Zaballa
Oracle Database 12c includes over 500 new features designed to support cloud computing, big data, security, and availability. Key features include support for up to 4096 pluggable databases, hot cloning without placing the source database in read-only mode, sharding capabilities, in-memory column storage, application containers, improved resource management isolation, and AWR support on Active Data Guard databases. Other notable features include enhanced JSON support, data redaction for security, row limits and offsets for queries, invisible columns, SQL text expansion, PL/SQL from SQL, session-level sequences, extended data types up to 32K, multiple indexes on the same columns, READ privileges without row locking ability, session private statistics for global temporary tables,
This document discusses managing data and concurrency in Oracle databases. It covers using SQL to manipulate data, administering PL/SQL objects, triggers and triggering events, and monitoring and resolving locking conflicts. Key topics include the INSERT, UPDATE, DELETE commands; PL/SQL functions, procedures and packages; trigger events; locking mechanisms like row-level locks; detecting and resolving lock conflicts; and avoiding deadlocks. The goal is to teach database administrators how to work with these concepts.
Jonathan is a MySQL consultant who specializes in SQL, indexing, and reporting for big data. This tutorial will cover strategies for resolving 80% of performance problems, including indexes, partitioning, intensive table optimization, and finding and addressing bottlenecks. The strategies discussed will be common, established approaches based on the presenter's experience working with MySQL since 2007.
This document provides an overview of various Oracle database tuning tools available in Oracle 10gR2, including the Automatic Workload Repository (AWR), Automatic Database Diagnostic Monitor (ADDM), Active Session History (ASH), metrics, and advisors. It discusses how these tools provide automated, consistent performance monitoring and issue identification to help tune and optimize the database with little manual effort.
DBA Commands and Concepts That Every Developer Should Know - Part 2Alex Zaballa
This document provides a summary of several database administration (DBA) commands and concepts relevant for developers. It discusses topics such as count(1) vs count(*), gathering system statistics, setting the DB_FILE_MULTIBLOCK_READ_COUNT parameter, analyzing tables, explaining plans, monitoring SQL performance, full table scans, pending statistics, restoring statistics history, parallel DML, Flashback Query, DBMS_APPLICATION_INFO, and privileges for reading tables. The document is intended to help developers better understand and work with database configurations and operations.
DBA Commands and Concepts That Every Developer Should Know - Part 2Alex Zaballa
This document provides a summary of several database administration (DBA) commands and concepts relevant for developers. It discusses topics such as count(1) vs count(*), gathering system statistics, setting the DB_FILE_MULTIBLOCK_READ_COUNT parameter, analyzing tables, explaining plans, monitoring SQL performance, full table scans, pending statistics, restoring statistics history, parallel DML, Flashback Query, DBMS_APPLICATION_INFO, schema management, adding columns with defaults, object and system privileges. The document is intended to help developers better understand and work with database concepts.
Oracle SQL tuning involves optimizing SQL statements for better performance. Key aspects of SQL tuning include identifying SQL statements with high resource consumption or response times using tools like ADDM, AWR, and V$SQL. Statements can then be tuned by gathering accurate optimizer statistics, adjusting the execution plan using hints, rewriting the SQL, or changing indexes and tables. Tuning is done at both the design and execution stages.
This presentation provided techniques for securing an Oracle database, including: securing Oracle binaries and dump files; restricting and monitoring the listener; limiting privileges and authentication; implementing comprehensive auditing; and protecting data outside of production. The key areas discussed were securing the database binaries and directories, protecting the listener as a single point of failure, following the principle of least privilege, auditing for privilege escalation and changes to the audit trail, and securing backups and development data. The overall message was that firewalls alone are not enough and a layered security approach is needed to properly secure an Oracle database.
This document provides an overview and agenda for a presentation on Oracle Database Vault. It discusses securing data using realms, factors, command rules and rule sets in Database Vault. It also covers auditing violations which are logged in the database and to the operating system. The document concludes with a brief section on the impact of backups on a Database Vault secured system when using export, Data Pump and RMAN.
The document summarizes new features in Oracle Database 12c from Oracle 11g that would help a DBA currently using 11g. It lists and briefly describes features such as the READ privilege, temporary undo, online data file move, DDL logging, and many others. The objectives are to make the DBA aware of useful 12c features when working with a 12c database and to discuss each feature at a high level within 90 seconds.
Security Best Practice: Oracle passwords, but secure!Stefan Oehrli
This document summarizes a presentation on securing Oracle passwords. It discusses Oracle's password hashing algorithms over different versions from 10g to 12c. It describes Oracle's logon process and how passwords are encrypted and verified. It highlights some challenges with Oracle passwords like weaknesses in hash functions, compatibility issues, and risks in the login process. It emphasizes the importance of properly configuring password versions and hashes when upgrading or migrating databases.
This document provides a summary of new features and enhancements in MySQL 5.6, including improved performance, scalability, availability, and usability. Key highlights include optimizations to the query optimizer, enhanced instrumentation via the performance schema, improvements to InnoDB and replication, and new utilities to help administer replication deployments. Oracle aims to release development milestone versions of MySQL frequently to get new features in users' hands early.
Oracle 23c offers cutting edge database security features for audit, encryption, authentication, authorization. SQL firewall provides real-
time protection from attacks and mitigate risks from SQL injection attacks, anomalous access, credential abuse or theft with centralized
administration.
The document discusses new features and improvements in MySQL 5.6, including significant performance gains over MySQL 5.5. Key highlights include improved InnoDB performance through features like online DDL and buffer pool pre-loading, up to 151-234% performance gains on benchmarks. Other enhancements cover full-text search in InnoDB, NoSQL support through memcached integration, replication improvements with GTIDs and crash-safe slaves, and strengthened security with audit logging and password policies.
"Dear Students,
Greetings from www.etraining.guru
We provide BEST online training for IBM DB2 LUW/UDB DBA by a database architect. Our DB2 Trainer comes with a working experience of 11+ years, 9+ years in DB2 and a DB2 certified professional.
DB2 LUW DBA Course Content: http://www.etraining.guru/course/dba/online-training-db2-luw-udb-dba
Course Cost: USD 350 (or) INR 21000
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"Dear Students,
Greetings from www.etraining.guru
We provide BEST online training for IBM DB2 LUW/UDB DBA by a database architect. Our DB2 Trainer comes with a working experience of 11+ years, 9+ years in DB2 and a DB2 certified professional.
DB2 LUW DBA Course Content: http://www.etraining.guru/course/dba/online-training-db2-luw-udb-dba
Course Cost: USD 350 (or) INR 21000
Number of Hours: 30-35 hours
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IBM DB2 LUW UDB DBA Online Training by Etraining Guru In HyderabadRavikumar Nandigam
This 32-hour course covers administration of DB2 on Linux and provides an in-depth look at database configuration, maintenance, performance tuning, and high availability. The course is divided into 14 units covering topics such as database creation, backup and recovery, security, locking, monitoring, and setting up high availability configurations. Hands-on exercises are included to reinforce key concepts for tasks like database installation, loading data, and using diagnostic tools.
"Dear Students,
Greetings from www.etraining.guru
We provide BEST online training for IBM DB2 LUW/UDB DBA by a database architect. Our DB2 Trainer comes with a working experience of 11+ years, 9+ years in DB2 and a DB2 certified professional.
DB2 LUW DBA Course Content: http://www.etraining.guru/course/dba/online-training-db2-luw-udb-dba
Course Cost: USD 350 (or) INR 21000
Number of Hours: 30-35 hours
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This document discusses using SQL in FileMaker. It provides an overview of executing SQL statements using ExecuteSQL() and a plug-in called DoSQL 2. It covers the main SQL commands supported like SELECT, INSERT, UPDATE, DELETE. It also discusses topics like parameters, results, errors, logging and debugging. Common mistakes when using SQL are also outlined.
Similar to Pini Dibask - Oracle Database Locking Mechanism Demystified (Presentation) (20)
The document discusses Oracle Data Guard, a disaster recovery solution for Oracle databases. It provides:
1) An overview of Data Guard, explaining that it maintains a physical or logical standby copy of the primary database to enable failover in the event of outages or disasters.
2) Details on the different types of standby databases - physical, logical, and snapshot - and how they are maintained through redo application or SQL application.
3) The various Data Guard configuration options like real-time apply, time delay, and role transitions such as switchover and failover.
Winning performance challenges in oracle standard editionsPini Dibask
This document provides a summary of a presentation about winning performance challenges in Oracle Standard Editions. The presentation discusses:
1. The performance tuning challenges that exist in Oracle Standard Editions due to the lack of diagnostics packs.
2. Approaches for performance monitoring and diagnostics using Statspack and Oracle dictionary views in Standard Editions.
3. How Foglight for Databases can provide visibility into database performance and workloads across all Oracle editions and configurations.
Winning performance challenges in oracle multitenantPini Dibask
This document provides an overview of winning performance challenges in Oracle Multitenant environments. It discusses Oracle Multitenant concepts, ensuring quality of service in multitenant databases, using RAC with multitenant, and performance monitoring for multitenant databases. The speaker is Pini Dibask, Product Manager for Database Monitoring at Quest Software.
Winning performance challenges in oracle standard editionsPini Dibask
This document discusses winning performance challenges in Oracle Standard Editions, which lack advanced diagnostics features only available in the Enterprise Edition. It recommends using Statspack and dictionary views to monitor performance. Foglight for Databases is presented as an alternative that provides visualization and cross-platform monitoring without spending on the Enterprise Edition. Specific techniques demonstrated include execution plan analysis, blocking lock detection, workload baselining and multi-dimensional analysis of waits and statistics.
This document provides an overview and introduction to Oracle Data Guard for beginners. It discusses:
- The different types of standby databases including physical, logical, and snapshot standbys.
- The various modes and options for configuring Data Guard such as real-time apply, time delay, and data protection modes.
- Role transitions including planned switchovers and unplanned failovers.
- How the Data Guard broker can be used to centrally manage Data Guard configurations.
- Some limitations of when Data Guard may not be the best solution.
- Tools for monitoring Data Guard configurations such as database views and monitoring solutions from Quest Software.
IOUG Collaborate 18 - Data Guard for BeginnersPini Dibask
The document discusses Oracle Data Guard, including:
- It provides a high-level overview of Oracle Data Guard and its basic concepts of high availability and disaster recovery.
- It describes the different types of standby databases (physical, logical, snapshot), modes (maximum protection, availability, performance), and options in Data Guard.
- It explains key Data Guard components and architecture like redo transport, apply services, role transitions, and the Data Guard broker.
IOUG Collaborate 18 - ASM Concepts, Architecture and Best PracticesPini Dibask
Pini Dibask presented on Oracle ASM concepts, architecture, and best practices. Some key points:
- ASM is Oracle's recommended storage management solution and provides high performance storage for single-instance and RAC databases.
- ASM uses disk groups and stripes and mirrors data across disks for redundancy and load balancing. It also rebalances data automatically during storage changes.
- Administering ASM involves tasks like starting and stopping the ASM instance, managing disk groups and disks, and monitoring storage usage and I/O balance.
- Best practices for ASM include using separate disk groups for data and recovery files, ensuring consistent disk performance, monitoring I/O balance, and in
RMOUG 18 - Winning Performance Challenges in Oracle MultitenantPini Dibask
This document discusses winning performance challenges in Oracle Multitenant environments. It begins with introducing the speaker, Pini Dibask, who is a Product Manager for Database Tools at Quest Software. It then provides an overview of Quest Software and their database management solutions. The remainder of the document outlines the agenda, which includes introductions to database consolidation, Oracle Multitenant concepts, ensuring quality of service in multitenant environments, RAC and multitenancy, and performance monitoring for multitenant environments.
Winning Performance Challenges in Oracle MultitenantPini Dibask
Pini Dibask, a senior product manager at Quest Software, gave a presentation on winning performance challenges in Oracle Multitenant. The presentation covered Oracle Multitenant concepts, ensuring quality of service in multitenant environments through resource management, using RAC with multitenant, and performance monitoring tools. It discussed how Oracle Resource Manager can be used to allocate resources between pluggable databases at the container database level. The presentation also showed how tools from Quest such as Foglight can provide performance monitoring across multiple databases.
OOW 17 - database consolidation using the oracle multitenant architecturePini Dibask
This document discusses database consolidation using Oracle Multitenant. It begins with an introduction to multitenant architecture and concepts. It then covers ensuring quality of service in multitenant environments using Oracle Resource Manager. The document also discusses using RAC with multitenant databases and performance monitoring for multitenant environments.
OUGN winning performnace challenges in oracle MultitenantPini Dibask
This document provides an overview and introduction to Oracle 12c Multitenant architecture. It discusses key features such as pluggable databases (PDBs), container databases (CDBs), and the benefits of consolidation. The document also covers best practices for ensuring quality of service (QoS) between PDBs using resource management. It describes using the Oracle resource manager to allocate resources at the CDB and PDB level. Lastly, it summarizes performance monitoring in multitenant environments with Automatic Workload Repository (AWR) functionality in 12c Release 1 and 2.
Collaborate 17 - Database consolidation using the oracle multitenant architec...Pini Dibask
The document provides an overview of database consolidation using Oracle Multitenant architecture. It discusses challenges with prior consolidation approaches and how Multitenant addresses these. Key concepts covered include pluggable databases, container databases, and resource management capabilities at the CDB and PDB level. The document also discusses how Multitenant supports high availability features like RAC and performance monitoring tools like AWR.
Database Consolidation using the Oracle Multitenant ArchitecturePini Dibask
The document discusses Oracle's Multitenant architecture, which allows multiple pluggable databases (PDBs) to consolidate within a single multitenant container database (CDB). It describes how Multitenant provides advantages like simplified upgrades, cloning, and migration of PDBs. The document also covers ensuring quality of service for PDBs using resource management, and how RAC supports high availability and scalability in a Multitenant environment. It concludes with a discussion of performance monitoring of workloads across PDBs.
2. Confidential2
• Pini Dibask, Product Manager, Database Solutions (Quest)
• Oracle DBA since 2006
• Oracle Certified Professional DBA (OCP)
• My Blog: OracleDBPro.BlogSpot.com
Pini.Dibask@Quest.com
http://Linkedin.com/in/pinidibask
@pini_dibask
About Me
3. Confidential3
About
• Quest is now an independent company again!
• Simplifies IT management
• #1 independent software company for Database Tools
• Driven by innovation
“Spend less time on what you need to do, and more time on what you want to do!”
• Committed to providing great products and superior support
4. Confidential4
• Overview of Locks in Database Management Systems
• Oracle Database Locking Mechanism Concepts
• Advanced Locking Scenarios
• Monitoring Locks using Dictionary Views and Tools
Agenda
6. Confidential6
• Why locks? Because Databases need to support multiple user applications
• Used to ensure Database Consistency and Integrity
• Affect the interaction of readers and writers
• Every DBMS has its own implementation of locking mechanism
Overview of Database Locks
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• Reader never blocks reader
• Reader never blocks writer
(except: SELECT .. FOR UPDATE)
• Writer never blocks reader
(except rare scenario of distributed transaction)
• Writer might block writer
(depends on the operation)
High Level Overview
Reader Writer
Reader No Block No Block
Writer No Block Block
9. Confidential9
• Oracle blocks can be modified during execution of DMLs
• Undo Tablespace holds “before” image of Database Blocks
• During SELECT query Oracle reads undo images if needed
• This provides 2 important features:
• Non-Blocking Queries
• Read Consistency
Writer Never Blocks Reader - How?
“Before” Image
placed in Undo
Tablespace
Session
updates a
record
Oracle
reconstructs
the block using
undo image
Undo
Tablespace
10. Confidential10
• 2 Lock Modes in general:
• Share Lock – Many can be acquired on a resource
• Exclusive Lock – Only one can be acquired on a resource
• Example - User updates a row in table EMPLOYEES
• Row will be locked in exclusive mode
• Table will be locked in share mode
Lock Modes
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• Oracle uses row-level locking during DML operations
• Modified rows will be locked in exclusive lock mode
• Oracle stores lock information in the containing data block header
• No overhead with Oracle row-level locking mechanism
DML Row Locks (“TX Locks”)
13. Confidential13
Session #2
SQL> UPDATE employees SET name = 'Mark' WHERE id = 1;
1 row updated.
Session #1
SQL> CREATE TABLE employees (id NUMBER, name VARCHAR2 (20));
Table created.
SQL> INSERT INTO employees VALUES (1, 'David');
1 row created.
SQL> INSERT INTO employees VALUES (2, 'Jason');
1 row created.
SQL> commit;
Commit complete.
DML Row Locks (“TX Locks”) - Demo
SQL> UPDATE employees SET name = 'Peter' WHERE id = 2;
1 row updated.
Row already
locked by
session #1
SQL> UPDATE employees SET name = 'John' WHERE id = 2;
(waiting – session is blocked)
14. Confidential14
• Oracle automatically locks tables (share mode) involved in DML operations
• Prevent DDL operations which may conflict with running transactions
Table Locks (“TM Locks”) Cont’d
EMPLOYEE_ID LAST_NAME EMAIL HIRE_DATE JOB_ID MANAGER_ID DEPARTMENT_ID
100 King SKING 17-JUN-87 AD_PRES 90
101 Kochhar NKOCHHAR 21-SEP-89 AD_VP 100 90
102 De Hann LDEHANN 13-JAN-93 AD_VP 100 90
103 Hunold AHUNOLD 03-JAN-90 IT_PROG 102 60
Table EMPLOYEES
Table lock acquired Exclusive row lock (TX) acquired Row being updated
16. Confidential16
DML Locks - Demo
SQL> UPDATE employee
2 SET last_name = 'Jones'
3 WHERE employee_id = 139;
1 row updated.
SQL> SELECT type, lmode
FROM v$lock
WHERE sid = 383;
TYPE LMODE
----- ----------
TX 6
TM 3
(Session ID #383)
Row of
employee_id #139
is locked in
LMODE 6 -
Exclusive (x)
Table EMPLOYEE
is locked in
LMODE 3 - Row
Exclusive Table
Lock (RX)
SQL> SELECT object_name,
session_id,
oracle_username,
locked_mode
FROM v$locked_object JOIN dba_objects USING (object_id);
OBJECT_NAME SESSION_ID ORACLE_USERNAME LOCKED_MODE
---------------- ------------- ----------------------- -----------------
EMPLOYEE 383 SALES 3
17. Confidential17
• Protect definition of schema objects during DDL statements
• Exclusive Locks (LMODE = 6)
• Most DDL Operations (e.g. ALTER TABLE, DROP TABLE)
• Other sessions cannot execute DML or DDL on the object
• Share Locks
• Allow data concurrency for similar operations
• Only modified objects are locked - Oracle never locks entire Data Dictionary
DDL Locks
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• Problem
• DDL commands (e.g. ALTER TABLE, DROP TABLE) require exclusive locks (LMODE = 6)
• It’s hard to acquire exclusive lock on frequently accessed object
• Solution
• DDL_LOCK_TIMEOUT parameter (available from Oracle 11g)
• Specifies time limit for how long DDL statements will wait in DML lock queue
• Default value is 0
• Can be set at session level (ALTER SESSION) or instance level (ALTER SYSTEM)
DDL Locks Cont’d
19. Confidential19
Session #1
SQL> UPDATE employee
SET last_name = 'Jones'
WHERE employee_id = 139;
1 row updated.
DDL Locks - Demo
SQL> alter system set ddl_lock_timeout=10;
System altered.
SQL> drop table employee;
drop table employee
*
ERROR at line 1:
ORA-00054: resource busy and acquire with NOWAIT
specified or timeout expired
Session #2
SQL> drop table employee;
drop table employee
*
ERROR at line 1:
ORA-00054: resource busy and acquire with NOWAIT
specified or timeout expired
Table already
locked in
share mode
Available
from version
11g
Oracle waits
10 seconds
before raising
this error
20. Confidential20
• Oracle automatically manages locks
• Locks will be released once transaction is over
• Lowest lock level will be used for maximum concurrency
• Oracle Database never escalates locks
• Ordering of locks is based on FIFO (First-In-First-Out)
How Oracle Manages Locks?
21. Confidential21
FIFO Lock Ordering - Demo
Session #1
SQL> SELECT * FROM employees;
EMP_ID NAME DEPT_ID
---------- ------------ ----------
1 David 3
2 John 4
SQL> UPDATE employees
SET name = 'Greg'
WHERE emp_id = 1;
1 row updated.
Session #2
SQL> LOCK TABLE employees
IN EXCLUSIVE MODE;
(waiting – session is blocked)
Session #3
SQL> UPDATE employees
SET name = 'Daniel'
WHERE emp_id = 2;
(waiting – session is blocked)
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• It is possible to override Oracle’s default locking mechanisms
• Should be avoided unless there is a justified application requirement
Example: Transaction needs exclusive access to resource and must not wait for other transactions
• Manual row-level locks: SELECT … FOR UPDATE statement
• Manual table-level locks: LOCK TABLE statement
Manual Data Locks
23. Confidential23
Manual Row Locks - Demo
Session #1
SQL> SELECT id, name
FROM employees
WHERE id = 2 FOR UPDATE;
ID NAME
------------------------------
2 Jason
Session #2
SQL> UPDATE employees SET name = 'Mark' WHERE id = 1;
1 row updated.
SQL> UPDATE employees SET name = 'John' WHERE id = 2;
(waiting – session is blocked)
24. Confidential24
Manual Table Locks - Demo
• LOCK TABLE IN [ ROW SHARE | ROW EXCLUSIVE | SHARE | SHARE ROW EXCLUSIVE | EXCLUSIVE ] MODE
Session #1 (SID 385)
SQL> SELECT * FROM employees FOR UPDATE;
ID NAME
------------------------------
2 Jason
Session #2 (SID 195)
SQL> LOCK TABLE employees IN ROW SHARE MODE;
Table(s) Locked.
SQL> LOCK TABLE employees IN EXCLUSIVE MODE;
(waiting - session is blocked)
SQL> SELECT sid, lmode acquired, request, blocking_session, SQL_TEXT
FROM v$lock l JOIN v$session s USING (sid) LEFT JOIN v$sqlarea USING (sql_id)
WHERE block = 1 OR request > 0 ;
SID ACQUIRED REQUEST BLOCKING_SESSION SQL_TEXT
---------- --------------- ---------- ---------------------- ------------------------------------------------
385 3 0
195 2 6 385 LOCK TABLE employees in exclusive mode
26. Confidential26
• 2 sessions, each one locking resource that other session wants
• At this stage both could become blocked forever
• Oracle automatically detects deadlock scenarios
• One of 2 sessions will be “Deadlock Victim”
• Oracle performs statement-level rollback
Deadlocks
Session 1 Session 2
Resource 1 Resource 2
Is holdingIs holding Wants
27. Confidential27
SQL> UPDATE employee
SET first_name = 'Mark'
WHERE employee_id = 39;
(Waiting - session is blocked)
Deadlocks - Demo
Session #1
SQL> UPDATE employee
SET first_name = 'David'
WHERE employee_id = 151;
1 row updated.
SQL> UPDATE employee
SET first_name = 'John'
WHERE employee_id = 151;
(Waiting - session is blocked)
Session #2
SQL> UPDATE employee
SET first_name = 'Greg'
WHERE employee_id = 39;
1 row updated.
Row already
locked by
session #2
ORA-00060: deadlock detected while waiting for resource
Row already
locked by
session #1
Statement
has been
rolled-back
30. Confidential30
• Most common scenario of blocked inserts:
• 2 sessions insert same value for column that has unique or primary key
• Another scenario that involves tables with foreign keys
• Row inserted/deleted on the parent table
• Row inserted to the child table - may be blocked
Blocked Inserts
31. Confidential31
Session #2
SQL> insert into employees values (1, 'David');
(waiting – row already locked by session #1)
Blocked Inserts - Demo
Session #1
SQL> CREATE TABLE employees
(
id NUMBER,
name VARCHAR2 (20),
CONSTRAINT pk_id PRIMARY KEY (id)
);
Table created.
SQL> insert into employees values (1, 'John');
1 row created.
*
ERROR at line 1:
ORA-00001:
unique constraint (SALES.PK_ID) violated
SQL> commit;
Commit complete.
37. Confidential37
• V$SESSION - Lists session information for each current session
• V$LOCK/DBA_LOCK - Lists all locks currently held and all requests for a lock
• V$LOCKED_OBJECT - Lists sessions holding locks on what objects and in what mode
• DBA_BLOCKERS - Lists sessions holding a lock that blocks another session
• DBA_WAITERS - Lists sessions that are waiting for a lock
Monitoring locks via Oracle Dictionary Views
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Monitoring locks via Oracle Dictionary Views Cont’d
SQL> SELECT DECODE (blocking_session, null, null, 'BLOCKED') status,
sid,
lmode,
request,
ctime duration,
USER,
program,
blocking_session,
DECODE (request, 0, NULL, SQL_TEXT) SQL_TEXT
FROM v$lock l
JOIN v$session s USING (sid)
LEFT JOIN v$sqlarea USING (sql_id)
WHERE block = 1 OR request > 0
ORDER BY status
STATUS SID LMODE REQUEST DURATION USER PROGRAM BLOCKING_SESSION SQL_TEXT
----------- ---------- ---------- ---------- ---------- ------- ----------- ---------------------------- ------------------------------------------------
BLOCKED 195 4 5 16581 SALES sqlplus.exe 385 lock table employees in share row exclusive mode
BLOCKED 13 0 3 10129 SALES Toad.exe 385 insert into employees values (1, 'Jason')
385 4 0 16575 SALES sqlplus.exe
Real-Time
Monitoring
45. Confidential45
• Is lock a bad thing? No! Locks are essential!
• Hold locks as long as you need, but not more than you need
• Avoid Manual Locking unless it is justified
• Foreign keys in most cases should be indexed
• Proactively monitor your Database to identify blocked sessions
• Modify application code if needed
Summary