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SQL Server deadlock example
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2015/08/sql-server-deadlock-example.html Slides http://csharp-video-tutorials.blogspot.com/2015/08/sql-server-deadlock-example_25.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists When can a deadlock occur In a database, a deadlock occurs when two or more processes have a resource locked, and each process requests a lock on the resource that another process has already locked. Neither of the transactions here can move forward, as each one is waiting for the other to release the lock. When deadlocks occur, SQL Server will choose one of processes as the deadlock victim and rollback that process, so the other process can move forward. The transaction that is chosen as the deadlock victim will produce the following error. Msg 1205, Level 13, State 51, Line 1 Transaction (Process ID 57) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction. SQL script to create the tables and populate them with test data Create table TableA ( Id int identity primary key, Name nvarchar(50) ) Go Insert into TableA values ('Mark') Go Create table TableB ( Id int identity primary key, Name nvarchar(50) ) Go Insert into TableB values ('Mary') Go The following 2 transactions will result in a dead lock. Open 2 instances of SQL Server Management studio. From the first window execute Transaction 1 code and from the second window execute Transaction 2 code. -- Transaction 1 Begin Tran Update TableA Set Name = 'Mark Transaction 1' where Id = 1 -- From Transaction 2 window execute the first update statement Update TableB Set Name = 'Mary Transaction 1' where Id = 1 -- From Transaction 2 window execute the second update statement Commit Transaction -- Transaction 2 Begin Tran Update TableB Set Name = 'Mark Transaction 2' where Id = 1 -- From Transaction 1 window execute the second update statement Update TableA Set Name = 'Mary Transaction 2' where Id = 1 -- After a few seconds notice that one of the transactions complete -- successfully while the other transaction is made the deadlock victim Commit Transaction Next Video : We will discuss the criteria SQL Server uses to choose a deadlock victim
Views: 58114 kudvenkat
Oracle Database Tutorial - Deadlock in Oracle
 
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This video tutorial on Oracle on Oracle database provides detailed information about what is deadlock, how to analyze deadlock issue and how to fix dead lock issue. You can visit Oracle Database related videos here : https://www.youtube.com/watch?v=cDqlT7O8H0Q&list=PLRt-r4QiDOMfMmVU-8145pLcBxIdvAt8f&index=1 Website: http://guru4technoworld.wix.com/technoguru Facebook : https://www.facebook.com/a2zoftech/ Blog: http://dronatechnoworld.blogspot.com
Views: 31 Sandip M
PL/SQL: Locks
 
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In this tutorial, you'll learn the types of locks & how locks occurs while executing a query.
Views: 7814 radhikaravikumar
Difference between blocking and deadlocking
 
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deadlock vs blocking sql server In this video we will discuss the difference between blocking and deadlocking. This is one of the common SQL Server interview question. Let us understand the difference with an example. SQL Script to create the tables and populate them with test data Create table TableA ( Id int identity primary key, Name nvarchar(50) ) Go Insert into TableA values ('Mark') Go Create table TableB ( Id int identity primary key, Name nvarchar(50) ) Go Insert into TableB values ('Mary') Go Blocking : Occurs if a transaction tries to acquire an incompatible lock on a resource that another transaction has already locked. The blocked transaction remains blocked until the blocking transaction releases the lock. Example : Open 2 instances of SQL Server Management studio. From the first window execute Transaction 1 code and from the second window execute Transaction 2 code. Notice that Transaction 2 is blocked by Transaction 1. Transaction 2 is allowed to move forward only when Transaction 1 completes. --Transaction 1 Begin Tran Update TableA set Name='Mark Transaction 1' where Id = 1 Waitfor Delay '00:00:10' Commit Transaction --Transaction 2 Begin Tran Update TableA set Name='Mark Transaction 2' where Id = 1 Commit Transaction Deadlock : Occurs when two or more transactions have a resource locked, and each transaction requests a lock on the resource that another transaction has already locked. Neither of the transactions here can move forward, as each one is waiting for the other to release the lock. So in this case, SQL Server intervenes and ends the deadlock by cancelling one of the transactions, so the other transaction can move forward. Example : Open 2 instances of SQL Server Management studio. From the first window execute Transaction 1 code and from the second window execute Transaction 2 code. Notice that there is a deadlock between Transaction 1 and Transaction 2. -- Transaction 1 Begin Tran Update TableA Set Name = 'Mark Transaction 1' where Id = 1 -- From Transaction 2 window execute the first update statement Update TableB Set Name = 'Mary Transaction 1' where Id = 1 -- From Transaction 2 window execute the second update statement Commit Transaction -- Transaction 2 Begin Tran Update TableB Set Name = 'Mark Transaction 2' where Id = 1 -- From Transaction 1 window execute the second update statement Update TableA Set Name = 'Mary Transaction 2' where Id = 1 -- After a few seconds notice that one of the transactions complete -- successfully while the other transaction is made the deadlock victim Commit Transaction Link for all dot net and sql server video tutorial playlists https://www.youtube.com/user/kudvenkat/playlists?sort=dd&view=1 Link for slides, code samples and text version of the video http://csharp-video-tutorials.blogspot.com/2015/09/difference-between-blocking-and.html
Views: 69335 kudvenkat
TSQL: Transaction (Process ID n) Was Deadlocked On Lock Resources With Another Process and Has ...
 
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Full error: "Transaction (Process ID n) Was Deadlocked On Lock Resources With Another Process and Has Been Chosen As The Deadlock Victim. Rerun The Transaction." Previous video about blocking: https://www.youtube.com/watch?v=DPVGyyNw2iU
Views: 1606 SQLInSix Minutes
Oracle DB - What is ORA-01555
 
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Oracle DB - What is ORA-01555 Watch More Videos at: https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Parth Panjabi, Tutorials Point India Private Limited
Oracle Forms opening slowly Troubleshooting
 
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https://amzn.to/2Ph2CbI [affiliate link] We are back again with some issues and solutions. Actually one of my friends asked me regarding performance tuning if forms are opening slow. That time I gave him some ideas and promised him that I will back very soon with some more information. There are lots of factors which may impact the applications but there are some work around which can helpful fixed the issues. One more thing I would like to tell, friends I shared my knowledge’s as per my real time experiences and real life experiences. So, there is not like just copying and pasting the stuff. As already I have shared my real life time stories which I have learned from my life. So, let’s start now. Suppose, our forms are opening slow then what things we should be check and how to debug it. I will try to explain here and share my knowledge. I am sure; it will be useful because it’s having been experienced. 1. We should check which forms are opening slowly either any particular form or all forms. 2. If all forms are opening slowly for particular machine then clear the cache and try again. It can be machine speed slow, machine hardware and bandwidth speed. If all forms are opening slow and for all machine then we really need to check below things such as: A. Check whether Trace is enabled or disabled and if it is enabled then kindly disabled it. B. Check the top commands if any resources are consuming high CPU usage. C. Check for all Inactive Sessions if it’s there then kill those sessions. D. Check for deadlocks. E. Every user should close the forms and logout properly. But actually we don’t care. We just close windows tab at a time and left for break :D :P but that’s also impact our EBS internally. F. A programmer if ran any program with infinite loops then this also cause a performance issue. That’s why we need to write any program carefully. If program not properly then it may cause deadlock as also which I have explained it in my previous posts. G. It can also be because of increasing the number of users. Also need to check users have one active session. H. Check for the Performance Pack (Native I/O) is turned on for WLS. And most and always we use this method. If the users have issue for any custom forms then we should follow below steps which are easy and very effective. When he run the program that time you should follow below steps: 1. Enable the Trace file. Login to front-end - Help - Diagnostics - Trace - "Trace with Binds and waits” . Then there will be a trace file generate under below patch: $cd $ORACLE_HOME/admin/$CONTEXT_NAME/udump Now you can run either Trace Analyzer or tkprof as shown below commands: Trace Analyzer command: $sqlplus apps/apps_password SQL START TRCANLZR.sql UDUMP ora-data_ora1919.trc; TKPROF command: $ORACLE_HOME/admin/$CONTEXT_NAME/udump $tkprof ora-data_ora_1919.trc ora-data_ora_1919.txt explain=apps/apps_pwd Hope this may useful and helpful. We will come back again with new troubleshooting and solution as what we should do if forms opening slow after increasing the number of session. For any concerns or suggestions please reach to us either by comment box or contact us @ ora-data.blogspot.com.
Views: 1419 ORACLE SUPPORT
MSSQL - How to Handle and Retry Deadlocks
 
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Example Code below --===================================== -- Windows/Session #1 --===================================== SELECT @@SPID IF EXISTS (SELECT 1 FROM sys.tables WHERE name = 'SampleTable') DROP TABLE SampleTable CREATE TABLE [SampleTable] ( [Id] [int] IDENTITY(1,1) NOT NULL, [Name] [varchar](100) NULL, [Value] [varchar](100) NULL, [DateChanged] [datetime] DEFAULT(GETDATE()) NULL, CONSTRAINT [PK_SampleTable] PRIMARY KEY CLUSTERED ([Id] ASC) ) INSERT INTO SampleTable(Name, Value) SELECT 'Name1', 'Value1' UNION ALL SELECT 'Name2', 'Value2' UNION ALL SELECT 'Name3', 'Value3' SELECT * FROM SampleTable --===================================== -- Windows/Session #2 --===================================== ----------------------------------------------------- -- This window/session is default CASE DEADLOCK -- ----------------------------------------------------- SET DEADLOCK_PRIORITY LOW BEGIN TRAN UPDATE SampleTable SET Name = Name + Name WHERE ID=2 WAITFOR DELAY '00:00:10' UPDATE SampleTable SET Name = Name + Name WHERE ID=1 COMMIT TRAN --===================================== -- Windows/Session #3 --===================================== ----------------------------------------------------- -- This window/session is default CASE DEADLOCK -- ----------------------------------------------------- SET DEADLOCK_PRIORITY NORMAL BEGIN TRAN UPDATE SampleTable SET Name = Name + Name WHERE ID=1 WAITFOR DELAY '00:00:10' UPDATE SampleTable SET Name = Name + Name WHERE ID=2 COMMIT TRAN --===================================== -- Windows/Session #4 --===================================== ----------------------------------------------------- -- This Is a Retry Block Template for -- INSERT/UPDATE/DELETE Scenarios ----------------------------------------------------- SET DEADLOCK_PRIORITY LOW DECLARE @RETRY_COUNT_CURRENT INT DECLARE @RETRY_COUNT_MAXIMUM INT DECLARE @ERROR_NUM INT DECLARE @ERROR_MSG NVARCHAR(MAX) SET @ERROR_NUM = 0 SET @RETRY_COUNT_CURRENT = 0 SET @RETRY_COUNT_MAXIMUM = 3 WHILE @RETRY_COUNT_CURRENT lessthan @RETRY_COUNT_MAXIMUM BEGIN BEGIN TRANSACTION BEGIN TRY UPDATE SampleTable SET Name = Name + Name WHERE ID=2 WAITFOR DELAY '00:00:10' UPDATE SampleTable SET Name = Name + Name WHERE ID=1 COMMIT BREAK END TRY BEGIN CATCH SELECT @ERROR_NUM = ERROR_NUMBER(), @ERROR_MSG = ERROR_MESSAGE() PRINT @ERROR_MSG PRINT @ERROR_NUM ROLLBACK SET @RETRY_COUNT_CURRENT = @RETRY_COUNT_CURRENT + 1 WAITFOR DELAY '00:00:05' CONTINUE END CATCH; END --===================================== -- Windows/Session #5 --===================================== ----------------------------------------------------- -- This Is a Retry Block Template for SELECT victims -- SELECTs can be deadlock victims, in which case you -- have to buffer/restrict the ResultSet of the dead -- lock run, then retry, this requires temp tables ----------------------------------------------------- SET DEADLOCK_PRIORITY LOW DECLARE @RETRY_COUNT_CURRENT INT DECLARE @RETRY_COUNT_MAXIMUM INT DECLARE @ERROR_NUM INT DECLARE @ERROR_MSG NVARCHAR(MAX) SET @ERROR_NUM = 0 SET @RETRY_COUNT_CURRENT = 0 SET @RETRY_COUNT_MAXIMUM = 3 -- Buffer the output, in order to clear the buffer in case of deadlock -- This is required to suppress any streaming output to the caller CREATE TABLE #TABLE_01 ( Id INT, Name VARCHAR(100), Value VARCHAR(100), CreatedOn DATETIME ) WHILE @RETRY_COUNT_CURRENT lessthan @RETRY_COUNT_MAXIMUM BEGIN BEGIN TRANSACTION BEGIN TRY TRUNCATE TABLE #TABLE_01 INSERT INTO #TABLE_01 SELECT * FROM SampleTable COMMIT SELECT * FROM #TABLE_01 BREAK END TRY BEGIN CATCH SELECT @ERROR_NUM = ERROR_NUMBER(), @ERROR_MSG = ERROR_MESSAGE() PRINT @ERROR_MSG PRINT @ERROR_NUM ROLLBACK SET @RETRY_COUNT_CURRENT = @RETRY_COUNT_CURRENT + 1 WAITFOR DELAY '00:00:05' CONTINUE END CATCH; END
Views: 1133 CodeCowboyOrg
Find Blocking Session and Release Immediately in Oracle
 
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Find Blocking Session and Release Immediately in Oracle
Views: 264 Sendi Channel
Hints and Tips - Avoiding never ending locks - part 1
 
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Row locking is a critical component of ensuring the integrity of your data inside the database. But locks of extended duration can easily create system-wide problems in your applications. This quick tip gives you some ideas for handling locks better. ====================================================== Copyright © 2015 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.
Views: 1085 Connor McDonald
How to fix deadlocks with SQLGrease
 
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See how SQLGrease helps identify and provide all the details necessary to fix a SQL Server deadlock. Visit us at www.sqlgrease.com for a free 7 day trial. No credit card required.
Views: 464 SQLGrease
Deadlock solution
 
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Aizat Abdullah ft Khairil Azri
Views: 89 Aizat Abdullah
Oracle database locking issue
 
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Analyzing locks with d.side - Automatic diagnostic for Oracle databases performance and troubleshooting http://www.dside-software.com Copyright (c) d.side software
Views: 259 D.SIDE SOFTWARE
What does the error snapshot too old mean
 
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What does the error snapshot too old mean - Find out more explanation for : 'What does the error snapshot too old mean' only from this channel. Information Source: google
Views: 78 el ubuntu2
Can you really flush Oracle SHARED POOL
 
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This video will explain what happens in reality when you issue ALTER SYSTEM FLUSH SHARED_POOL. A step by step case study will give you the answers by the end of this video session. Oracle DBA training: Need some training on Performance tuning? - Whatsapp +919951696808 Look for more contents on training at: www.orskl.com/training
Views: 2779 OrSkl Academy
Oracle DBA - Solve Long Running Query & TX Row Lock Contention | Performance Tuning
 
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How to Solve Row Lock Contention in Oracle Database - Performance Tuning - Oracle DBA Solve Row Lock Contention & Long Running Query in Oracle Database - Performance Tuning Oracle DBA - Performance Tuning Row Lock Contention Please Like, Comment, Subscribe and Share... Boxcut Media.
Views: 5658 BoxCut Media
How to manager Oracle database locks and deadlocks with Oracle Enterprise Manager 12C
 
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Video tutorials on How to manager Oracle database locks and deadlocks with Oracle Enterprise Manager 12C For more Database Administration articles and scripts go to www.aodba.com & www.verticablog.com More Articles, Scripts and How-To Papers on http://www.aodba.com
Views: 3153 AO DBA
DB & SQL – Abschnitt 12.6: Deadlock
 
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Dieses Begleitvideo zum Buch ›Datenbanken & SQL‹ (http://lulu.com/spotlight/matthias_wolf) zeigt die Situation, in der ein ›Deadlock‹ auftritt und wie der Datenbankserver diesen Knoten einfach zerschlägt, indem eine der beteiligten Transaktionen automatisch zurückgerollt wird.
Views: 463 Matthias Wolf
Solving Performance Problems on Oracle DB
 
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Solving Performance Problems on Oracle DB Matthew Vegh - Embarcadero Thursday, June 26, 2014 - 11am DBAs and database developers regularly spend a lot of time tracking down and resolving performance issues on the database servers they are responsible for; it can be very difficult, frustrating, and expensive. Given the complex interactions of applications, users and databases, new performance issues can arise almost as fast as old ones can be addressed. This session will simulate common performance problems on an Oracle server and then both identify those problems and provide effective solutions. Matthew Vegh is a Software Architect at Embarcadero Technologies for the Embarcadero DB Power Studio family of products and has been with the company for the better part of a decade. He has over 15 years of development experience with a wide range of technologies and a definite preference for database tooling.
Deadlock transaction in a database with one table - PostgreSQL
 
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No sound was recorded. PostgreSQL 10.0 For Oracle see https://youtu.be/l2IGoaWql64 Output from process: ERROR: deadlock detected DETAIL: Process 5883 waits for ShareLock on transaction 574; blocked by process 5791. Process 5791 waits for ShareLock on transaction 573; blocked by process 5883. HINT: See server log for query details. CONTEXT: while updating tuple (0,20) in relation "t" === create table t (i int, n int); insert into t values(1,10),(2,20); === A select * from t; begin; update t set n=n+1 where i=1; B begin; update t set n=n+1 where i=2; update t set n=n+1 where i=1; A update t set n=n+1 where i=1; B commit; A commit;
Views: 143 chlordk
How to create a DB deadlock situation and a session recovery
 
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This Video KB shows how to create a database deadlock siutation using a database client and a PowerCenter workflow, and then recover the workflow. ​
Views: 1131 Informatica Support
Ask Tom Office Hours: PL/SQL Error Management
 
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In our March 2018 session, we explored error management, from raising to handling exceptions. We took a look at SAVE EXCEPTION with FORALL, LOG ERRORS, when it makes sense to "swallow up" an exception - though preferably not with WHEN OTHERS THEN NULL. AskTOM Office Hours offers free, monthly training and tips on how to make the most of Oracle Database, from Oracle product managers, developers and evangelists. https://asktom.oracle.com/ Oracle Developers portal: https://developer.oracle.com/ Sign up for an Oracle Cloud trial: https://cloud.oracle.com/en_US/tryit music: bensound.com
Views: 317 Oracle Developers
Deadlock transaction in a database with one table - Oracle
 
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No sound was recorded. Oracle 12.1. For PostgreSQL see https://youtu.be/En8EFv90yCc To avoid inconsistency, type "SET AUTOCOMMIT OFF" and "WHENEVER SQLERROR EXIT ROLLBACK" at the top. Otherwise only a part of the transaction will be commited. === A select * from t; update t set n=n+1 where i=1; B update t set n=n+1 where i=2; update t set n=n+1 where i=1; A update t set n=n+1 where i=2; B commit; A commit; select * from t;
Views: 27 chlordk
MSSQL - Understanding and Deciphering a Deadlock Graph XML
 
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Best Most Useful Links for Understand a Deadlock (XML) in SQL Server 1) Compatible Locks Table - http://technet.microsoft.com/en-us/library/ms186396(v=sql.105).aspx 2) Understanding Deadlocks - https://www.simple-talk.com/sql/performance/sql-server-deadlocks-by-example/ In your example waitresource="KEY: 6:72057594090487808 (d900ed5a6cc6) 1) Database - retrieve the database involved in the deadlock with SELECT * FROM sys.databases WHERE database_id IN (6) 2) Table or Index - retrieve the table or index involved in the deadlock SELECT b.name AS TableName, c.name AS IndexName, c.type_desc AS IndexType, * FROM sys.partitions a INNER JOIN sys.objects b ON a.object_id = b.object_id INNER JOIN sys.indexes c ON a.object_id = c.object_id AND a.index_id = c.index_id WHERE partition_id IN ('72057594090487808') 3) Exact Row - retrieve the exact row or page, in your specific case the wait resource was a KEY, so you search the "column" %%lockres%% (yes the column name is actually %%lockres%%). If your table is not too out of date or if it is not a DELETE operation, then you will find the exact row from that hash, after you have determined which table that "partition id" or "hobt_id" is from then alter and run the below code (disclaimer - the hashes and page locations may have changed by the time you are doing the debugging, though unlikely with the key hashes) SELECT sys.fn_PhysLocFormatter(%%physloc%%) AS PageResource, %%lockres%% AS LockResource, * FROM InsertTableNameFromStep2Here WHERE %%lockres%% IN ('(d900ed5a6cc6)') Keep in mind that usually 2 resources are conflicting which caused the deadlock. However, it doesn't necessarily have to be both of the statements provided in the deadlock graph which is doing both of the locking. It is also possible that a statement prior, but within the same transaction (but not identified in the deadlock graph) locked 1 of the 2 resources. But 1 of the 2 statements in the deadlock is definitely involved in locking 1 of the 2 resources causing the deadlock at the time the deadlock was logged.
Views: 7446 CodeCowboyOrg
Concorrencia Oracle
 
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neste vídeo vemos como funciona a concorrência de transações no Oracle. Apresentamos conceitos como LOCK, BLOCK e DEADLOCK
Views: 379 Eduardo Morelli
Blocking and Deadlocks Troubleshooting in SQL Server
 
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SQL Server Concurrency Model is, perhaps, the most confusing and least understood part of SQL Server Internals. Blocking issues and deadlocks occur unexpectedly and negatively impact performance and user experience in the systems. Nevertheless, this model is well-structured and easy to understand when you analyze it from lock types and their lifetime and compatibility standpoint. This, two-part session will explain why blocking and deadlocks occur and how to troubleshoot them in your environments. First, it will provide the overview of SQL Server Concurrency Model and describe SQL Server locking behavior and root-causes of typical blocking issues. Next, the session will discuss how to capture and troubleshoot them using standard SQL Server tools, and how to simplify the analysis using Blocking Monitoring Framework developed by Dmitri.
Oracle Tutorial || Oracle|Adv Sql |online training|| Table Locks Part - 1 by basha
 
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DURGASOFT is INDIA's No.1 Software Training Center offers online training on various technologies like JAVA, .NET , ANDROID,HADOOP,TESTING TOOLS ,ADF,INFORMATICA,TABLEAU,IPHONE,OBIEE,ANJULAR JS, SAP... courses from Hyderabad & Bangalore -India with Real Time Experts. Mail us your requirements to [email protected] so that our Supporting Team will arrange Demo Sessions. Ph:Call +91-8885252627,+91-7207212428,+91-7207212427,+91-8096969696. http://durgasoft.com http://durgasoftonlinetraining.com https://www.facebook.com/durgasoftware http://durgajobs.com https://www.facebook.com/durgajobsinfo......
MySQL Deadlock Situation
 
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In the eighth episode of the 'Getting Started with MySQL' series, we saw some demonstrations on the Transaction capabilities of InnoDB Storage Engine in MySQL. We also understood the role of 'tx_isolation' variable in MySQL Transaction. Now in this short episode, we'll see how MySQL overcomes a Deadlock situation. When two Transactions wait for each other's lock, that ends up being a never ending wait. Such a situation (Deadlock) is handled automatically by MySQL, aborting one of those Transactions. One of the reasons why it is recommended to keep Transactions short (with only a few set of statements) is avoid situations when a Deadlock occurs and a lengthy Transaction gets aborted.
Views: 1509 Rajesh Rajasekharan
Oracle Database Hang Manager
 
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In our September 2018 session, Mark Scardina welcomes Walter Battistella who was responsible for developing the Oracle Hang Management feature that provides autonomous detection and resolution of hangs and deadlocks in Oracle databases. Questions ranged across the full gambit of design, functionality and best its availability in Oracle Database Cloud Services. 02:30 What is Oracle’s goal in developing Hang Manager? 03:45 What actually is a session hang? 05:35 What causes a process or session to be hung? 07:21 Are deadlocks the same as hung sessions or do they differ? 09:40 Do I need to enable hang manager and if so how? 10:17 Which versions and deployment types have Hang Manager enabled? 12:30 How does Hang Manager resolve hangs? 15:20 What is the overhead of Hang Manager monitoring these sessions? 18:00 Is Hang Manager in the transaction path? 18:22 How do I know Hang Manager has detected and resolved a hang or deadlock? 21:22 How can I get notifications when a hang or deadlock is resolved? 23:15 Are these notifications available in Enterprise Manager? 24:00 Does Hang Manager resolve all hangs and deadlocks? 28:51 I thought Oracle Database already resolved deadlocks prior to 18.1. What is different that Hang Manager does? 31:30 If I have a critical application , can I speed up the resolution time? 34:54 I understand that QoS Management lets be set the criticality of workloads. Does Hang Manager use that information? 37:47 Does Hang Manager monitor PQ sessions as well? If so how does its resolution impact the main session? 39:15 Does Hang Manager detect and resolve hangs in ASM? 44:56 Is Hang Manager running on the Oracle Autonomous DB? 45:22 Does it run in the Oracle Database Cloud Service? AskTOM Office Hours offers free, monthly training and tips on how to make the most of Oracle Database, from Oracle product managers, developers and evangelists. https://asktom.oracle.com/ Oracle Developers portal: https://developer.oracle.com/ Sign up for an Oracle Cloud trial: https://cloud.oracle.com/en_US/tryit Music by bensound.com
Views: 84 Oracle Developers
Oracle Midlands #13: All About Table Locks - Franck Pachot
 
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Timestamps: 0:45 - Basics 5:03 - TX lock demo 9:30 - TM lock info 21:04 - Foreign key index demo 28:48 - 10g, 11g, 12c locking differences 41:50 - New online operations in 12c 46:26 - Event 10704 trace 50:34 - Deadlock demo 53:42 - Q&A Franck discusses different types of locking scenarios to consider with your systems. The slides are available at: Google: https://drive.google.com/folderview?id=0B0DLaAfeW6uKZmJ3TXE0WGtLYlE Dropbox: https://www.dropbox.com/sh/9koxoemak8ts7j6/AADozVVYLoK_FdDZbQGC6TYta This event was sponsored by Red Stack Technology (http://redstacktechnology.com/). See more events at http://OracleMidlands.com/ Copyright Disclaimer Under Section 107 of the Copyright Act 1976, allowance is made for fair use for purposes such as criticism, comment, news reporting, teaching, scholarship, and research. Fair use is a use permitted by copyright statute that might otherwise be infringing. Non-profit, educational or personal use tips the balance in favor of fair use. "Fair Dealing" under UK Copyright, Designs and Patents Act 1988.
Views: 723 Oracle Midlands
SQL Server Deadlocks
 
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Video talks about SQL Server Deadlocks Deadlocks in sql server locks in sql server deadlock in sql server deadlock prevention deadlock victim Also part of Step by step SQL Training videos SQL Tutorial More videos are at : https://www.youtube.com/channel/UCgWvQ6cBxZwABl_hL48ayXg
Views: 772 Training2SQL MSBI
02 Shared Lock & Exclusive Lock In oracle database table lock
 
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Purpose Use the LOCK TABLE statement to lock one or more tables, table partitions, or table subpartitions in a specified mode. This lock manually overrides automatic locking and permits or denies access to a table or view by other users for the duration of your operation. Some forms of locks can be placed on the same table at the same time. Other locks allow only one lock for a table. A locked table remains locked until you either commit your transaction or roll it back, either entirely or to a savepoint before you locked the table. A lock never prevents other users from querying the table. A query never places a lock on a table. Readers never block writers and writers never block readers. See Also: Oracle Database Concepts for a complete description of the interaction of lock modes COMMIT ROLLBACK SAVEPOINT Prerequisites The table or view must be in your own schema or you must have the LOCK ANY TABLE system privilege, or you must have any object privilege on the table or view. ROW SHARE ROW SHARE permits concurrent access to the locked table but prohibits users from locking the entire table for exclusive access. ROW SHARE is synonymous with SHARE UPDATE, which is included for compatibility with earlier versions of Oracle Database. ROW EXCLUSIVE ROW EXCLUSIVE is the same as ROW SHARE, but it also prohibits locking in SHARE mode. ROW EXCLUSIVE locks are automatically obtained when updating, inserting, or deleting. SHARE UPDATE See ROW SHARE. SHARE SHARE permits concurrent queries but prohibits updates to the locked table. SHARE ROW EXCLUSIVE SHARE ROW EXCLUSIVE is used to look at a whole table and to allow others to look at rows in the table but to prohibit others from locking the table in SHARE mode or from updating rows. EXCLUSIVE EXCLUSIVE permits queries on the locked table but prohibits any other activity on it. NOWAIT Specify NOWAIT if you want the database to return control to you immediately if the specified table, partition, or table subpartition is already locked by another user. In this case, the database returns a message indicating that the table, partition, or subpartition is already locked by another user. WAIT Use the WAIT clause to indicate that the LOCK TABLE statement should wait up to the specified number of seconds to acquire a DML lock. There is no limit on the value of integer. If you specify neither NOWAIT nor WAIT, then the database waits indefinitely until the table is available, locks it, and returns control to you. When the database is executing DDL statements concurrently with DML statements, a timeout or deadlock can sometimes result. The database detects such timeouts and deadlocks and returns an error.
Views: 797 OnLinE ReSoUrCe
Sql server 2016 Tutorial-Locks, blocking, and deadlocks-part 13
 
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Sql server 2016 Tutorial-Locks, blocking, and deadlocks-part 13
Views: 2223 kumaran kumaran
Oracle Database Lock Mode
 
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Tipe – tipe lock yang terdapat di oracle database
Views: 175 Muhammad Umar
Tutorial 23 : TRIGGER MUTATION ERROR (Part 2) || How to overcome on TRIGGER MUTATION ERROR.
 
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Hi Friends, Here we are learning about, how we can TRIGGER MUTATION ERROR. Hope the concept and example would be clear to you. For any confusion or doubt, let me know in comment box. Link for TRIGGER Introduction : https://youtu.be/zKBoAAmJx1c Link where DML TRIGGER explained : https://youtu.be/VURsVTBF8lw Link of INSTEAD-OF INSERT Trigger : https://youtu.be/BzTd3LSNmbQ Link of INSTEAD-OF UPDATE Trigger : https://youtu.be/DEQ7kT5ju-U Link of INSTEAD-OF DELETE Trigger : https://youtu.be/mSTiChGnNME Link of STATEMENT LEVEL TRIGGER in Oracle : https://youtu.be/yULPUsMXfJo Link of TRIGGER MUTATION ERROR (Part 1) : https://youtu.be/vVltTr0VCbQ About Me : https://about.me/saurabhsagarsinha Thanks, Happy Coding :)
Views: 90 YourSmartCode
What is SQL Deadlock | Sql Deadlock example | Dbms Interview Questions
 
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Deadlock is a unique situation in a multi user system that causes two or more users to wait indefinitely for a locked resource or many resource.sql deadlock example , sql deadlock solution , sql deadlock detector , sql deadlock trace , transactsql sql job deadlock , error sql job deadlock , sql avoid deadlock , sql transactions deadlock , what causes a deadlock in sql , what is deadlock in sql server with example , deadlock situation in sql server , deadlock errors in sql server , dbms interview questions in tcs , dbms queries interview questions For more details visit: http://www.wikitechy.com/ Facebook: https://www.facebook.com/wikitechy Twitter: https://twitter.com/WikitechyCom Google Plus: https://plus.google.com/u/0/b/108939953321929485284/108939953321929485284/posts Linked in : https://www.linkedin.com/company/wikitechy Pinterest: https://www.pinterest.com/wikitechy/ Tumblr: http://wikitechy.tumblr.com/
03 Dead Lock in oracle database
 
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DML Locks DML locks or data locks guarantee the integrity of data being accessed concurrently by multiple users. DML locks help to prevent damage caused by interference from simultaneous conflicting DML or DDL operations. By default, DML statements acquire both table-level locks and row-level locks. The reference for each type of lock or lock mode is the abbreviation used in the Locks Monitor from Oracle Enterprise Manager (OEM). For example, OEM might display TM for any table lock within Oracle rather than show an indicator for the mode of table lock (RS or SRX). Row Locks (TX) Row-level locks serve a primary function to prevent multiple transactions from modifying the same row. Whenever a transaction needs to modify a row, a row lock is acquired by Oracle. There is no hard limit on the exact number of row locks held by a statement or transaction. Also, unlike other database platforms, Oracle will never escalate a lock from the row level to a coarser granular level. This row locking ability provides the DBA with the finest granular level of locking possible and, as such, provides the best possible data concurrency and performance for transactions. The mixing of multiple concurrency levels of control and row level locking means that users face contention for data only whenever the same rows are accessed at the same time. Furthermore, readers of data will never have to wait for writers of the same data rows. Writers of data are not required to wait for readers of these same data rows except in the case of when a SELECT... FOR UPDATE is used. Writers will only wait on other writers if they try to update the same rows at the same point in time. In a few special cases, readers of data may need to wait for writers of the same data. For example, concerning certain unique issues with pending transactions in distributed database environments with Oracle. Transactions will acquire exclusive row locks for individual rows that are using modified INSERT, UPDATE, and DELETE statements and also for the SELECT with the FOR UPDATE clause. Modified rows are always locked in exclusive mode with Oracle so that other transactions do not modify the row until the transaction which holds the lock issues a commit or is rolled back. In the event that the Oracle database transaction does fail to complete successfully due to an instance failure, then Oracle database block level recovery will make a row available before the entire transaction is recovered. The Oracle database provides the mechanism by which row locks acquire automatically for the DML statements mentioned above. Whenever a transaction obtains row locks for a row, it also acquires a table lock for the corresponding table. Table locks prevent conflicts with DDL operations that would cause an override of data changes in the current transaction. Table Locks (TM) What are table locks in Oracle? Table locks perform concurrency control for simultaneous DDL operations so that a table is not dropped in the middle of a DML operation, for example. When Oracle issues a DDL or DML statement on a table, a table lock is then acquired. As a rule, table locks do not affect concurrency of DML operations. Locks can be acquired at both the table and sub-partition level with partitioned tables in Oracle. A transaction acquires a table lock when a table is modified in the following DML statements: INSERT, UPDATE, DELETE, SELECT with the FOR UPDATE clause, and LOCK TABLE. These DML operations require table locks for two purposes: to reserve DML access to the table on behalf of a transaction and to prevent DDL operations that would conflict with the transaction. Any table lock prevents the acquisition of an exclusive DDL lock on the same table, and thereby prevents DDL operations that require such locks. For example, a table cannot be altered or dropped if an uncommitted transaction holds a table lock for it. A table lock can be held in any of several modes: row share (RS), row exclusive (RX), share (S), share row exclusive (SRX), and exclusive (X). The restrictiveness of a table lock's mode determines the modes in which other table locks on the same table can be obtained and held.
Views: 232 OnLinE ReSoUrCe
SQL Server deadlock victim selection
 
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Text version of the video http://csharp-video-tutorials.blogspot.com/2015/08/sql-server-deadlock-victim-selection.html Slides http://csharp-video-tutorials.blogspot.com/2015/08/sql-server-deadlock-victim-selection_26.html All SQL Server Text Articles http://csharp-video-tutorials.blogspot.com/p/free-sql-server-video-tutorials-for.html All SQL Server Slides http://csharp-video-tutorials.blogspot.com/p/sql-server.html All Dot Net and SQL Server Tutorials in English https://www.youtube.com/user/kudvenkat/playlists?view=1&sort=dd All Dot Net and SQL Server Tutorials in Arabic https://www.youtube.com/c/KudvenkatArabic/playlists In this video we will discuss 1. How SQL Server detects deadlocks 2. What happens when a deadlock is detected 3. What is DEADLOCK_PRIORITY 4. What is the criteria that SQL Server uses to choose a deadlock victim when there is a deadlock This is continuation to Part 78, please watch Part 78 before proceeding. How SQL Server detects deadlocks Lock monitor thread in SQL Server, runs every 5 seconds by default to detect if there are any deadlocks. If the lock monitor thread finds deadlocks, the deadlock detection interval will drop from 5 seconds to as low as 100 milliseconds depending on the frequency of deadlocks. If the lock monitor thread stops finding deadlocks, the Database Engine increases the intervals between searches to 5 seconds. What happens when a deadlock is detected When a deadlock is detected, the Database Engine ends the deadlock by choosing one of the threads as the deadlock victim. The deadlock victim's transaction is then rolled back and returns a 1205 error to the application. Rolling back the transaction of the deadlock victim releases all locks held by that transaction. This allows the other transactions to become unblocked and move forward. What is DEADLOCK_PRIORITY By default, SQL Server chooses a transaction as the deadlock victim that is least expensive to roll back. However, a user can specify the priority of sessions in a deadlock situation using the SET DEADLOCK_PRIORITY statement. The session with the lowest deadlock priority is chosen as the deadlock victim. Example : SET DEADLOCK_PRIORITY NORMAL DEADLOCK_PRIORITY 1. The default is Normal 2. Can be set to LOW, NORMAL, or HIGH 3. Can also be set to a integer value in the range of -10 to 10. LOW : -5 NORMAL : 0 HIGH : 5 What is the deadlock victim selection criteria 1. If the DEADLOCK_PRIORITY is different, the session with the lowest priority is selected as the victim 2. If both the sessions have the same priority, the transaction that is least expensive to rollback is selected as the victim 3. If both the sessions have the same deadlock priority and the same cost, a victim is chosen randomly SQL Script to setup the tables for the examples Create table TableA ( Id int identity primary key, Name nvarchar(50) ) Go Insert into TableA values ('Mark') Insert into TableA values ('Ben') Insert into TableA values ('Todd') Insert into TableA values ('Pam') Insert into TableA values ('Sara') Go Create table TableB ( Id int identity primary key, Name nvarchar(50) ) Go Insert into TableB values ('Mary') Go Open 2 instances of SQL Server Management studio. From the first window execute Transaction 1 code and from the second window execute Transaction 2 code. We have not explicitly set DEADLOCK_PRIORITY, so both the sessions have the default DEADLOCK_PRIORITY which is NORMAL. So in this case SQL Server is going to choose Transaction 2 as the deadlock victim as it is the least expensive one to rollback. -- Transaction 1 Begin Tran Update TableA Set Name = Name + ' Transaction 1' where Id IN (1, 2, 3, 4, 5) -- From Transaction 2 window execute the first update statement Update TableB Set Name = Name + ' Transaction 1' where Id = 1 -- From Transaction 2 window execute the second update statement Commit Transaction -- Transaction 2 Begin Tran Update TableB Set Name = Name + ' Transaction 2' where Id = 1 -- From Transaction 1 window execute the second update statement Update TableA Set Name = Name + ' Transaction 2' where Id IN (1, 2, 3, 4, 5) -- After a few seconds notice that this transaction will be chosen as the deadlock -- victim as it is less expensive to rollback this transaction than Transaction 1 Commit Transaction In the following example we have set DEADLOCK_PRIORITY of Transaction 2 to HIGH. Transaction 1 will be chosen as the deadlock victim, because it's DEADLOCK_PRIORITY (Normal) is lower than the DEADLOCK_PRIORITY of Transaction 2. -- Transaction 1 Begin Tran Update TableA Set Name = Name + ' Transaction 1' where Id IN (1, 2, 3, 4, 5) -- From Transaction 2 window execute the first update statement Update TableB Set Name = Name + ' Transaction 1' where Id = 1 -- From Transaction 2 window execute the second update statement Commit Transaction
Views: 39573 kudvenkat
01 Oracle database Table lock
 
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Purpose Use the LOCK TABLE statement to lock one or more tables, table partitions, or table subpartitions in a specified mode. This lock manually overrides automatic locking and permits or denies access to a table or view by other users for the duration of your operation. Some forms of locks can be placed on the same table at the same time. Other locks allow only one lock for a table. A locked table remains locked until you either commit your transaction or roll it back, either entirely or to a savepoint before you locked the table. A lock never prevents other users from querying the table. A query never places a lock on a table. Readers never block writers and writers never block readers. See Also: Oracle Database Concepts for a complete description of the interaction of lock modes COMMIT ROLLBACK SAVEPOINT Prerequisites The table or view must be in your own schema or you must have the LOCK ANY TABLE system privilege, or you must have any object privilege on the table or view. ROW SHARE ROW SHARE permits concurrent access to the locked table but prohibits users from locking the entire table for exclusive access. ROW SHARE is synonymous with SHARE UPDATE, which is included for compatibility with earlier versions of Oracle Database. ROW EXCLUSIVE ROW EXCLUSIVE is the same as ROW SHARE, but it also prohibits locking in SHARE mode. ROW EXCLUSIVE locks are automatically obtained when updating, inserting, or deleting. SHARE UPDATE See ROW SHARE. SHARE SHARE permits concurrent queries but prohibits updates to the locked table. SHARE ROW EXCLUSIVE SHARE ROW EXCLUSIVE is used to look at a whole table and to allow others to look at rows in the table but to prohibit others from locking the table in SHARE mode or from updating rows. EXCLUSIVE EXCLUSIVE permits queries on the locked table but prohibits any other activity on it. NOWAIT Specify NOWAIT if you want the database to return control to you immediately if the specified table, partition, or table subpartition is already locked by another user. In this case, the database returns a message indicating that the table, partition, or subpartition is already locked by another user. WAIT Use the WAIT clause to indicate that the LOCK TABLE statement should wait up to the specified number of seconds to acquire a DML lock. There is no limit on the value of integer. If you specify neither NOWAIT nor WAIT, then the database waits indefinitely until the table is available, locks it, and returns control to you. When the database is executing DDL statements concurrently with DML statements, a timeout or deadlock can sometimes result. The database detects such timeouts and deadlocks and returns an error.
Views: 701 OnLinE ReSoUrCe
Oracle WebLogic Server & EBS R12.2 Q/A: JVM, Heap, GC, Stack, Thread Dump
 
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More details at http://k21academy.com/live13 We recently had a Masterclass on Oracle WebLogic Server covering What, Why & How at http://k21academy.com/weblogic02 in that webinar there were a lot of questions. Most of these questions were answered in Webinar however not all questions were covered because of time. We'll be adding these questions over a period of time in Private Facebook Group for WebLogic Server at http://k21academy.com/weblogicqa This post covers weekly live show on our Facebook Page at http://facebook.com/k21academy covering Oracle WebLogic Server and issues reported with WebLogic Server in Oracle EBS R12.2 asked in WebLogic Masterclass at http://k21academy.com/weblogic02 Question Asked "I am working on Oracle EBS R12.2.3, My Questions is that OACore managed server is going into warning state frequently. I've increased Java Heap Size from 1 GB to 2 GB but still getting the same error sometimes. After collecting Garbage, it will be OK, but want to resolve the issue permanently. Need You Guidance ... Q1: What would you do in a situation like this? Q2: What is JVM & Heap Size in JVM? Q3: How do you know what is Heap Size Value and How do you change the value of Heap from 1GB to 2 GB? Q4: What is Garbage Collection and How Often you should run it? Q5: What does parameter -Xms, -Xmx, -XX:PermSize, -XX:MaxPermSize mean when you start JVM? I've covered all this in this video Here is what Atul Covered in Weekly Live Show 00:00-8:18: Introduction & Welcome 8:18-15:47 What is WebLogic Server & Task Performed by WebLogic Admins 15:47-17:15 Q: Managed Server in EBS (R12) going in Warning State 17:15-30:06 Oracle E-Business Suite R12.2 Architecture, WebLogic Domain, Admin & Managed Server, Config Files for Domain in EBS R12.2 30:06 - 41:00 What is JVM, JVM Parameters like -Xms, -Xmx, -XX:PermSize, -XX:MaxPermSize, Garbage Collection - GC (Major / Minor), JVM Tuning Guidelines, Q/A 41:00- 50:00 Heap, Stack & Thread Dump, Warning State issue in EBS R12.2 for Managed Server 50:00-56:14 Wrap-Up and FREE Training Now back to the original question If you are in a situation like this, How would you troubleshoot or approach to fix the issue (Leave a comment and see If you can help others https://www.youtube.com/watch?v=Zmd96z-5qO0 More details at http://k21academy.com/live13
Views: 2510 K21Academy
COMMIT and ROLLBACK (Introduction to Oracle SQL)
 
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An explanation of what COMMIT and ROLLBACK is. The full Introduction to Oracle SQL course is available here: https://www.databasestar.com/introduction-to-oracle-sql-course/
Views: 1134 Database Star
Select statement and deadlock in SQL Server
 
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SELECT statement can participate in a deadlock situation in Microsoft SQL Server. It seems unnatural. Shouldn't SELECT lock nothing? This video explains how SELECT query is executed and why a deadlock may occur.
Views: 304 DBA presents
Oracle DB - Categories of Failure
 
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Oracle DB - Categories of Failure Watch More Videos at: https://www.tutorialspoint.com/videotutorials/index.htm Lecture By: Mr. Parth Panjabi, Tutorials Point India Private Limited
SQL: Transaction Part-1
 
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In this tutorial, you'll learn what are transaction and nature of transaction. PL/SQL (Procedural Language/Structured Query Language) is Oracle Corporation's procedural extension for SQL and the Oracle relational database. PL/SQL is available in Oracle Database (since version 7), TimesTen in-memory database (since version 11.2.1), and IBM DB2 (since version 9.7).[1] Oracle Corporation usually extends PL/SQL functionality with each successive release of the Oracle Database. PL/SQL includes procedural language elements such as conditions and loops. It allows declaration of constants and variables, procedures and functions, types and variables of those types, and triggers. It can handle exceptions (runtime errors). Arrays are supported involving the use of PL/SQL collections. Implementations from version 8 of Oracle Database onwards have included features associated with object-orientation. One can create PL/SQL units such as procedures, functions, packages, types, and triggers, which are stored in the database for reuse by applications that use any of the Oracle Database programmatic interfaces. PL/SQL works analogously to the embedded procedural languages associated with other relational databases. For example, Sybase ASE and Microsoft SQL Server have Transact-SQL, PostgreSQL has PL/pgSQL (which emulates PL/SQL to an extent), and IBM DB2 includes SQL Procedural Language,[2] which conforms to the ISO SQL’s SQL/PSM standard. The designers of PL/SQL modeled its syntax on that of Ada. Both Ada and PL/SQL have Pascal as a common ancestor, and so PL/SQL also resembles Pascal in several aspects. However, the structure of a PL/SQL package does not resemble the basic Object Pascal program structure as implemented by a Borland Delphi or Free Pascal unit. Programmers can define public and private global data-types, constants and static variables in a PL/SQL package.[3] PL/SQL also allows for the definition of classes and instantiating these as objects in PL/SQL code. This resembles usage in object-oriented programming languages like Object Pascal, C++ and Java. PL/SQL refers to a class as an "Abstract Data Type" (ADT) or "User Defined Type" (UDT), and defines it as an Oracle SQL data-type as opposed to a PL/SQL user-defined type, allowing its use in both the Oracle SQL Engine and the Oracle PL/SQL engine. The constructor and methods of an Abstract Data Type are written in PL/SQL. The resulting Abstract Data Type can operate as an object class in PL/SQL. Such objects can also persist as column values in Oracle database tables. PL/SQL is fundamentally distinct from Transact-SQL, despite superficial similarities. Porting code from one to the other usually involves non-trivial work, not only due to the differences in the feature sets of the two languages,[4] but also due to the very significant differences in the way Oracle and SQL Server deal with concurrency and locking. There are software tools available that claim to facilitate porting including Oracle Translation Scratch Editor,[5] CEITON MSSQL/Oracle Compiler [6] and SwisSQL.[7] The StepSqlite product is a PL/SQL compiler for the popular small database SQLite. PL/SQL Program Unit A PL/SQL program unit is one of the following: PL/SQL anonymous block, procedure, function, package specification, package body, trigger, type specification, type body, library. Program units are the PL/SQL source code that is compiled, developed and ultimately executed on the database. The basic unit of a PL/SQL source program is the block, which groups together related declarations and statements. A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. These keywords divide the block into a declarative part, an executable part, and an exception-handling part. The declaration section is optional and may be used to define and initialize constants and variables. If a variable is not initialized then it defaults to NULL value. The optional exception-handling part is used to handle run time errors. Only the executable part is required. A block can have a label. Package Packages are groups of conceptually linked functions, procedures, variables, PL/SQL table and record TYPE statements, constants, cursors etc. The use of packages promotes re-use of code. Packages are composed of the package specification and an optional package body. The specification is the interface to the application; it declares the types, variables, constants, exceptions, cursors, and subprograms available. The body fully defines cursors and subprograms, and so implements the specification. Two advantages of packages are: Modular approach, encapsulation/hiding of business logic, security, performance improvement, re-usability. They support object-oriented programming features like function overloading and encapsulation. Using package variables one can declare session level (scoped) variables, since variables declared in the package specification have a session scope.
Views: 3058 radhikaravikumar

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