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• Protecting against transaction concurency (Transaction type; Transaction IsolationLevel)

  - by Vytas999

  Middle-tier component will execute the data access routines in application. The component will call several SQL Server stored procedures to perform database updates. All of these procedure calls run under the control of a single transaction. The code for the middle-tier will implement the following objects: SqlCommand comm = connection.CreateCommand(); SqlTransaction trans; How i must add code to component to specify the highest possible level of protection against such errors(two users try to update the same data concurrently).

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• SQL SERVER – Simple Example of Snapshot Isolation – Reduce the Blocking Transactions

  - by pinaldave

  To learn any technology and move to a more advanced level, it is very important to understand the fundamentals of the subject first. Today, we will be talking about something which has been quite introduced a long time ago but not properly explored when it comes to the isolation level. Snapshot Isolation was introduced in SQL Server in 2005. However, the reality is that there are still many software shops which are using the SQL Server 2000, and therefore cannot be able to maintain the Snapshot Isolation. Many software shops have upgraded to the later version of the SQL Server, but their respective developers have not spend enough time to upgrade themselves with the latest technology. “It works!” is a very common answer of many when they are asked about utilizing the new technology, instead of backward compatibility commands. In one of the recent consultation project, I had same experience when developers have “heard about it” but have no idea about snapshot isolation. They were thinking it is the same as Snapshot Replication – which is plain wrong. This is the same demo I am including here which I have created for them. In Snapshot Isolation, the updated row versions for each transaction are maintained in TempDB. Once a transaction has begun, it ignores all the newer rows inserted or updated in the table. Let us examine this example which shows the simple demonstration. This transaction works on optimistic concurrency model. Since reading a certain transaction does not block writing transaction, it also does not block the reading transaction, which reduced the blocking. First, enable database to work with Snapshot Isolation. Additionally, check the existing values in the table from HumanResources.Shift. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO Now, we will need two different sessions to prove this example. First Session: Set Transaction level isolation to snapshot and begin the transaction. Update the column “ModifiedDate” to today’s date. -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO Please note that we have not yet been committed to the transaction. Now, open the second session and run the following “SELECT” statement. Then, check the values of the table. Please pay attention on setting the Isolation level for the second one as “Snapshot” at the same time when we already start the transaction using BEGIN TRAN. -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values in the table are still original values. They have not been modified yet. Once again, go back to session 1 and begin the transaction. -- Session 1 COMMIT After that, go back to Session 2 and see the values of the table. -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values are yet not changed and they are still the same old values which were there right in the beginning of the session. Now, let us commit the transaction in the session 2. Once committed, run the same SELECT statement once more and see what the result is. -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that it now reflects the new updated value. I hope that this example is clear enough as it would give you good idea how the Snapshot Isolation level works. There is much more to write about an extra level, READ_COMMITTED_SNAPSHOT, which we will be discussing in another post soon. If you wish to use this transaction’s Isolation level in your production database, I would appreciate your comments about their performance on your servers. I have included here the complete script used in this example for your quick reference. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 COMMIT -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Transaction Isolation

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• SQL SERVER – Simple Example of Snapshot Isolation – Reduce the Blocking Transactions

  - by pinaldave

  To learn any technology and move to a more advanced level, it is very important to understand the fundamentals of the subject first. Today, we will be talking about something which has been quite introduced a long time ago but not properly explored when it comes to the isolation level. Snapshot Isolation was introduced in SQL Server in 2005. However, the reality is that there are still many software shops which are using the SQL Server 2000, and therefore cannot be able to maintain the Snapshot Isolation. Many software shops have upgraded to the later version of the SQL Server, but their respective developers have not spend enough time to upgrade themselves with the latest technology. “It works!” is a very common answer of many when they are asked about utilizing the new technology, instead of backward compatibility commands. In one of the recent consultation project, I had same experience when developers have “heard about it” but have no idea about snapshot isolation. They were thinking it is the same as Snapshot Replication – which is plain wrong. This is the same demo I am including here which I have created for them. In Snapshot Isolation, the updated row versions for each transaction are maintained in TempDB. Once a transaction has begun, it ignores all the newer rows inserted or updated in the table. Let us examine this example which shows the simple demonstration. This transaction works on optimistic concurrency model. Since reading a certain transaction does not block writing transaction, it also does not block the reading transaction, which reduced the blocking. First, enable database to work with Snapshot Isolation. Additionally, check the existing values in the table from HumanResources.Shift. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO Now, we will need two different sessions to prove this example. First Session: Set Transaction level isolation to snapshot and begin the transaction. Update the column “ModifiedDate” to today’s date. -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO Please note that we have not yet been committed to the transaction. Now, open the second session and run the following “SELECT” statement. Then, check the values of the table. Please pay attention on setting the Isolation level for the second one as “Snapshot” at the same time when we already start the transaction using BEGIN TRAN. -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values in the table are still original values. They have not been modified yet. Once again, go back to session 1 and begin the transaction. -- Session 1 COMMIT After that, go back to Session 2 and see the values of the table. -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that the values are yet not changed and they are still the same old values which were there right in the beginning of the session. Now, let us commit the transaction in the session 2. Once committed, run the same SELECT statement once more and see what the result is. -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO You will notice that it now reflects the new updated value. I hope that this example is clear enough as it would give you good idea how the Snapshot Isolation level works. There is much more to write about an extra level, READ_COMMITTED_SNAPSHOT, which we will be discussing in another post soon. If you wish to use this transaction’s Isolation level in your production database, I would appreciate your comments about their performance on your servers. I have included here the complete script used in this example for your quick reference. ALTER DATABASE AdventureWorks SET ALLOW_SNAPSHOT_ISOLATION ON GO SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN UPDATE HumanResources.Shift SET ModifiedDate = GETDATE() GO -- Session 2 SET TRANSACTION ISOLATION LEVEL SNAPSHOT BEGIN TRAN SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 1 COMMIT -- Session 2 SELECT ModifiedDate FROM HumanResources.Shift GO -- Session 2 COMMIT SELECT ModifiedDate FROM HumanResources.Shift GO Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Transaction Isolation

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• SQL SERVER – Check the Isolation Level with DBCC useroptions

  - by pinaldave

  In recent consultancy project coordinator asked me – “can you tell me what is the isolation level for this database?” I have worked with different isolation levels but have not ever queried database for the same. I quickly looked up bookonline and found out the DBCC command which can give me the same details. You can run the DBCC UserOptions command on any database to get few details about dateformat, datefirst as well isolation level. DBCC useroptions Set Option                  Value --------------------------- -------------- textsize                    2147483647 language                    us_english dateformat                  mdy datefirst                   7 lock_timeout                -1 quoted_identifier           SET arithabort                  SET ansi_null_dflt_on           SET ansi_warnings               SET ansi_padding                SET ansi_nulls                  SET concat_null_yields_null     SET isolation level             read committed I thought this was very handy script, which I have not used earlier. Thanks Gary for asking right question. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL System Table, SQL Tips and Tricks, T SQL, Technology Tagged: Transaction Isolation

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• SQL SERVER – Transaction Log Full – Transaction Log Larger than Data File – Notes from Fields #001

  - by Pinal Dave

  I am very excited to announce a new series on this blog – Notes from Fields. I have been blogging for almost 7 years on this blog and it has been a wonderful experience. Though, I have extensive experience with SQL and Databases, it is always a good idea that we consult experts for their advice and opinion. Following the same thought process, I have started this new series of Notes from Fields. In this series we will have notes from various experts in the database world. My friends at Linchpin People have graciously decided to support me in my new initiation.  Linchpin People are database coaches and wellness experts for a data driven world. In this very first episode of the Notes from Fields series database expert Tim Radney (partner at Linchpin People) explains a very common issue DBA and Developer faces in their career, when database logs fills up your hard-drive or your database log is larger than your data file. Read the experience of Tim in his own words. As a consultant, I encounter a number of common issues with clients.  One of the more common things I encounter is finding a user database in the FULL recovery model that does not make a regular transaction log backups or ever had a transaction log backup. When I find this, usually the transaction log is several times larger than the data file. Finding this issue is very significant to me in that it allows to me to discuss service level agreements with the client. I get to ask questions such as, are nightly full backups sufficient or do they need point in time recovery.  This conversation has now signed with the customer and gets them to thinking about their disaster recovery and high availability solutions. This issue is also very prominent on SQL Server forums and usually has the title of “Help, my transaction log has filled up my disk” or “Help, my transaction log is many times the size of my database”. In cases where the client only needs the previous full nights backup, I am able to change the recovery model to SIMPLE and shrink the transaction log using DBCC SHRINKFILE (2,1) or by specifying the transaction log file name by using DBCC SHRINKFILE (file_name, target_size). When the client needs point in time recovery then in most cases I will still end up switching the client to the SIMPLE recovery model to truncate the transaction log followed by a full backup. I will then schedule a SQL Agent job to make the regular transaction log backups with an interval determined by the client to meet their service level agreements. It should also be noted that typically when I find an overgrown transaction log the virtual log file count is also out of control. I clean up will always take that into account as well.  That is a subject for a future blog post. If your SQL Server is facing any issue we can Fix Your SQL Server. Additional reading: Monitoring SQL Server Database Transaction Log Space Growth – DBCC SQLPERF(logspace)  SQL SERVER – How to Stop Growing Log File Too Big Shrinking Truncate Log File – Log Full Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• How to nest transactions nicely - "begin transaction" vs "save transaction" and SQL Server

  - by Brian Biales

  Do you write stored procedures that might be used by others?  And those others may or may not have already started a transaction?  And your SP does several things, but if any of them fail, you have to undo them all and return with a code indicating it failed? Well, I have written such code, and it wasn’t working right until I finally figured out how to handle the case when we are already in a transaction, as well as the case where the caller did not start a transaction.  When a problem occurred, my “ROLLBACK TRANSACTION” would roll back not just my nested transaction, but the caller’s transaction as well.  So when I tested the procedure stand-alone, it seemed to work fine, but when others used it, it would cause a problem if it had to rollback.  When something went wrong in my procedure, their entire transaction was rolled back.  This was not appreciated. Now, I knew one could "nest" transactions, but the technical documentation was very confusing.  And I still have not found the approach below documented anywhere.  So here is a very brief description of how I got it to work, I hope you find this helpful. My example is a stored procedure that must figure out on its own if the caller has started a transaction or not.  This can be done in SQL Server by checking the @@TRANCOUNT value.  If no BEGIN TRANSACTION has occurred yet, this will have a value of 0.  Any number greater than zero means that a transaction is in progress.  If there is no current transaction, my SP begins a transaction. But if a transaction is already in progress, my SP uses SAVE TRANSACTION and gives it a name.  SAVE TRANSACTION creates a “save point”.  Note that creating a save point has no effect on @@TRANCOUNT.  So my SP starts with something like this: DECLARE @startingTranCount int SET @startingTranCount = @@TRANCOUNT IF @startingTranCount > 0 SAVE TRANSACTION mySavePointName ELSE BEGIN TRANSACTION -- … Then, when ready to commit the changes, you only need to commit if we started the transaction ourselves: IF @startingTranCount = 0 COMMIT TRANSACTION And finally, to roll back just your changes so far: -- Roll back changes... IF @startingTranCount > 0 ROLLBACK TRANSACTION MySavePointName ELSE ROLLBACK TRANSACTION Here is some code that you can try that will demonstrate how the save points work inside a transaction. This sample code creates a temporary table, then executes selects and updates, documenting what is going on, then deletes the temporary table. if running in SQL Management Studio, set Query Results to: Text for best readability of the results. -- Create a temporary table to test with, we'll drop it at the end. CREATE TABLE #ATable( [Column_A] [varchar](5) NULL ) ON [PRIMARY] GO SET NOCOUNT ON -- Ensure just one row - delete all rows, add one DELETE #ATable -- Insert just one row INSERT INTO #ATable VALUES('000') SELECT 'Before TRANSACTION starts, value in table is: ' AS Note, * FROM #ATable SELECT @@trancount AS CurrentTrancount --insert into a values ('abc') UPDATE #ATable SET Column_A = 'abc' SELECT 'UPDATED without a TRANSACTION, value in table is: ' AS Note, * FROM #ATable BEGIN TRANSACTION SELECT 'BEGIN TRANSACTION, trancount is now ' AS Note, @@TRANCOUNT AS TranCount UPDATE #ATable SET Column_A = '123' SELECT 'Row updated inside TRANSACTION, value in table is: ' AS Note, * FROM #ATable SAVE TRANSACTION MySavepoint SELECT 'Save point MySavepoint created, transaction count now:' as Note, @@TRANCOUNT AS TranCount UPDATE #ATable SET Column_A = '456' SELECT 'Updated after MySavepoint created, value in table is: ' AS Note, * FROM #ATable SAVE TRANSACTION point2 SELECT 'Save point point2 created, transaction count now:' as Note, @@TRANCOUNT AS TranCount UPDATE #ATable SET Column_A = '789' SELECT 'Updated after point2 savepoint created, value in table is: ' AS Note, * FROM #ATable ROLLBACK TRANSACTION point2 SELECT 'Just rolled back savepoint "point2", value in table is: ' AS Note, * FROM #ATable ROLLBACK TRANSACTION MySavepoint SELECT 'Just rolled back savepoint "MySavepoint", value in table is: ' AS Note, * FROM #ATable SELECT 'Both save points were rolled back, transaction count still:' as Note, @@TRANCOUNT AS TranCount ROLLBACK TRANSACTION SELECT 'Just rolled back the entire transaction..., value in table is: ' AS Note, * FROM #ATable DROP TABLE #ATable The output should look like this: Note                                           Column_A ---------------------------------------------- -------- Before TRANSACTION starts, value in table is:  000 CurrentTrancount ---------------- 0 Note                                               Column_A -------------------------------------------------- -------- UPDATED without a TRANSACTION, value in table is:  abc Note                                 TranCount ------------------------------------ ----------- BEGIN TRANSACTION, trancount is now  1 Note                                                Column_A --------------------------------------------------- -------- Row updated inside TRANSACTION, value in table is:  123 Note                                                   TranCount ------------------------------------------------------ ----------- Save point MySavepoint created, transaction count now: 1 Note                                                   Column_A ------------------------------------------------------ -------- Updated after MySavepoint created, value in table is:  456 Note                                              TranCount ------------------------------------------------- ----------- Save point point2 created, transaction count now: 1 Note                                                        Column_A ----------------------------------------------------------- -------- Updated after point2 savepoint created, value in table is:  789 Note                                                     Column_A -------------------------------------------------------- -------- Just rolled back savepoint "point2", value in table is:  456 Note                                                          Column_A ------------------------------------------------------------- -------- Just rolled back savepoint "MySavepoint", value in table is:  123 Note                                                        TranCount ----------------------------------------------------------- ----------- Both save points were rolled back, transaction count still: 1 Note                                                            Column_A --------------------------------------------------------------- -------- Just rolled back the entire transaction..., value in table is:  abc

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• Flush separate Castle ActiveRecord Transaction, and refresh object in another Transaction

  - by eanticev

  I've got all of my ASP.NET requests wrapped in a Session and a Transaction that gets commited only at the very end of the request. At some point during execution of the request, I would like to insert an object and make it visible to other potential threads - i.e. split the insertion into a new transaction, commit that transaction, and move on. The reason is that the request in question hits an API that then chain hits another one of my pages (near-synchronously) to let me know that it processed, and thus double submits a transaction record, because the original request had not yet finished, and thus not committed the transaction record. So I've tried wrapping the insertion code with a new SessionScope, TransactionScope(TransactionMode.New), combination of both, flushing everything manually, etc. However, when I call Refresh on the object I'm still getting the old object state. Here's some code sample for what I'm seeing: Post outsidePost = Post.Find(id); // status of this post is Status.Old using (TransactionScope transaction = new TransactionScope(TransactionMode.New)) { Post p = Post.Find(id); p.Status = Status.New; // new status set here p.Update(); SessionScope.Current.Flush(); transaction.Flush(); transaction.VoteCommit(); } outsidePost.Refresh(); // refresh doesn't get the new status, status is still Status.Old Any suggestions, ideas, and comments are appreciated!

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• ADF Taskflow Transaction Management

  - by raghu.yadav

  There are four transaction management properties available, please refer the guide http://download.oracle.com/docs/cd/E15523_01/web.1111/b31974/taskflows_complex.htm#BABICCGC for detail description. In short : 1) - does not participate in any transaction management 2) Always Use Existing Transaction - the bounded task flow participates in an existing transaction 3) Use Existing Transaction If Possible - bounded task flow either participates in an existing transaction or starts a new transaction 4) Always Begin New Transaction - new transaction starts when the bounded task flow is entered 2) Always Begin New Transaction : There is already a example exists by andre use existing transaction example

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• SQL Server 2014 – delayed transaction durability

  - by Michael Zilberstein

  As I’m downloading SQL Server 2014 CTP2 at this very moment, I’ve noticed new fascinating feature that hadn’t been announced in CTP1 : delayed transaction durability . It means that if your system is heavy on writes and on another hand you can tolerate data loss on some rare occasions – you can consider declaring transaction as DELAYED_DURABILITY = ON . In this case transaction would be committed when log is written to some buffer in memory – not to disk as usual. This way transactions can become...(read more)

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• JPA and MySQL transaction isolation level

  - by armandino

  I have a native query that does a batch insert into a MySQL database: String sql = "insert into t1 (a, b) select x, y from t2 where x = 'foo'"; EntityTransaction tx = entityManager.getTransaction(); try { tx.begin(); int rowCount = entityManager.createNativeQuery(sql).executeUpdate(); tx.commit(); return rowCount; } catch(Exception ex) { tx.rollback(); log.error(...); } This query causes a deadlock: while it reads from t2 with insert .. select, another process tries to insert a row into t2. I don't care about the consistency of reads from t2 when doing an insert .. select and want to set the transaction isolation level to READ_UNCOMMITTED. How do I go about setting it in JPA?

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• Commit in SQL

  - by PRajkumar

  SQL Transaction Control Language Commands (TCL)                                           (COMMIT) Commit Transaction As a SQL language we use transaction control language very frequently. Committing a transaction means making permanent the changes performed by the SQL statements within the transaction. A transaction is a sequence of SQL statements that Oracle Database treats as a single unit. This statement also erases all save points in the transaction and releases transaction locks. Oracle Database issues an implicit COMMIT before and after any data definition language (DDL) statement. Oracle recommends that you explicitly end every transaction in your application programs with a COMMIT or ROLLBACK statement, including the last transaction, before disconnecting from Oracle Database. If you do not explicitly commit the transaction and the program terminates abnormally, then the last uncommitted transaction is automatically rolled back.   Until you commit a transaction: ·         You can see any changes you have made during the transaction by querying the modified tables, but other users cannot see the changes. After you commit the transaction, the changes are visible to other users' statements that execute after the commit ·         You can roll back (undo) any changes made during the transaction with the ROLLBACK statement   Note: Most of the people think that when we type commit data or changes of what you have made has been written to data files, but this is wrong when you type commit it means that you are saying that your job has been completed and respective verification will be done by oracle engine that means it checks whether your transaction achieved consistency when it finds ok it sends a commit message to the user from log buffer but not from data buffer, so after writing data in log buffer it insists data buffer to write data in to data files, this is how it works.   Before a transaction that modifies data is committed, the following has occurred: ·         Oracle has generated undo information. The undo information contains the old data values changed by the SQL statements of the transaction ·         Oracle has generated redo log entries in the redo log buffer of the System Global Area (SGA). The redo log record contains the change to the data block and the change to the rollback block. These changes may go to disk before a transaction is committed ·         The changes have been made to the database buffers of the SGA. These changes may go to disk before a transaction is committed   Note:   The data changes for a committed transaction, stored in the database buffers of the SGA, are not necessarily written immediately to the data files by the database writer (DBWn) background process. This writing takes place when it is most efficient for the database to do so. It can happen before the transaction commits or, alternatively, it can happen some times after the transaction commits.   When a transaction is committed, the following occurs: 1.      The internal transaction table for the associated undo table space records that the transaction has committed, and the corresponding unique system change number (SCN) of the transaction is assigned and recorded in the table 2.      The log writer process (LGWR) writes redo log entries in the SGA's redo log buffers to the redo log file. It also writes the transaction's SCN to the redo log file. This atomic event constitutes the commit of the transaction 3.      Oracle releases locks held on rows and tables 4.      Oracle marks the transaction complete   Note:   The default behavior is for LGWR to write redo to the online redo log files synchronously and for transactions to wait for the redo to go to disk before returning a commit to the user. However, for lower transaction commit latency application developers can specify that redo be written asynchronously and that transaction do not need to wait for the redo to be on disk.   The syntax of Commit Statement is   COMMIT [WORK] [COMMENT ‘your comment’]; ·         WORK is optional. The WORK keyword is supported for compliance with standard SQL. The statements COMMIT and COMMIT WORK are equivalent. Examples Committing an Insert INSERT INTO table_name VALUES (val1, val2); COMMIT WORK; ·         COMMENT Comment is also optional. This clause is supported for backward compatibility. Oracle recommends that you used named transactions instead of commit comments. Specify a comment to be associated with the current transaction. The 'text' is a quoted literal of up to 255 bytes that Oracle Database stores in the data dictionary view DBA_2PC_PENDING along with the transaction ID if a distributed transaction becomes in doubt. This comment can help you diagnose the failure of a distributed transaction. Examples The following statement commits the current transaction and associates a comment with it: COMMIT     COMMENT 'In-doubt transaction Code 36, Call (415) 555-2637'; ·         WRITE Clause Use this clause to specify the priority with which the redo information generated by the commit operation is written to the redo log. This clause can improve performance by reducing latency, thus eliminating the wait for an I/O to the redo log. Use this clause to improve response time in environments with stringent response time requirements where the following conditions apply: The volume of update transactions is large, requiring that the redo log be written to disk frequently. The application can tolerate the loss of an asynchronously committed transaction. The latency contributed by waiting for the redo log write to occur contributes significantly to overall response time. You can specify the WAIT | NOWAIT and IMMEDIATE | BATCH clauses in any order. Examples To commit the same insert operation and instruct the database to buffer the change to the redo log, without initiating disk I/O, use the following COMMIT statement: COMMIT WRITE BATCH; Note: If you omit this clause, then the behavior of the commit operation is controlled by the COMMIT_WRITE initialization parameter, if it has been set. The default value of the parameter is the same as the default for this clause. Therefore, if the parameter has not been set and you omit this clause, then commit records are written to disk before control is returned to the user. WAIT | NOWAIT Use these clauses to specify when control returns to the user. The WAIT parameter ensures that the commit will return only after the corresponding redo is persistent in the online redo log. Whether in BATCH or IMMEDIATE mode, when the client receives a successful return from this COMMIT statement, the transaction has been committed to durable media. A crash occurring after a successful write to the log can prevent the success message from returning to the client. In this case the client cannot tell whether or not the transaction committed. The NOWAIT parameter causes the commit to return to the client whether or not the write to the redo log has completed. This behavior can increase transaction throughput. With the WAIT parameter, if the commit message is received, then you can be sure that no data has been lost. Caution: With NOWAIT, a crash occurring after the commit message is received, but before the redo log record(s) are written, can falsely indicate to a transaction that its changes are persistent. If you omit this clause, then the transaction commits with the WAIT behavior. IMMEDIATE | BATCH Use these clauses to specify when the redo is written to the log. The IMMEDIATE parameter causes the log writer process (LGWR) to write the transaction's redo information to the log. This operation option forces a disk I/O, so it can reduce transaction throughput. The BATCH parameter causes the redo to be buffered to the redo log, along with other concurrently executing transactions. When sufficient redo information is collected, a disk write of the redo log is initiated. This behavior is called "group commit", as redo for multiple transactions is written to the log in a single I/O operation. If you omit this clause, then the transaction commits with the IMMEDIATE behavior. ·         FORCE Clause Use this clause to manually commit an in-doubt distributed transaction or a corrupt transaction. ·         In a distributed database system, the FORCE string [, integer] clause lets you manually commit an in-doubt distributed transaction. The transaction is identified by the 'string' containing its local or global transaction ID. To find the IDs of such transactions, query the data dictionary view DBA_2PC_PENDING. You can use integer to specifically assign the transaction a system change number (SCN). If you omit integer, then the transaction is committed using the current SCN. ·         The FORCE CORRUPT_XID 'string' clause lets you manually commit a single corrupt transaction, where string is the ID of the corrupt transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to specify this clause. ·         Specify FORCE CORRUPT_XID_ALL to manually commit all corrupt transactions. You must have DBA privileges to specify this clause. Examples Forcing an in doubt transaction. Example The following statement manually commits a hypothetical in-doubt distributed transaction. Query the V$CORRUPT_XID_LIST data dictionary view to find the transaction IDs of corrupt transactions. You must have DBA privileges to view the V$CORRUPT_XID_LIST and to issue this statement. COMMIT FORCE '22.57.53';

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• SQL Server transaction log backups,

  - by krimerd

  Hi there, I have a question regarding the transaction log backups in sql server 2008. I am currently taking full backups once a week (Sunday) and transaction log backups daily. I put full backup in folder1 on Sunday and then on Monday I also put the 1st transaction log backup in the same folder. On tuesday, before I take the 2nd transaction log backup I move the first transaction log backup from folder1 an put it into folder2 and then I take the 2nd transaction log backup and put it in the folder1. Same thing on Wed, Thurs and so on. Basicaly in folder1 I always have the latest full backup and the latest transaction log backup while the other transaction log backups are in folder2. My questions is, when sql server is about to take, lets say 4th (Thursday) transaction log backup, does it look for the previous transac log backups (1st, 2nd, and 3rd) so that this new backup will only include the transactions from the last backup or it has some other way of knowing whether there are other transac log backups. Basically, I am asking this because all my transaction log backups seem to be about the same size and I thought that their size will depend on the amount of transactions since the last transaction log backup. Example: If you have a, lets say, full backup and then you take a transac log backup and this transac log backup is lets say 200 MB and now you immediatelly take another transac log backup, this last transac log backup should be considerably smaller than the first one because no or almost no transaction occured between these two backups, right? At least, that's what I've been assuming. What happens in my case is that this second backup is pretty much the same size as the first one and I am wondering if the reason for that is because I moved the first transac log backup to a different folder so now sql server thinks that all I have is just a full backup and it then gets all the transactions that happened since the full backup and puts it in the 2nd transac log backup. Can anyone please explain if my assumptions are right? Thanks...

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• Spring transaction : Transaction not active

  - by Videanu Adrian

  i develop a app using struts2, spring 3.1, Jpa2 and Hibernate. From Spring i use transactions and IoC. so, i have an ajax code block that calls for a struts2 action every second (this is happening for every user that is logged into application (simultaneous users are around 20-30 at a time)). this action name is PopupAction public class PopupAction extends VActionBase implements ServletRequestAware { private static final long serialVersionUID = -293004532677112584L; private iIntermedService intermedService; private HttpServletRequest servletRequest; @Override public String execute() { Integer agentId = (Integer) session.get("USER_AGENT_ID"); Intermed iObj; try { iObj = intermedService.getIntermed(agentId,locationsString); } catch (Exception e) { logger.error("Cannot get Intermed!!! "+e.getMessage()); return ERROR; } return SUCCESS; } } and then i have the service class : @Transactional(readOnly=true) public class IntermedServiceImpl extends GenericIService<Intermed, Integer> implements iIntermedService { @Override public Intermed getIntermed (int agentId,String queueIds) throws Exception { Intermed intermedObj = null; //TODO - find a better implementation for this queueIds parameter!!!! try{ String sql = "SELECT i FROM bla bla bla.....)"; Query q = this.em.createQuery(sql); List<Intermed> iList = q.getResultList(); if (iList.size() == 1){ intermedObj = (Intermed) iList.get(0); //get latest object from DB em.refresh(intermedObj); } }catch(Exception e){ e.printStackTrace(); logger.error(e.getCause()+e.getMessage()); throw e; } return intermedObj; } } here is the spring configuration : <bean id="emfI" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="inboundDS" /> <property name="persistenceUnitName" value="I2PU"/> <!-- GlassFish load-time weaving setup --> <property name="loadTimeWeaver"> <bean class="org.springframework.instrument.classloading.glassfish.GlassFishLoadTimeWeaver"/> </property> </bean> <tx:annotation-driven transaction-manager="txManagerI" /> <tx:advice id="txManagerInboundAdvice" transaction-manager="txManagerI"> <tx:attributes> <tx:method name="*" rollback-for="java.lang.Exception"/> </tx:attributes> </tx:advice> I have names for transactionManager because i have 3 datasources and 3 transaction managers. the problem is that my glassfish logs are full of messages like these: -- removed in order to be able to add more recent logs -- So the cause is : Caused by: java.lang.IllegalStateException: Transaction not active. But i have no idea what can cause this. Any help ? thanks Updates So i have added to @Transactional annotation the transaction manager name that he has to use, but this still does not solved my problem. I have captured a log from the time that the transaction is created until i got that exception: 2012-02-08T15:08:55.954+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (AbstractBeanFactory.java:245) - Returning cached instance of singleton bean 'txManagerVA' 2012-02-08T15:08:55.962+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (AbstractPlatformTransactionManager.java:365) - Creating new transaction with name [xxx.vs.common.services.inbound.IntermedServiceImpl.getIntermed]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT,readOnly; '',-java.lang.Exception 2012-02-08T15:08:55.967+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (JpaTransactionManager.java:368) - Opened new EntityManager [org.hibernate.ejb.EntityManagerImpl@edf83f9] for JPA transaction 2012-02-08T15:08:55.976+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (JpaTransactionManager.java:400) - Exposing JPA transaction as JDBC transaction [org.springframework.orm.jpa.vendor.HibernateJpaDialect$HibernateConnectionHandle@725b979b] 2012-02-08T15:08:55.977+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:193) - Bound value [org.springframework.jdbc.datasource.ConnectionHolder@4fb57177] for key [com.sun.gjc.spi.jdbc40.DataSource40@75fa4851] to thread [thread-pool-1-80(80)] 2012-02-08T15:08:55.978+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:193) - Bound value [org.springframework.orm.jpa.EntityManagerHolder@112c6483] for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@47d4f12f] to thread [thread-pool-1-80(80)] 2012-02-08T15:08:55.979+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:272) - Initializing transaction synchronization 2012-02-08T15:08:55.980+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionAspectSupport.java:362) - Getting transaction for [xxx.vs.common.services.inbound.IntermedServiceImpl.getIntermed] 2012-02-08T15:08:55.983+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (ExtendedEntityManagerCreator.java:423) - Starting resource local transaction on application-managed EntityManager [org.hibernate.ejb.EntityManagerImpl@46d002f4] 2012-02-08T15:08:55.984+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:193) - Bound value [org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerSynchronization@797add43] for key [org.hibernate.ejb.EntityManagerImpl@46d002f4] to thread [thread-pool-1-80(80)] 2012-02-08T15:08:55.986+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (ExtendedEntityManagerCreator.java:400) - Joined local transaction 2012-02-08T15:08:55.991+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionAspectSupport.java:391) - Completing transaction for [xxx.vs.common.services.inbound.IntermedServiceImpl.getIntermed] 2012-02-08T15:08:55.992+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (AbstractPlatformTransactionManager.java:922) - Triggering beforeCommit synchronization 2012-02-08T15:08:55.994+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (AbstractPlatformTransactionManager.java:935) - Triggering beforeCompletion synchronization 2012-02-08T15:08:56.001+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:243) - Removed value [org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerSynchronization@797add43] for key [org.hibernate.ejb.EntityManagerImpl@46d002f4] from thread [thread-pool-1-80(80)] 2012-02-08T15:08:56.002+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (AbstractPlatformTransactionManager.java:752) - Initiating transaction commit 2012-02-08T15:08:56.003+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (JpaTransactionManager.java:507) - Committing JPA transaction on EntityManager [org.hibernate.ejb.EntityManagerImpl@edf83f9] 2012-02-08T15:08:56.008+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (AbstractPlatformTransactionManager.java:948) - Triggering afterCommit synchronization 2012-02-08T15:08:56.010+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (AbstractPlatformTransactionManager.java:964) - Triggering afterCompletion synchronization 2012-02-08T15:08:56.011+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:331) - Clearing transaction synchronization 2012-02-08T15:08:56.012+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:243) - Removed value [org.springframework.orm.jpa.EntityManagerHolder@112c6483] for key [org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean@47d4f12f] from thread [thread-pool-1-80(80)] 2012-02-08T15:08:56.021+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (TransactionSynchronizationManager.java:243) - Removed value [org.springframework.jdbc.datasource.ConnectionHolder@4fb57177] for key [com.sun.gjc.spi.jdbc40.DataSource40@75fa4851] from thread [thread-pool-1-80(80)] 2012-02-08T15:08:56.021+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (JpaTransactionManager.java:593) - Closing JPA EntityManager [org.hibernate.ejb.EntityManagerImpl@edf83f9] after transaction 2012-02-08T15:08:56.022+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|DEBUG [thread-pool-1-80(80)] (EntityManagerFactoryUtils.java:343) - Closing JPA EntityManager 2012-02-08T15:08:56.023+0200|INFO||_ThreadID=184;_ThreadName=Thread-5;|ERROR [thread-pool-1-80(80)] (PopupAction.java:39) - Cannot get Intermed!!! Transaction not active; nested exception is java.lang.IllegalStateException: Transaction not active 2012-02-08T15:08:56.024+0200|SEVERE||_ThreadID=184;_ThreadName=Thread-5;|org.springframework.dao.InvalidDataAccessApiUsageException: Transaction not active; nested exception is java.lang.IllegalStateException: Transaction not active at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:298) at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:106) at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerSynchronization.convertException(ExtendedEntityManagerCreator.java:501) at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerSynchronization.afterCommit(ExtendedEntityManagerCreator.java:481) at org.springframework.transaction.support.TransactionSynchronizationUtils.invokeAfterCommit(TransactionSynchronizationUtils.java:133) at org.springframework.transaction.support.TransactionSynchronizationUtils.triggerAfterCommit(TransactionSynchronizationUtils.java:121) at org.springframework.transaction.support.AbstractPlatformTransactionManager.triggerAfterCommit(AbstractPlatformTransactionManager.java:950) at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:796) at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:723) at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:393) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:120) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at $Proxy325.getIntermed(Unknown Source) at xxx.vs.common.actions.PopupAction.execute(PopupAction.java:37) at sun.reflect.GeneratedMethodAccessor1581.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:453) at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:292) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:255) at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:176) at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211) at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211) at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:90) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:192) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at xxx.vs.common.utils.AuthenticationInterceptor.intercept(AuthenticationInterceptor.java:78) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at com.googlecode.sslplugin.interceptors.SSLInterceptor.intercept(SSLInterceptor.java:128) at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249) at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:510) at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91) at org.apache.catalina 2012-02-08T15:08:56.024+0200|SEVERE||_ThreadID=184;_ThreadName=Thread-5;|.core.StandardHostValve.invoke(StandardHostValve.java:162) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59) at com.sun.grizzly.ContextTask.run(ContextTask.java:71) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513) at java.lang.Thread.run(Thread.java:679) Caused by: java.lang.IllegalStateException: Transaction not active at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:69) at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerSynchronization.afterCommit(ExtendedEntityManagerCreator.java:478) ... 93 more so again..... any ideea ?

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• Geek City: Growing Rows with Snapshot Isolation

  - by Kalen Delaney

  I just finished a wonderful week in Stockholm, teaching a class for Cornerstone Education. We had 19 SQL Server enthusiasts, all eager to find out everything they could about SQL Server Internals. One questions came up on Thursday that I wasn’t sure of the answer to. I jokingly told the student who asked it to consider it a homework exercise, but then I was so interested in the answer, I try to figure it out myself Thursday evening. In this post, I’ll tell you what I did to try to answer the question....(read more)

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• SQL Server transaction log backups,

  - by krimerd

  Hi there, I have a question regarding the transaction log backups in sql server 2008. I am currently taking full backups once a week (Sunday) and transaction log backups daily. I put full backup in folder1 on Sunday and then on Monday I also put the 1st transaction log backup in the same folder. On tuesday, before I take the 2nd transaction log backup I move the first transaction log backup from folder1 an put it into folder2 and then I take the 2nd transaction log backup and put it in the folder1. Same thing on Wed, Thurs and so on. Basicaly in folder1 I always have the latest full backup and the latest transaction log backup while the other transaction log backups are in folder2. My questions is, when sql server is about to take, lets say 4th (Thursday) transaction log backup, does it look for the previous transac log backups (1st, 2nd, and 3rd) so that this new backup will only include the transactions from the last backup or it has some other way of knowing whether there are other transac log backups. Basically, I am asking this because all my transaction log backups seem to be about the same size and I thought that their size will depend on the amount of transactions since the last transaction log backup. Can anyone please explain if my assumptions are right? Thanks...

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• Stairway to Transaction Log Management in SQL Server, Level 1: Transaction Log Overview

  The transaction log is used by SQL Server to maintain data consistency and integrity. If the database is not in Simple-recovery mode, it can also be used in an appropriate backup regime to restore the database to a point in time. The Future of SQL Server Monitoring "Being web-based, SQL Monitor enables you to check on your servers from almost any location" Jonathan Allen.Try SQL Monitor now.

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• Understanding EDI 997

  - by VishnuTiwariBlog

  Hi Guys, This is for the EDI starter. Below is the complete detail of EDI 997 segment and element details. 997 Functional Acknowledgment Transaction Layout:   No. Seg ID Name Description Example M/O 010 ST Transaction Set Header To indicate the start of a transaction set and to assign a control number ST*997*382823~   M ST01   Code uniquely identifying a Transaction Set   M ST02   Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set   M 020 AK1 Functional Group Response Header To start acknowledgment of a functional group AK1*QM*2459823 M        AK101   Code identifying a group of application related transaction sets IN Invoice Information (810) SH Ship Notice/Manifest (856)     AK102   Assigned number originated and maintained by the sender     030 AK2 Transaction Set Response Header To start acknowledgment of a single transaction set AK2*856*001 M AK201   Code uniquely identifying a Transaction Set 810 Invoice 856 Ship Notice/Manifest   M AK202   Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set   M 040 AK3 Data Segment Note To report errors in a data segment and identify the location of the data segment AK3*TD3*9 O AK301 Segment ID Code Code defining the segment ID of the data segment in error (See Appendix A - Number 77)     AK302 Segment Position in Transaction Set The numerical count position of this data segment from the start of the transaction set: the transaction set header is count position 1     050 AK4 Data Element Note To report errors in a data element or composite data structure and identify the location of the data element AK4*2**2 O AK401 Position in Segment Code indicating the relative position of a simple data element, or the relative position of a composite data structure combined with the relative position of the component data element within the composite data structure, in error; the count starts with 1 for the simple data element or composite data structure immediately following the segment ID     AK402 Element Position in Segment This is used to indicate the relative position of a simple data element, or the relative position of a composite data structure with the relative position of the component within the composite data structure, in error; in the data segment the count starts with 1 for the simple data element or composite data structure immediately following the segment ID     AK403 Data Element Syntax Error Code Code indicating the error found after syntax edits of a data element 1 Mandatory Data Element Missing 2 Conditional Required Data Element Missing 3 Too Many Data Elements 4 Data Element Too Short 5 Data Element Too Long 6 Invalid Character in Data Element 7 Invalid Code Value 8 Invalid Date 9 Invalid Time 10 Exclusion Condition Violated     AK404 Copy of Bad Data Element This is a copy of the data element in error     060 AK5 AK5 Transaction Set Response Trailer To acknowledge acceptance or rejection and report errors in a transaction set AK5*A~ AK5*R*5~ M AK501 Transaction Set Acknowledgment Code Code indicating accept or reject condition based on the syntax editing of the transaction set A Accepted E Accepted But Errors Were Noted R Rejected     AK502 Transaction Set Syntax Error Code Code indicating error found based on the syntax editing of a transaction set 1 Transaction Set Not Supported 2 Transaction Set Trailer Missing 3 Transaction Set Control Number in Header and Trailer Do Not Match 4 Number of Included Segments Does Not Match Actual Count 5 One or More Segments in Error 6 Missing or Invalid Transaction Set Identifier 7 Missing or Invalid Transaction Set Control Number     070 AK9 Functional Group Response Trailer To acknowledge acceptance or rejection of a functional group and report the number of included transaction sets from the original trailer, the accepted sets, and the received sets in this functional group AK9*A*1*1*1~ AK9*R*1*1*0~ M AK901 Functional Group Acknowledge Code Code indicating accept or reject condition based on the syntax editing of the functional group A Accepted E Accepted, But Errors Were Noted. R Rejected     AK902 Number of Transaction Sets Included Total number of transaction sets included in the functional group or interchange (transmission) group terminated by the trailer containing this data element     AK903 Number of Received Transaction Sets Number of Transaction Sets received     AK904 Number of Accepted Transaction Sets Number of accepted Transaction Sets in a Functional Group     AK905 Functional Group Syntax Error Code Code indicating error found based on the syntax editing of the functional group header and/or trailer 1 Functional Group Not Supported 2 Functional Group Version Not Supported 3 Functional Group Trailer Missing 4 Group Control Number in the Functional Group Header and Trailer Do Not Agree 5 Number of Included Transaction Sets Does Not Match Actual Count 6 Group Control Number Violates Syntax     080 SE Transaction Set Trailer To indicate the end of the transaction set and provide the count of the transmitted segments (including the beginning (ST) and ending (SE) segments) SE*9*223~ M SE01 Number of Included Segments Total number of segments included in a transaction set including ST and SE segments     SE02 Transaction Set Control Number Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set

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• Understanding EDI 997.

  - by VishnuTiwariBlog

  Hi Guys, This is for the EDI starter. Below is the complete detail of EDI 997 segment and element details. 997 Functional Acknowledgment Transaction Layout: No. Seg ID Name Description Example M/O 010 ST Transaction Set Header To indicate the start of a transaction set and to assign a control number ST*997*382823~   M ST01   Code uniquely identifying a Transaction Set   M ST02   Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set   M 020 AK1 Functional Group Response Header To start acknowledgment of a functional group AK1*QM*2459823 M        AK101   Code identifying a group of application related transaction sets IN Invoice Information (810) SH Ship Notice/Manifest (856)     AK102   Assigned number originated and maintained by the sender     030 AK2 Transaction Set Response Header To start acknowledgment of a single transaction set AK2*856*001 M AK201   Code uniquely identifying a Transaction Set 810 Invoice 856 Ship Notice/Manifest   M AK202   Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set   M 040 AK3 Data Segment Note To report errors in a data segment and identify the location of the data segment AK3*TD3*9 O AK301 Segment ID Code Code defining the segment ID of the data segment in error (See Appendix A - Number 77)     AK302 Segment Position in Transaction Set The numerical count position of this data segment from the start of the transaction set: the transaction set header is count position 1     050 AK4 Data Element Note To report errors in a data element or composite data structure and identify the location of the data element AK4*2**2 O AK401 Position in Segment Code indicating the relative position of a simple data element, or the relative position of a composite data structure combined with the relative position of the component data element within the composite data structure, in error; the count starts with 1 for the simple data element or composite data structure immediately following the segment ID     AK402 Element Position in Segment This is used to indicate the relative position of a simple data element, or the relative position of a composite data structure with the relative position of the component within the composite data structure, in error; in the data segment the count starts with 1 for the simple data element or composite data structure immediately following the segment ID     AK403 Data Element Syntax Error Code Code indicating the error found after syntax edits of a data element 1 Mandatory Data Element Missing 2 Conditional Required Data Element Missing 3 Too Many Data Elements 4 Data Element Too Short 5 Data Element Too Long 6 Invalid Character in Data Element 7 Invalid Code Value 8 Invalid Date 9 Invalid Time 10 Exclusion Condition Violated     AK404 Copy of Bad Data Element This is a copy of the data element in error     060 AK5 AK5 Transaction Set Response Trailer To acknowledge acceptance or rejection and report errors in a transaction set AK5*A~ AK5*R*5~ M AK501 Transaction Set Acknowledgment Code Code indicating accept or reject condition based on the syntax editing of the transaction set A Accepted E Accepted But Errors Were Noted R Rejected     AK502 Transaction Set Syntax Error Code Code indicating error found based on the syntax editing of a transaction set 1 Transaction Set Not Supported 2 Transaction Set Trailer Missing 3 Transaction Set Control Number in Header and Trailer Do Not Match 4 Number of Included Segments Does Not Match Actual Count 5 One or More Segments in Error 6 Missing or Invalid Transaction Set Identifier 7 Missing or Invalid Transaction Set Control Number     070 AK9 Functional Group Response Trailer To acknowledge acceptance or rejection of a functional group and report the number of included transaction sets from the original trailer, the accepted sets, and the received sets in this functional group AK9*A*1*1*1~ AK9*R*1*1*0~ M AK901 Functional Group Acknowledge Code Code indicating accept or reject condition based on the syntax editing of the functional group A Accepted E Accepted, But Errors Were Noted. R Rejected     AK902 Number of Transaction Sets Included Total number of transaction sets included in the functional group or interchange (transmission) group terminated by the trailer containing this data element     AK903 Number of Received Transaction Sets Number of Transaction Sets received     AK904 Number of Accepted Transaction Sets Number of accepted Transaction Sets in a Functional Group     AK905 Functional Group Syntax Error Code Code indicating error found based on the syntax editing of the functional group header and/or trailer 1 Functional Group Not Supported 2 Functional Group Version Not Supported 3 Functional Group Trailer Missing 4 Group Control Number in the Functional Group Header and Trailer Do Not Agree 5 Number of Included Transaction Sets Does Not Match Actual Count 6 Group Control Number Violates Syntax     080 SE Transaction Set Trailer To indicate the end of the transaction set and provide the count of the transmitted segments (including the beginning (ST) and ending (SE) segments) SE*9*223~ M SE01 Number of Included Segments Total number of segments included in a transaction set including ST and SE segments     SE02 Transaction Set Control Number Identifying control number that must be unique within the transaction set functional group assigned by the originator for a transaction set

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• SQL SERVER – Concurrancy Problems and their Relationship with Isolation Level

  - by pinaldave

  Concurrency is simply put capability of the machine to support two or more transactions working with the same data at the same time. This usually comes up with data is being modified, as during the retrieval of the data this is not the issue. Most of the concurrency problems can be avoided by SQL Locks. There are four types of concurrency problems visible in the normal programming. 1)      Lost Update – This problem occurs when there are two transactions involved and both are unaware of each other. The transaction which occurs later overwrites the transactions created by the earlier update. 2)      Dirty Reads – This problem occurs when a transactions selects data that isn’t committed by another transaction leading to read the data which may not exists when transactions are over. Example: Transaction 1 changes the row. Transaction 2 changes the row. Transaction 1 rolls back the changes. Transaction 2 has selected the row which does not exist. 3)      Nonrepeatable Reads – This problem occurs when two SELECT statements of the same data results in different values because another transactions has updated the data between the two SELECT statements. Example: Transaction 1 selects a row, which is later on updated by Transaction 2. When Transaction A later on selects the row it gets different value. 4)      Phantom Reads – This problem occurs when UPDATE/DELETE is happening on one set of data and INSERT/UPDATE is happening on the same set of data leading inconsistent data in earlier transaction when both the transactions are over. Example: Transaction 1 is deleting 10 rows which are marked as deleting rows, during the same time Transaction 2 inserts row marked as deleted. When Transaction 1 is done deleting rows, there will be still rows marked to be deleted. When two or more transactions are updating the data, concurrency is the biggest issue. I commonly see people toying around with isolation level or locking hints (e.g. NOLOCK) etc, which can very well compromise your data integrity leading to much larger issue in future. Here is the quick mapping of the isolation level with concurrency problems: Isolation Dirty Reads Lost Update Nonrepeatable Reads Phantom Reads Read Uncommitted Yes Yes Yes Yes Read Committed No Yes Yes Yes Repeatable Read No No No Yes Snapshot No No No No Serializable No No No No I hope this 400 word small article gives some quick understanding on concurrency issues and their relation to isolation level. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Repair a SQL Server Database Using a Transaction Log Explorer

  - by Pinal Dave

  In this blog, I’ll show how to use ApexSQL Log, a SQL Server transaction log viewer. You can download it for free, install, and play along. But first, let’s describe some disaster recovery scenarios where it’s useful. About SQL Server disaster recovery Along with database development and administration, you must work on a good recovery plan. Disasters do happen and no one’s immune. What you can do is take all actions needed to be ready for a disaster and go through it with minimal data loss and downtime. Besides creating a recovery plan, it’s necessary to have a list of steps that will be executed when a disaster occurs and to test them before a disaster. This way, you’ll know that the plan is good and viable. Testing can also be used as training for all team members, so they can all understand and execute it when the time comes. It will show how much time is needed to have your servers fully functional again and how much data you can lose in a real-life situation. If these don’t meet recovery-time and recovery-point objectives, the plan needs to be improved. Keep in mind that all major changes in environment configuration, business strategy, and recovery objectives require a new recovery plan testing, as these changes most probably induce a recovery plan changing and tweaking. What is a good SQL Server disaster recovery plan? A good SQL Server disaster recovery strategy starts with planning SQL Server database backups. An efficient strategy is to create a full database backup periodically. Between two successive full database backups, you can create differential database backups. It is essential is to create transaction log backups regularly between full database backups. Keep in mind that transaction log backups can be created only on databases in the full recovery model. In other words, a simple, but efficient backup strategy would be a full database backup every night, a transaction log backup every hour, or every 15 minutes. The frequency depends on how much data you can afford to lose and how busy the database is. Another option, instead of creating a full database backup every night, is to create a full database backup once a week (e.g. on Friday at midnight) and differential database backup every night until next Friday when you will create a full database backup again. Once you create your SQL Server database backup strategy, schedule the backups. You can do that easily using SQL Server maintenance plans. Why are transaction logs important? Transaction log backups contain transactions executed on a SQL Server database. They provide enough information to undo and redo the transactions and roll back or forward the database to a point in time. In SQL Server disaster recovery situations, transaction logs enable to repair a SQL Server database and bring it to the state before the disaster. Be aware that even with regular backups, there will be some data missing. These are the transactions made between the last transaction log backup and the time of the disaster. In some situations, to repair your SQL Server database it’s not necessary to re-create the database from its last backup. The database might still be online and all you need to do is roll back several transactions, such as wrong update, insert, or delete. The restore to a point in time feature is available in SQL Server, but for large databases, it is very time-consuming, as SQL Server first restores a full database backup, and then restores transaction log backups, one after another, up to the recovery point. During that time, the database is unavailable. This is where a SQL Server transaction log viewer can help. For optimal recovery, besides having a database in the full recovery model, it’s important that you haven’t manually truncated the online transaction log. This ensures that all transactions made after the last transaction log backup are still in the online transaction log. All you have to do is read and replay them. How to read a SQL Server transaction log? SQL Server doesn’t provide an option to read transaction logs. There are several SQL Server commands and functions that read the content of a transaction log file (fn_dblog, fn_dump_dblog, and DBCC PAGE), but they are undocumented. They require T-SQL knowledge, return a large number of not easy to read and understand columns, sometimes in binary or hexadecimal format. Another challenge is reading UPDATE statements, as it’s necessary to match it to a value in the MDF file. When you finally read the transactions executed, you have to create a script for it. How to easily repair a SQL database? The easiest solution is to use a transaction log reader that will not only read the transactions in the transaction log files, but also automatically create scripts for the read transactions. In the following example, I will show how to use ApexSQL Log to repair a SQL database after a crash. If a database has crashed and both MDF and LDF files are lost, you have to rely on the full database backup and all subsequent transaction log backups. In another scenario, the MDF file is lost, but the LDF file is available. First, restore the last full database backup on SQL Server using SQL Server Management Studio. I’ll name it Restored_AW2014. Then, start ApexSQL Log It will automatically detect all local servers. If not, click the icon right to the Server drop-down list, or just type in the SQL Server instance name. Select the Windows or SQL Server authentication type and select the Restored_AW2014 database from the database drop-down list. When all options are set, click Next. ApexSQL Log will show the online transaction log file. Now, click Add and add all transaction log backups created after the full database backup I used to restore the database. In case you don’t have transaction log backups, but the LDF file hasn’t been lost during the SQL Server disaster, add it using Add.   To repair a SQL database to a point in time, ApexSQL Log needs to read and replay all the transactions in the transaction log backups (or the LDF file saved after the disaster). That’s why I selected the Whole transaction log option in the Filter setup. ApexSQL Log offers a range of various filters, which are useful when you need to read just specific transactions. You can filter transactions by the time of the transactions, operation type (e.g. to read only data inserts), table name, SQL Server login that made the transaction, etc. In this scenario, to repair a SQL database, I’ll check all filters and make sure that all transactions are included. In the Operations tab, select all schema operations (DDL). If you omit these, only the data changes will be read so if there were any schema changes, such as a new function created, or an existing table modified, they will be ignored and database will not be properly repaired. The data repair for modified tables will fail. In the Tables tab, I’ll make sure all tables are selected. I will uncheck the Show operations on dropped tables option, to reduce the number of transactions. Click Next. ApexSQL Log offers three options. Select Open results in grid, to get a user-friendly presentation of the transactions. As you can see, details are shown for every transaction, including the old and new values for updated columns, which are clearly highlighted. Now, select them all and then create a redo script by clicking the Create redo script icon in the menu.   For a large number of transactions and in a critical situation, when acting fast is a must, I recommend using the Export results to file option. It will save some time, as the transactions will be directly scripted into a redo file, without showing them in the grid first. Select Generate reconstruction (REDO) script , change the output path if you want, and click Finish. After the redo T-SQL script is created, ApexSQL Log shows the redo script summary: The third option will create a command line statement for a batch file that you can use to schedule execution, which is not really applicable when you repair a SQL database, but quite useful in daily auditing scenarios. To repair your SQL database, all you have to do is execute the generated redo script using an integrated developer environment tool such as SQL Server Management Studio or any other, against the restored database. You can find more information about how to read SQL Server transaction logs and repair a SQL database on ApexSQL Solution center. There are solutions for various situations when data needs to be recovered, restored, or transactions rolled back. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Java Transaction Service without the application server

  - by johnny

  Is it possible to have a Java standalone application (no application server attached) that exposes some operations that a client can call and be the one to manage the transactions? I was thinking this application to expose JNDI resources and get a hold of a java:comp/UserTransaction from there, get also a bean from there and call methods A, B and C on it and coordinate the transaction from the client? The application I'm writing isn't complex enough so that I need a big application server around it so I'm thinking to have a standalone JTS inside it that the client could interact with from a transactions point of view. I don't have much experience with distributed transactions and don't really know how to tackle the issue. Is it even possible? Am I getting myself into something beyond what a mere mortal (programmer) can handle? How can I approach this?

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• Book review: SQL Server Transaction Log Management

  - by Hugo Kornelis

  It was an offer I could not resist. I was promised a free copy of one of the newest books from Red Gate Books , SQL Server Transaction Log Management (by Tony Davis and Gail Shaw ), with the caveat that I should write a review after reading it. Mind you, not a commercial, “make sure we sell more copies” kind of review, but a review of my actual thoughts. Yes, I got explicit permission to be my usual brutally honest self. A total win/win for me! First, I get a free book – and free is always good,...(read more)

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• Spring can commit Transaction in finally block with RunTimeException in try block [migrated]

  - by Chance Lai

  The project used Spring + Hibernate Sample code: public void method(){ try{ dao.saveA(entityA); throw RuntimeException; dao.saveB(entityB); }catch(RuntimeException e){ throw e; }finally{ dao.saveC(entityC) } } Finally, just entityC will be saved in database in test. I think saveA, saveB, saveC in the same transaction,they should not be committed. In this case, I want to know why entityC is committed. How does Spring do this in the finally block?

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• Transaction Isolation Level of Serializable not working for me

  - by Shahriar

  I have a website which is used by all branches of a store and what it does is that it records customer purchases into a table called myTransactions.myTransactions table has a column named SerialNumber.For each purchase i create a record in the transactions table and assign a serial to it.The stored procedure that does this calls a UDF function to get a new serialNumber before inserting the record.Like below : Create Procedure mytransaction_Insert as begin insert into myTransactions(column1,column2,column3,...SerialNumber) values( Value1 ,Value2,Value3,...., getTransactionNSerialNumber()) end Create function getTransactionNSerialNumber as begin RETURN isnull(SELECT TOP (1) SerialNumber FROM myTransactions READUNCOMMITTED ORDER BY SerialNumber DESC),0) + 1 end The website is being used by so many users in different stores at the same time and it is creating many duplicate serialNumbers(same SerialNumbers).So i added a Sql transaction with ReadCommitted level to the transaction and i still got duplicate transaction numbers.I changed it to SERIALIZABLE in order to lock the resources and i not only got duplicate transaction numbers(!!HOW!!) but i also got sporadic deadlocks between the same stored procedure calls.This is what i tried : (With ommissions of try catch blocks and rollbacks) Create Procedure mytransaction_Insert as begin SET TRANSACTION ISOLATION LEVEL SERIALIZABLE BEGIN TRASNACTION ins insert into myTransactions(column1,column2,column3,...SerialNumber) values( Value1 ,Value2 , Value3, ...., getTransactionNSerialNumber()) COMMIT TRANSACTION ins SET TRANSACTION ISOLATION READCOMMITTED end I even copied the function that gets the serial number directly into the stored procedure instead of the UDF function call and still got duplicate serialNumbers.So,How can a stored procedure line create something Like the c# lock() {} block. By the way,i have to implement the transaction serial number using the same pattern and i can't change the serialNumber to any other identity field or whatever.And for some reasons i need to generate the serialNumber inside the databse and i can't move SerialNumber generation to application level. Thank you.

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• google analytics reverse transaction not working with sales performance

  - by prasad maganti

  We have google analytics account and trying to do reverse transaction. We have created a transaction on one date and reverse transaction on some other date. After transaction if we do reverse transaction it disappears from transactions list. Is it the expected behavior or abnormal behavior? But, if we check the same order data in sales performance, the reverse transaction does not reflects on when we created the transaction, it reflecting on when we made reverse transaction date. It should not be do like this. The reverse transaction should affect the same date on when we made transaction date.

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