Tagged Questions

A mechanism for committing a consistent set of changes into a database atomically.

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14
votes
7answers
4k views

Oracle - Any way to view uncommited changes to a particular table?

I'm debugging through a batch proess currently that does a lot of DML statements, but doesn't do a commit right away. It would be nice to be able to view the "pending" changes while the transaction ...
12
votes
3answers
8k views

What risks are there if we enable read committed snapshot in sql-server?

I have read here that some extra data will be stored per row so we might see a performance degradation but what other risks are there? eg. Will this affect recovery of the database? Is there anything ...
11
votes
4answers
2k views

Is ROLLBACK a fast operation?

Is it true that RDBMS systems are optimized for COMMIT operations? How much slower/faster are ROLLBACK operations and why?
10
votes
3answers
10k views

How to find out who deleted some data SQL Server

My boss had a query from a customer yesterday asking how they could find out who deleted some data in their SQL Server database (it is the express edition if that matters). I thought this could be ...
9
votes
1answer
682 views

SQL query for combinations without repetition

I need a query which can be used in (or as) a function and retrieves all combinations of n values. And I need all combinations of length k where k = 1..n. Extended sample input and result so input ...
9
votes
1answer
278 views

Disable explicit commits in JDBC, detect them in SQL, or put the database in a readonly state

Background: I'm working on http://sqlfiddle.com (my site), and am trying to prevent one avenue of abuse possible there. I'm hoping that by asking about a problem I'm currently addressing, I don't ...
7
votes
2answers
523 views

Is it a bad practice to always create a transaction?

Is it a bad practice to always create a transaction? For example, it is a good practice to create a transaction for nothing but one simple SELECT? What is the cost of creating a transaction when it ...
7
votes
1answer
809 views

Generating Invoices and Tracking

Every 2 weeks, the system will generate the invoices for the companies. Company will receive an invoice on the 1st and 16th every month. (It will run via Cron Job every 2 week. It scan through the ...
7
votes
1answer
1k views

What is the “Chaos” Isolation level and when should it be used?

ADO.NET documentation shows the possibility of setting the transaction level for a SQL transaction to Chaos. It sounds unpleasant, but if the feature is there, presumably it has some legitimate use. ...
6
votes
6answers
2k views

On DB2, who updated a record and what did the record look like before the update?

(SQL Server 2008 R2 Standard, database under full recovery) I have a table with fields id, firstname, lastname. A statement is executed: insert into dbo.sometable (id, firstname, lastname) values ...
6
votes
2answers
183 views

Can I use transaction logs to rebuild a database?

We've had some data loss and don't have a reliable backup it seems. We do have HUGE transaction logs and there was some thought that we might be able to use these to get back to a certain point. Is ...
5
votes
3answers
2k views

Will the transaction log shrink automagically in SQL Server?

When SQL Server database in a SIMPLE mode, you don't have to care about the transaction log bakcups. But in a SIMPLE mode, the transaction log seems to grow as it does in FULL mode. Does is truncate ...
5
votes
3answers
1k views

SQL Server - what isolation level for non-blocking select statements?

I have a long running transaction (called, say, T1) that performs some deletes, updates and inserts on a table in SQL Server 2008 R2. At the same time, another process periodically runs select ...
5
votes
1answer
149 views

Does the transaction isolation level affect indices as well?

Here's one for the SQL Server gurus: if I set my SQL Server 2008 transaction isolation level to READ UNCOMMITTED, does that also affect the index pages? E.g. using ISOLATION LEVEL READ UNCOMMITTED, ...
5
votes
3answers
571 views

Deadlock Error from SQL Server 2000 to SQL Server 2008

After migrating data from SQL Server 2000 to SQL Server 2008,when I am doing any a transaction in the table which find out more row on the database,that's gives me error. Transaction (Process ID ...
5
votes
1answer
162 views

Triggers and the Transaction

We recently made a change to create constraints based on logic previously used in stored procedures, and part of that included the use of INSTEAD OF triggers to centralize logic. The logic is ...
4
votes
2answers
521 views

Oracle 11g see transaction or session start time

I want to know when a session or transaction started. The deadlock file doesn't give me this information. Is there some logfile that keeps these records? I've got a transaction id "TX-1234-abcd", a ...
4
votes
1answer
1k views

How to use transactions with SQL Server DDL?

I have a login table into which all inserts are done by a single stored procedure. CREATE TABLE dbo.LogTable( LogRefnr int IDENTITY(1, 1) NOT NULL, LogQuery varchar(255) NOT NULL, LogTime ...
4
votes
2answers
232 views

How do I query only for committed data while avoid a deadlock

I have a system writing batches of queries as transactions (to maintain coherency), these can be sets of 30-100 queries per transaction. These are done on multiple tables At the same time there are ...
4
votes
2answers
140 views

Transactions, references and how to enforce double entry bookkeeping? (PG)

Double entry bookkeeping is a set of rules for recording financial information in a financial accounting system in which every transaction or event changes at least two different nominal ...
4
votes
3answers
259 views

Can I change table structure in a transaction and then roll it back if there is an error?

I have some ALTER TABLE statements that I am running. Not all of them work (they are the result of running SQL Data Compare) and I want to group them in some transactions and roll back the statements ...
4
votes
3answers
119 views

Get transactions that failed or were never committed

Is there anywhere I can look to find failed transactions in SQL server 2012?
4
votes
2answers
985 views

Concurrent Transactions vs Simultaneous Transactions

Chapter 6 of David Kroenke's Database Concepts: Database Administration Is my understanding correct that in a database, simultaneous transactions don't really happen. Instead, it is a concurrent ...
4
votes
1answer
725 views

How to UPDATE just one record in DB2?

In DB2, I need to do a SELECT FROM UPDATE, to put an update + select in a single transaction. But I need to make sure to update only one record per transaction. Familiar with the LIMIT clause from ...
4
votes
1answer
2k views

Current isolation level in oracle

How to get the current (default) transaction isolation level in oracle?
4
votes
2answers
166 views

Delete all rows within transaction: what would happen to other transactions?

I currently have a function in PostgreSQL that creates a temp table, fills it, performs some tricky selects and returns results. postgresql's temp tables are local to functions, so this helps me avoid ...
3
votes
2answers
4k views

SQL Server Transaction Timeout

Is there a way in SQL Server 2008 R2 to cause a timeout for a database modification involving a transaction? We have a scenario where our application code hangs or throws an exception and fails to ...
3
votes
2answers
1k views

Will a delete then insert within a transaction cascade?

I had a question about what the expected and actual behaviour for the following scenario is. The scenario is one where a database table ([table1]) is cleared and reloaded every day. The table has an ...
3
votes
1answer
251 views

Trigger in combination with transaction

Suppose we have the following situation: We have a table (let's say Table_A), wich has a trigger on INSERT. The trigger job is to update some rows in table_B based on the inserted values in table_A. ...
3
votes
3answers
326 views

Why am i getting deadlocks with 1 read and 1 write thread in SQL

if anyone could please help me understand why the following transactions deadlock? I am providing the 2 transactions and the indexes for each table: Transaction 1: SELECT blockId, blockData, ...
3
votes
3answers
149 views

sleeping SPID blocking other transactions

I'm really having trouble tracking down some blocking we are experiencing. The root blocking SPID's status is 'sleeping', the cmd is 'AWAITING COMMAND', and the sqltext is 'SET TRANSACTION ISOLATION ...
3
votes
1answer
196 views

Does blocking always mean open transaction?

This may seem a bit dull question but does blocking always mean that there is open transaction and that may cause transaction log grow to infinity because open transaction prevents log truncation ...
3
votes
1answer
281 views

Find out if two rows came from same transaction in Oracle

I am using Oracle 11.1 and would like to figure out if two rows in one table where inserted by the same transaction. Is there an easy sql statement to map a row to an transactions id? The table is an ...
3
votes
1answer
2k views

MySQL transaction size - how big is too big?

I have an import process that runs every so often and I want it to be an 'all or nothing' kind of deal, aka: a transaction. There are many aspects, and the imports may yield anywhere between ...
3
votes
1answer
183 views

Is SQL Server Replication transactionally 'safe' across all published tables?

We have a system that has one of its datasources still on SQL Server 2000. In order to achieve higher availability, we are looking to setup transactional replication from this 2000 server to a 2008 ...
3
votes
1answer
116 views

SQL Server 2008 - Adding a column and a filtered index within a single transaction?

This is more of a general question. Why can you not add a filtered index within the same transaction scope as adding the new column in the first place? The solution is of course simple, just make two ...
3
votes
1answer
462 views

Deleting MySQL table with pending transactions

Is there a way to delete an InnoDB table or database with pending transactions in MySQL (preferably on file system level)? What happened: I use MySQL 5.5.28 and ran LOAD DATA INFILE… to import a ...
3
votes
2answers
423 views

How do I implement insert-if-not-found for transactions at serializable isolation level?

I'm having a hard time figuring out how to exactly implement a 'insert if not found' function. Consider the following. We have a table called artist with 2 columns, (name, id) where name is the ...
3
votes
1answer
138 views

SQL Server : KEY lock prevents FK on nearby row, but not SELECT [closed]

I have the following table structure (simplified, pseudocode): TABLE dbo.Users (Id int NOT NULL IDENTITY PRIMARY KEY) TABLE dbo.Transfers ( Id int NOT NULL IDENTITY PRIMARY KEY, ...
3
votes
1answer
852 views

Why is this rollback needed when using sp_addextendedproperty in a stored procedure?

In enter link description here I showed, how I document databases. To insert the extended properties, initially I uses plan sequences of sp_addextendedproperty calls. But lately I wanted to catch ...
3
votes
2answers
437 views

Transaction and Try-catch in SQL Server Job

We have DML operations in each step of a SQL Server job. To ensure the update/insert will be rolled back in case something goes wrong, I have wrapped the data modifications of each step in TRY CATCH ...
3
votes
1answer
593 views

Duplicate UNIQUE KEY error after ROLLBACK in MySQL

I have a table like this mysql> describe seudonimos; +--------------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra ...
2
votes
2answers
68 views

Partial rollback doesn't decrement trancount

Suppose I have an open SQL Server session, and do the following: begin tran insert into People (Id) values (1) select @@TRANCOUNT -- Prints 1 save transaction tt begin tran select @@TRANCOUNT ...
2
votes
2answers
2k views

Using MySQL triggers or transactions?

I want to ask your opinion in using MySQL triggers or transactions in a website. Actually I have a history payment table with - UserId | OperationId | Comment | Credits | Sign (debit or credit). So ...
2
votes
1answer
313 views

Rollback generate scripts

During the development of applications users often want to add new modules, business rules etc. So I've often used SQL Server 2008 option to create scripts from the development DB to generate new ...
2
votes
1answer
316 views

Transaction and data consistency during a failure

When a database begins a transaction, all statements executed in that transaction are isolated and atomic (and consistent and durable). These are pretty much the definition of a transaction. ...
2
votes
1answer
98 views

Transaction level difference between using a large IN filter VS. “BEGIN TRAN/COMMIT”

I would like to delete about 100,000 records with minimal server overhead. I've had a few nagging questions I haven't been able to test properly so I figured I'd ask some experts here. Which would ...
2
votes
2answers
1k views

What server property makes TransactionScope escalating to MSDTC?

In our application we're using TransactionScope's. We're aiming to not use the MSDTC service because it's a lot slower than lightweight transactions. using (var transactionScope = new ...
2
votes
2answers
83 views

How to rollback the identity seed after deadlock

Now that's an approximate sequence of operations Im performing: SET IDENTITY_INSERT <table-name> ON; INSERT SOMETHING to <table-name> with explicitly specifyed id DECLARE @oldID bigint ...
2
votes
1answer
307 views

In InnoDB, does a Transaction imply any implicit locking of a table?

The Isolation level is REPEATABLE_READ. The logic is as under: Transaction begins Read data from Table A If (Table A has Any Data) End Transaction and exit If Table A has No Data, Proceed further ...

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