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

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4
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3answers
934 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 ...
2
votes
1answer
1k views

MySQL Insert into two tables using new IDs

I'm trying to select data already in the database and insert it into two tables using the generated ID from table one. table1 contains configuration options, table2 contains pricing data. Table2 uses ...
0
votes
0answers
96 views

Being careful about additional records being added in a duplicate record merge?

We have a multi-user MS-Access 2003 database. Connecting to it using SQuirrel SQL, and the JDBC/ODBC bridge, I've managed to eek transactions of some sort out of JET by turning off autocommit. I've ...
1
vote
2answers
819 views

mysql transaction vs lock

I have a question regarding MySQL locking and transaction management. My Question is ..does mysql takes lock on the the tuple/table on which I am doing select/update in a transaction ?
3
votes
1answer
206 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
2answers
2k 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 ...
0
votes
1answer
303 views

Can I rollback/abort a transaction if no rows were inserted?

I have a transaction in which I want to do something like this: START TRANSACTION; INSERT INTO table1 (...) SELECT ... FROM table 2; ... if select count(*) from table1 returns 0 abort/rollback ... ...
4
votes
1answer
3k 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 ...
10
votes
1answer
377 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 ...
2
votes
1answer
578 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 ...
1
vote
1answer
152 views

timestamp based concurrency

I am wondering if someone could help me out with a question I have about time stamp based concurrency. I found the following practice problem on a website It basically asks which of the following ...
2
votes
1answer
846 views

Transaction Lock Timeouts When Updating a Row

I'm trying to determine the cause of an InnoDB transaction lock timeout. This one is very strange in that it appears to be a deadlock error instead - nonetheless, here's the output of my slow log ...
2
votes
1answer
792 views

Rotate a table in PostgreSQL

Problem description I need to rotate (with DROP and CREATE) a table which is heavily used by other clients. At present, I have a program which replaces (DROP + CREATE) this table. Sometimes, just ...
3
votes
3answers
494 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, ...
4
votes
2answers
312 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 ...
1
vote
1answer
158 views

Unit testing with InnoDB transactions

So, I'm running some unit tests against some InnoDB tables in MySQL. Each unit test is wrapped in a transaction: setUp: SET autocommit = 0; SET SESSION TRANSACTION ISOLATION LEVEL SERIALIZABLE; ...
1
vote
2answers
165 views

INSERT statements in a transaction and locking a range of rows

I have a table that is concurrently accessed by many users. Typically, INSERTs to the table are made one at a time. Occassionaly, users will add a "batch" of rows at the same time. The batch is ...
2
votes
1answer
242 views

select for update gives error on indexed column

here is my code: mysql_query("start transaction"); $q="select max(id) from test for update"; $r=mysql_query($q); $row=mysql_fetch_array($r); for ($k=0;$k<100000;$k++) { $q="insert into test values ...
5
votes
1answer
197 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 ...
3
votes
2answers
2k 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 ...
5
votes
1answer
180 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, ...
2
votes
1answer
826 views

Save Transaction: Is the name local to the stored procedure or not?

Some foot shooting just occured on a production server. I fixed the problem, but I'm now rather confused. There is a subset of stored procedures that preserve state on failure. That is, if the ...
8
votes
1answer
2k 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 ...
4
votes
2answers
896 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 ...
3
votes
2answers
372 views

read before write transaction

Talking about transactions (db transactions), does a read operation have always precede a write operation? That's obvious, isn't it? Thanks in advance *Of course my question doesn't take into ...
0
votes
1answer
73 views

Transaction question

I have a question. c stands for Commit, a stands for Abort, T is a transaction (db Transaction) Is the following sentence true? either c or a belong to T In my opinion the sentence is true since ...
0
votes
1answer
1k views

how to make a table unlocked within transaction block

I am using SQL Server 2008. I have several stored procedures that process different reports. Each stored procedure makes use of Begin Transaction' and 'Commit Transaction, using the default ...
4
votes
2answers
7k 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 ...
4
votes
1answer
829 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 ...
1
vote
1answer
129 views

Overlapping Transactions

Apolgies in advance if this has been discussed before, or is even fundamental enough for it to be outlined on, say, Wikipedia. I just felt that asking would be more efficient! Anyway, I want to ask ...
1
vote
2answers
793 views

SQL Server 2008 R2 - How to check Foreign Key constraints in a transaction only when committed?

We are synchronizing tables between two databases (yes, it needs to be done by our software and not by replication etc.) Both databases are identical with many foreign-key constraints on tables. ...
3
votes
1answer
243 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 ...
4
votes
2answers
1k 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 ...
7
votes
1answer
3k 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. ...
3
votes
1answer
532 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 ...
7
votes
2answers
188 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 ...
6
votes
3answers
2k 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 ...
12
votes
5answers
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?
2
votes
1answer
388 views

Locking, deadlocking workaround while process data at the same table

My database has a table: tableX. Task1 makes intensive INSERTs (1000 records per minute) as records to process and very seldom UPDATEs (1-2 records per minute) as records to recalculate. At the ...
20
votes
3answers
14k 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 ...
3
votes
1answer
211 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
394 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. ...
7
votes
1answer
2k 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 ...
15
votes
3answers
19k 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 ...
3
votes
1answer
740 views

Duplicate UNIQUE KEY error after ROLLBACK in MySQL

I have a table like this mysql> describe seudonimos; +--------------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra ...
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 ...
2
votes
1answer
400 views

SQL Server Logon Trigger causing problems with the Distributed Transaction Coordinator

I've created the following simple logon trigger on my SQL Server 2005: CREATE TRIGGER LOGON_RESTRICTION ON ALL SERVER FOR LOGON AS BEGIN PRINT 'Hello World' END GO Which seems to be working fine ...
1
vote
2answers
1k views

Distributed Transactions between SQL Server 2000 & MySQL Stopped Working

We have been successfully copying data from a MySQL Slave database into a SQL Server 2000 database. The MySQL server is a linked server. I have tried using v3.51 and v5.1.8 of the ODBC connector ...
6
votes
6answers
3k 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 ...
1
vote
1answer
500 views

Is it possible to write an SQL query that automatically reconciles/“transactionalizes” payments and charges

I'm still working on the project mentioned here (http://dba.stackexchange.com/questions/2428/how-do-i-properly-design-a-many-to-many-charges-payments-accounting-system). The system is to give the ...