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

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1answer
15 views

Using transactions in sqlplus

I'm coming to oracle from postgresql. In postgresql, I can use the command-line tool, psql, to execute a delete or update in a transaction: dbpool.production=> begin; BEGIN ...
-2
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2answers
29 views

Explicit transactions for each DML query are necessary or not? [on hold]

My question is simple: Which mechanism should I use in databases to ensure that if device shuts down in middle, the process is unified. transactions?
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0answers
19 views

PostgreSQL how to change to Repeatable read [on hold]

I'm running a postgreSQL 9.3 database and I have stored procedures in it. I access the database using JDBC with Java calling the stored procedures with prepared statements. I know that the default ...
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3answers
31 views

Study material for Advanced Databases module inc SQL, Relational Model, ERM & TM [closed]

For my next module in my masters, I am planning on studying Advanced Databases. (Long story short, the masters is designed for people with NON-CS degrees, so I have never studied databases, therefore ...
0
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1answer
179 views

MySQL: Transaction and Deadlock

I have table "tbl_data", where have a lot of rows (3 - 5 million). I have JAVA (*.jar) module from which I INSERT/UPDATE data into this table. If I start *.jar file (for example, "run.jar") and after ...
0
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2answers
22 views

Best way to update the content of large lookups tables

In our application we have a about 20 tables that contain lookup information (read only data that the application doesn't modify). Nightly we'd like to update this information by deleting all the ...
0
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1answer
13 views

Oracle dataguard - Redo apply

In a low bandwidth environment when a transaction commits that generates a large amount of redo data will cause other independent transactions to slow down. This is because the redo data of small ...
1
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1answer
20 views

Does trigger “see” all changes done in the transaction it was fired from?

Let me elaborate on the title. Suppose we have two tables, t1 and t2. t2 has a trigger t2_trgon it. Same transaction inserts/updates data in t1, then does insert/update in t2. t2_trg is fired and ...
1
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1answer
2k views

statistics State in MySQL Processlist

I have a busy MySQL Server having query SELECT sys_sess_state, index_state, timeout_lvl, last_queued_dt, last_polled_wait_dt, create_id, create_dt, modify_id, modify_dt FROM PQR_AM_SYSTEM_SESSION ...
1
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2answers
50 views

Using MySQL/PHP PDO, is there a 'simulate' or dry run option?

Does MySQL (or, ideally, PHP PDO) have some way of simulating transactions without actually committing them? (Can I get MySQL or PDO to act as if data is inserted/deleted/updated, without actually ...
2
votes
2answers
238 views

Separate table for 'scheduled payments' and 'completed payments'?

In a previous financial payments related database I'd worked on, it just had one large transactions table. We would insert scheduled transactions for the future, and when that time came, we'd execute ...
5
votes
1answer
60 views

In Postgres, how to get a list of current defined savepoint?

I'm using postgres SAVEPOINT which create a new savepoint within the current transaction, and would like to display the list of currently defined savepoint in a connection. To be more precise: I'd ...
2
votes
1answer
60 views

How to find the active transactions in VLF?

Is there a way to find the T-SQL statement that is part of the active transaction that is blocking the reuse of the transaction log file VLFs? I am performing tlog backups on every 15 minutes, but ...
1
vote
1answer
33 views

Print, transaction and cursor performance in Transact-sql

I'm having some performance issues when I run a script. I was reading about the problem with print and its performance, but I cannot figure out how to reduce the impact. The algorithm is O(n^2). The ...
4
votes
1answer
241 views

Sql Server - Select while insert on another transaction gives unexpected results

I stumbled at situation that changes my knowledge about transactions and locking fundamentally (I don't know much though), and I need help to understand it. Let's say I have a table like this: ...
2
votes
2answers
126 views

Transaction Log Backups

I am working on backup+recovery scenario and I came across a situation where I could not figure out how I would have to deal with it. We have couple databases where sometimes there may not be any ...
7
votes
3answers
223 views

“When a connection is closed and returned to the pool, the isolation level from the last SET TRANSACTION ISOLATION LEVEL statement is retained”?

The MSDN online article "Snapshot Isolation in SQL Server" states: "An isolation level has connection-wide scope, and once set for a connection with the SET TRANSACTION ISOLATION LEVEL statement, ...
1
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1answer
38 views

Transaction Rollback

I have a purging process that runs to delete old data from table to avoid table growth. My delete statement would be a simple delete based on join something like below Delete FROM TABLE_A A JOIN ...
1
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1answer
109 views

PostgreSQL 9.3: Primary key violated by a trigger INSERT

My problem Consider a table t with many frequent updates from users, from which only the last few are relevant. In order to keep the table size reasonable, whenever a new row is inserted old rows ...
1
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1answer
98 views

Postgres : Executing SELECT within a transaction does not return most recent rows

Given a table layout that looks like this inv_items ========= * id bigserial sku character varying(22) name character varying(32) ... inv_items_stock =============== item_id bigint (inv_items) qty ...
0
votes
2answers
26 views

transaction not processing?

I'm trying to test out an update prior to running it on our production server, however when running my transaction in sqlplus, I don't seem to be able to commit the transaction or get any data back ...
0
votes
1answer
56 views

Is is possible to handle a UserAbort or ClientTimeOut within a Stored Procedure?

An example: create proc [dbo].[usp_SlowProc] as begin try set xact_abort on; -- Ensures rollback on some errors that bypass the try/catch mechanism raiserror('Waiting...', 0, 1) ...
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0answers
64 views

firebird update very slow

I am writing a stored procedure for Firebird 2.5 in which I sometimes need to update a single row in a data table more than once in the same transaction. However, I have noticed that the performance ...
3
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1answer
65 views

Use of Trigger After a Transaction

I have a scenario where there is a transaction being executed to update a few tables. On one of these tables there is a trigger that accesses the data on those tables, but is only planned to be on ...
4
votes
2answers
815 views

Is it possible for SQL Server to miss rows on a select * where PK = “value” query

We have just migrated an application to an SQL Server 2008 R2 from SQL Server 2005 and moved from a physical to virtual hosting environment. I have a very strange error in our application and I was ...
1
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1answer
68 views

How to log within a stored procedure that is encapsulated within a transaction

I have a stored procedure, let us call it sp_A which calls other stored procedures, let us call them sp_B and sp_C. For the sake of consistency an XA TRANSATCION is started within sp_A. What I ...
2
votes
1answer
33 views

MySQL InnoDB transactions with lot of delete instructions

We have a process that runs frequently and does the following steps on a mysql database of type innodb. SET autocommit = 0; DELETE FROM table WHERE category='something'; -- every 300 rows or whatever ...
1
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1answer
37 views

SQL Server: affect other transactions?

I'd be surprised if this existed, but will ask just in case. Is there some mechanism which would allow one transaction to affect another (outside) transaction? For example: BEGIN TRY BEGIN TRAN ...
2
votes
0answers
180 views

Postgresql trigger - get all changed rows after transaction

I have invoice_item table and invoice table. I need to check total price of Order after each transaction. Since I still want to be able to change things, I need trigger after each transaction. CREATE ...
3
votes
2answers
210 views

Synonyms and transactions

I'm working with an application that uses SQL synonyms to switch between tables on local and remote databases without duplicating code. BEGIN TRANSACTION if (@isRemote = 1) BEGIN CREATE ...
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0answers
37 views

Transactions using Isolation Level on databases with FileStream

We have a highly transactional application. We have a requirment to upload huge data into our database that can happen for a duration of 5-10 minutes. During our upload time, the tables are getting ...
0
votes
1answer
83 views

Is UDPLOCK using Row-locks?

I have a UPDATE statement that is using a UPDLOCK inside a DTCTransaction to avoid deadlocks. Now I was wondering. is it locking on a Row-level or on a Table-level?
0
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0answers
68 views

Transaction log backups during index maintenance

We have a database with large and complex files and fragmented indexes. The environment is SQL 2008 Full recovery model and Mirrored which limits me to reorganizing. The backup strategy is Full ...
2
votes
1answer
34 views

Reading from subscriber during Transactional Replication

When using Transaction Replication, are there any restrictions around selecting data from the subscriber whilst transactions are being applied to it? i.e. can selects be made against tables to which ...
3
votes
1answer
364 views

Complex constraint across all data in a table

We have a table to record processing that occurs on a system and we need to ensure that only a single row has an 'in process' status. I want to ensure that the result of this is always either zero or ...
7
votes
1answer
487 views

Synchronization using triggers

I have a requirement similar to previous discussions at: Writing a simple bank schema: How should I keep my balances in sync with their transaction history? Trigger in combination with transaction ...
0
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0answers
120 views

Avoid transaction rollback when Deadlock is encountered (mysql)

I'm currently trying to handle concurrent inserts correctly using MySQL, I'm basically doing the following: CREATE TABLE foo (id INT NOT NULL PRIMARY KEY) ENGINE=INNODB; CREATE TABLE bar (id INT NOT ...
2
votes
1answer
36 views

MySQL behaviour on connection failure

My MySQL database is hosted on a different machine from my application system, which issues queries to the MySQL database remotely. If for some reason the network connection between the two machines ...
1
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1answer
76 views

How does the transactions interact if you set a different isolation level per connection?

I read that I can have different isolation levels per connection and in the server. The default isolation level is REPEATABLE-READ. So if I have a transaction that issues a SERIALIZED to the client ...
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votes
2answers
91 views

When do I need transactions /locks?

I know that transactions are meant to group several operations as one. But if for example in the same table one transaction does DELETE FROM table where state = 'done' and another does either SELECT ...
0
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0answers
144 views

When is transaction removed from sys.dm_tran_active_transactions?

We are having some issues with clients getting Transaction Timeout when connecting to our clustered SQL Server 2008 R2. To investigate the problems I have been digging into ...
0
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0answers
46 views

Why does the delete/update block each other in this case?

The following drives me crazy. I have: session1>begin; session2>begin; session2>update dummy set salary=1000 where id=11; session1>delete from dummy where id=1; id is the PK ...
0
votes
1answer
495 views

Rollback parent procedure on failure in MySQL

I have the following two procedures on my server: CREATE DEFINER=`someone`@`localhost` PROCEDURE `NewMagnet`( IN `nick` VARCHAR(32), IN `tth` CHAR(39), IN `name` TINYTEXT, IN ...
0
votes
1answer
95 views

How to set isolation to SERIALIZABLE DEFERRABLE for a whole Postgresql database? [closed]

I think read somewhere that it was possible to configure a Postgresql database to force all transactions to be SERIALIZABLE, but I can't find that document anymore. In fact, I would like to force the ...
1
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2answers
254 views

Are MySQL transactions under-utilised?

I have a vague understanding of transactions that it means you can help the server understand that a series of queries are related. Scenario : Suppose I have a series of queries which creates a user ...
0
votes
1answer
67 views

How to ensure a trigger is fired after variable number of inserts?

I have a 1:N relationship between two tables - let's call them "foo" (the parent table) and "bar". I have some triggers on both "foo" and "bar" tables. I insert data in a single transaction, first to ...
0
votes
1answer
67 views

Case of irrecoverable error in transaction

According to an exam question,which may lead to an irrecoverable error: 1.A transaction writes a data item after it is read by an uncommitted transaction. 2.A transaction a data item after it is ...
1
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2answers
78 views

Transaction basics. What is the result of 2 transactions running concurrently?

I have a rather basic question on transactions. Assume a table Account with a column amount. Now we have the following code: BEGIN $amount = SELECT amount FROM ACCOUNT WHERE id = 123; $amount = ...
12
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5answers
3k 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?
1
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1answer
174 views

What happens to a transaction if the network connection fails?

What happens to a transaction when the client connection is lost. Example the client is a web application code that starts a transaction to a remote server instance. The client sends the sql code to ...