transaction-isolation Questions
8
Solved
With SQL Server's transaction isolation levels, you can avoid certain unwanted concurrency issues, like dirty reads and so forth.
The one I'm interested in right now is lost updates - the fact two...
Algonquin asked 20/11, 2011 at 12:19
4
Solved
I've been reading up on PostgreSQL transaction isolation and how that relates to Django's transaction.atomic() (e.g. this article, PostgreSQL docs), but I'm far from fluent in this topic and I'm no...
Overeat asked 5/6, 2023 at 13:47
12
Solved
What is the difference between non-repeatable read and phantom read?
I have read the Isolation (database systems) article from Wikipedia, but I have a few doubts. In the below example, what will ha...
Defile asked 15/6, 2012 at 1:54
5
Solved
The PostgreSQL manual page on the Serializable Isolation Level states:
[Like] the Repeatable Read level, applications using this level must be prepared to retry transactions due to serialization...
Fairing asked 9/10, 2011 at 17:39
3
Solved
I see an error message related to transaction isolation levels. There are two tables involved, first one is updated frequently with transaction isolation level set to SERIALIZABLE, the second one h...
Marcelenemarcelia asked 24/2, 2011 at 9:0
1
Solved
The REPEATABLE_READ transaction isolation level of PostgreSQL 12 prevents dirty reads, non-repeatable reads, and phantom reads. In contrast to the READ_COMMITTED isolation level, the REPEATABLE_REA...
Iinden asked 10/10, 2021 at 13:54
3
Solved
I've heard about many application developers having a bit of trouble in regards to race conditions in database processing. A typical example goes something like this:
User 1 selects a field, say,...
Diaconicum asked 24/3, 2012 at 8:46
1
Solved
Does a SELECT query following an INSERT … ON CONFLICT DO NOTHING statement always find a row, given the default transaction isolation (read committed)?
I want to INSERT-or-SELECT a row in one table...
Devy asked 4/9, 2021 at 2:30
2
I want to try transaction isolation using PostgreSQL with pgadmin. First I inserted a new record inside BEGIN but without COMMIT.
BEGIN;
INSERT INTO my_table(id,value) VALUES (1,'something');
//U...
Brackely asked 11/11, 2015 at 7:33
2
I've read Martin Fowler's book chapter Optimistic Offline Lock
Author describes following example(if I understood it correctly):
There are 2 entites: Order and Client. There are 2 transactions(bu...
Brucite asked 14/10, 2019 at 21:13
2
Solved
I have set isolation level in C# code as readcommitted, and I am calling a stored procedure which is timing out due to some reason. The stored procedure does not have any set isolation level statem...
Sunglasses asked 21/5, 2019 at 18:48
2
Solved
When using SERIALIZABLE transactions to implement a pattern of inserting a value into a database only if it does not already exist, I have observed a significant difference between MySQL and Postgr...
Allgood asked 21/3, 2018 at 18:55
1
I'm looking to ensure isolation when multiple transactions may execute a database insert or update, where the old value is required for the process.
Here is a MVP in python-like pseudo code, the ...
Amata asked 26/1, 2018 at 0:0
1
I have MySQL Workbench (community-6.2.3) installed in a Ubuntu system using .deb.
Workbench session does not seem to see updates (DML) to the database done by other sessions (applications/command ...
Ignition asked 5/10, 2014 at 22:47
2
Solved
I'm trying to figure out if the query below is safe to use for the following scenario:
I need to generate sequential numbers, without gaps. As I need to track many of them, I have a table holding ...
Brewmaster asked 20/10, 2016 at 19:28
1
I want to make my application serialize every transaction by default. I'd then relax isolation based on performance measurements and knowing what data particular actions/transactions use and change...
Spiniferous asked 11/4, 2015 at 21:33
2
Solved
I have the following code:
set transaction isolation level read committed; --this is for clarity only
DECLARE @jobName nvarchar(128);
BEGIN TRAN
SELECT @jobName = JobName
FROM dbo.JobDetails
...
Haughay asked 2/9, 2016 at 7:31
3
Solved
According to the UPDATE documentation, an UPDATE always acquires an exclusive lock on the whole table. However, I am wondering if the exclusive lock is acquired before the rows to be updated are de...
Villosity asked 8/1, 2016 at 14:29
2
Solved
In the PostgreSQL documentation about transaction isolation levels, we can read the following:
While performing all permanent database writes within Serializable transactions on the master will ...
Finnougrian asked 3/3, 2015 at 13:56
2
Solved
Quote from http://www.postgresql.org/docs/9.4/static/transaction-iso.html :
When you select the level Read Uncommitted you really get Read Committed, and phantom reads are not possible in the P...
Caulicle asked 5/6, 2015 at 14:23
2
I would like to know different isolation levels with respect to commit, and would also like to know about row-level and table-level lock.
Bridgid asked 30/11, 2012 at 14:57
2
We have a table in MySQL using InnoDB, and we are using a transaction isolation level of read uncommitted. Why does setting @x as shown acquire a lock?
mysql> set @x = (select userID from user...
Drench asked 31/10, 2012 at 5:37
3
Solved
I am working on DW project where I need to query live CRM system. The standard isolation level negatively influences performance. I am tempted to use no lock/transaction isolation level read uncomm...
Andrus asked 7/3, 2014 at 8:57
1
We have set the following in the my.ini file
[mysqld]
transaction-isolation = READ-COMMITTED
We assume this setting will be the default for all user sessions.
When logging in using PHPMyAdmin th...
Presbyterial asked 5/12, 2013 at 9:17
1
Solved
I am using Spring transaction management to control a application with hibernate, it uses two instance of threads to access concurrency database and modify one table. It is ensuring that the values...
Doge asked 6/11, 2012 at 18:7
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