Filesystem superblocks and their backup copies
I’d like to understand how (modern) filesystems are implemented and having trouble to fully understand superblocks and their backups. I reference ext4 and btrfs, but the questions may also apply to...
View ArticleTransaction with multiple SQLCMD calls in a batch file
Is there a good way to do something like the following? SQLCMD -S %SERVER% -E -Q "BEGIN TRANSACTION" FOR %%f in (script1 script2 script3) do ( SET CURRENT_SCRIPT=%%f SQLCMD -S Localhost -E -b -V 1 -i...
View ArticleCan I select data inserted in the same uncommited transaction?
Maybe this is a dumb beginner question, but I cannot find an answer anywhere. Everywhere I read about the Transaction Isolation which solves the visibility of data within the concurrent transactions....
View ArticleTransactional DDL workflow for MySQL
I was a little surprised to discover that DDL statements (alter table, create index etc) implicitly commit the current transaction in MySQL. Coming from MS SQL Server, the ability to do database...
View ArticleDoes MySQL support querying for the current running transaction id
PostgreSQL supports retrieving the current running transaction id using a query like this: select txid_current(); Does MySQL have any such equivalent?
View ArticleWhat is the usefulness of transactions in a batch (especially a Spring batch)?
I understand what a transaction is in a web application, where you have some groups of database interactions which have to fail or succeed together so the database is always in coherent state. But why...
View ArticleTransactions and subresources with JAX-RS
I’m porting an existing application RESTful API to a Java web framework — I don’t actually care which — but it’s proving hard to get the basics right. The core of the problem appears to be getting the...
View ArticleMySQL: Why is inserting data with transactions faster then without them
I am using stored procedure to generate sequence consisting of prefix and number in given range (etc sequence “AB100″, “AB101″, …, “AB199″, “AB200″) The stored procedure includes REPEAT loop, in which...
View ArticleLocking issues under transaction on Postgres
I recently got a “Out of shared memory – You might need to increase max_locks_per_transaction” error. This is a long running process where I import a bunch of CSV files after proper processing. I loop...
View ArticleSSIS 2005 Truncate Table
when I switch from “delete from” statement to a “truncate table” statement in a transactional sequence container, Data flow remains yellow in execution. any ideas ? thanks
View ArticleSQL Server Log Shipping Randomly Stops Copying and Restoring
I’m fairly new to Log Shipping but have configured a few with no issues, however I have a server sitting on SQL 2008 R2 with 6 databases on there, all 6 of these are supposed to be log shipping. The...
View ArticleWhy are SELECT queries in sleeping status holding open transactions
Using sp_WhoIsActive, I see that I have a lot of processes in a “sleeping” status, several for hours. I am not sure of the cause and am still troubleshooting (timeout? bad code with uncommitted...
View ArticleMySQL SELECT blocking an INSERT?
Is it possible for a SELECT query to block INSERT / ALTER queries? I have the following (taken from ENGINE INNODB STATUS) on my slave database: ---TRANSACTION 26DA7060, not started mysql tables in use...
View ArticleMysql transaction READ REPEATABLE and READ COMMITTED read view
I’ve come across something strage using Amazon RDS (MySQL 5.6.23). I had issues when concurrent transactions were locking and then calculating a value from multiple tables. The following is a quick...
View ArticleTrigger/Event that fires when a Transaction finishes
I have a query that pulls from about 15 different tables. I am looking to materialize this into a table that stores it in xml/json. (To improve performance.) The problem I have is that these tables are...
View ArticleCLR/C# equivalent to XACT_STATE()
I am porting a set of T-SQL stored procedures to C#/CLR. In the T-SQL, we use XACT_STATE() to determine if an error requires rolling back to a savepoint or rolling back the transaction entirely. I...
View ArticleMySQL Commited data not seen to select query
Context: The framework used is Spring and all queries are run with JdbcTemplate. Mysql Server version is 5.6.19. The table is an InnoDB table and defaults like auto commit and isolation level...
View ArticlePostgreSQL visibility of records changes from other transaction inside the...
I have a table “tst” which has a “status” column using which we process records in that table. Once the records are processed we set the status to ‘Y’; #d tst Table "core.tst" Column | Type | Modifiers...
View ArticleHow do workflow tools (jBPM) keep transactional state consistent?
I’m looking at jBPM specifically, but I think this applies with other systems too. As I understand it.. When placing an item into a workflow, one does not generally put a reference to that item, one...
View ArticleForcing MS SQL Server to rollback on error
I am having some problem to understand how transactions work on SQL Server, even after I thought I had all answers from the documentation. To put it simply, I have a transaction at the beginning of a...
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