I am running a MySQL server for tests on a VM (VMWare) with Debian as guest OS. The guest has four emulated CPU cores, so I set thread_concurrency to four. I am doing expensive joins on large tables, ...
I want to know if concurrently UPDATE .... LIMIT N will not overlap with more than one client querying the db. After UPDATE ... LIMIT N the client will make a SELECT with some client_id assigned. I ...
I try to write database code to make sure that it's not subject to race conditions, to make sure that I've locked the correct rows or tables. But I often wonder: Is my code correct? Is it possible to ...
Let's say you have the following code (please ignore that it's awful): BEGIN TRAN; DECLARE @id int SELECT @id = id + 1 FROM TableA; UPDATE TableA SET id = @id; --TableA must have only one row, ...
This is pretty simple, but I'm baffled by what PG does (v9.0). We start with a simple table: CREATE TABLE test (id INT PRIMARY KEY); and a few rows: INSERT INTO TEST VALUES (1); INSERT INTO TEST ...
I'm not very experienced with SQL Server, so maybe I'm missing something My situation is as follows: Session 1 runs a CREATE TABLE (or other CREATE statements) with autocommit off and the CREATE is ...
We are using SQL Server 2008 R2 on a Windows Server 2008 server. We have some main functions which uses some Stored Procedures which has a lot of sub-queries inside of it. I'll take one SP as an ...
When I put my database under a load test (basically just a basic write and basic read from our app), and run show processlist; in the middle of it, there is always 131 rows in the set and that's it. ...