We have a passwords table which references a user table. Records never get deleted from the password table so if a user changes their password, a new entry with a more recent Created date gets inserted. The hash of the password is salted with various things, most importantly the created date of the actual record. […]
I have a somewhat complex query with roughly 100K rows. The query runs in 13 seconds in SQL Server Express (run on my dev box) The same query with the same indexing and tables takes over 15+ minutes to run on MySQL 5.1 (run on my production box – much more powerful and tested with […]
I have a stored procedure on SQL Server 2005. It is pulling from a Table function, and has two joins. When the query is run using a load test it kills the CPU 100% across all 16 cores! I have determined that removing one of the joins makes the query run fine, but both taxes […]
I seem to be facing a strange issue in SQL 2008. I have a query which runs fine and fast from query analyser, but times out if run through a stored procedure! The SP just starts with this query and has no other code before this query SELECT col1,col2 FROM TBL1 (nolock) INNER JOIN TBL2 […]
I’m currently working on a project where we have a large data warehouse which imports several GB of data on a daily basis from a number of different sources. We have a lot of files with different formats and structures all being imported into a couple of base tables which we then transpose/pivot through stored […]
I have a list of upwards 3,000 decimal values and for each one I need to lookup another decimal value from a SQL Server database. Currently I’m using the .Net SqlClient classes. Making 3,000 queries seems inefficient, but I’m not sure if there’s a neat efficient way of combining the queries into few calls. The […]
In my current project, some tables have a column named “changed”, which indicates if the the current line had been changed since the last check. All the insert and update statements includes this column. Every hour, I run a schedulated task that queries all changed rows, do some stuff with those rows and then sets […]
Our primary database server is an 8 core box with 8GB of RAM. The CPU is a Xeon E7330 @ 2.4GHz. It runs Windows Server 2003 R2 (x64 edition) and SQL Server 2005 I wanted to do some testing so I set up SQL Server 2005 on another brand-new server which is an 8 core […]
Any good articles out there comparing Oracle vs SQL Server vs MySql in terms of performance? I’d like to know things like: INSERT performance SELECT performance Scalability under heavy load Based on some real examples in order to gain a better understanding about the different RDBMS.
Anyone have any recommendations for books about performance tuning on either frontend or backend? I’m looking specifically for asp.net or sql (MS-SQL) performance tuning, but anything is good to go. Thanks!