SQL Server Performance Tuning
How can I determine the maximum value for each data? And which option provides the best performance?
One of the most common requirements is to generate a list of, say, customers along with their last order date. Or, generally speaking, a list of distinct values in one table along with a corresponding maximum value from another table. To solve such problems you basically have three different alternatives. Let’s have a look at […]
When creating temp tables within a stored procedure, is it good practice to drop them as soon as they are no longer required?
Maintaining temp tables uses up SQL Server resources, so the sooner you delete them after you are done using them, the better. For most SQL Servers, there is probably not much of a performance difference if you decide to delete them later than sooner, but on a very busy SQL Server that manages lots of […]
Since functions are not pre-compiled, is there any performance gain from using user-defined functions as opposed to stored procedures?
QuestionI work in a SQL Server environment where we have literally hundreds of stored procedures in one database that are utilized for an OLAP application, and likewise for an OLTP application. I have seen in many instances where a stored procedure is used solely because one can pass parameters to it and use these parameters […]
Question I have a table with over 40 million rows. I would like to partition the table base on the creation date. Does SQL Server support table partitioning? AnswerEven with the fastest hardware and optimally-written queries, there comes a point in the size of a table where there are just too many rows to handle quickly. […]
QuestionI have a “main” table named Property. This table has approximately 60 columns and over 1 million records (this record count will increase significantly over time). Of these 60 columns, approximately 25 are IDs which reference values in multiple different lookup tables. In any given view, query or store procedure, I end up joining 12-25 […]
Generally speaking, if the data you are dealing with is not large, then the table datatype will often be faster than using a temp table. But if the amount of data is large, then a temp table most likely will be faster. Which method is faster is dependent on the amount of RAM in your […]
QuestionBeing a developer, I am not an expert at SQL Server (I know just enough to get done what I need); however, many of our clients are asking us for growth estimations of our database. How much MBs/GBs will a database take up? Also, does SQL Server have the ability to estimate how big it […]
My application makes heavy use of temp tables. Should I be creating temp tables as needed, or should I be using a permanent table over and over instead?
Assuming everything is the same, both tables will produce very similar access speeds. If your application makes heavy use of temp tables, you might consider using a permanent table for these reasons: A regular table already exists. A temp table has to be created, which takes time and overhead. For example, if you need to […]
I don’t know how to transfer an array to a table, and I even if I can, I don’t know if it will be any faster than using INSERT INTO?
QuestionI have an INSERT INTO SELECT query which appends about 500,000 rows of data to a table. The query takes about 22 minutes to run. I would like it to run in less than 5 minutes, if possible.One solution I thought of was to append the 500,000 rows of data to an array (instead of […]
Question The following two queries produce the same results. Is one or the other versions of these two queries more efficient than the other? SELECT DISTINCT productcode FROM sales SELECT productcode FROM sales GROUP BY productcode Answer The goal of both of the above queries is to produce a list of distinct product codes from […]