Missing Indexes in MS SQL or Optimization in no Time

When executing a query, the SQL Server optimizer tries to find the best query plan based on existing indexes and available latest statistics for a reasonable time, of course, if this plan is not already stored in the server cache. If no, the query is executed according to this plan, and the plan is stored in the server cache. If the plan has already been built for this query, the query is executed according to the existing plan.

We are interested in the following issue:

During compilation of a query plan, when sorting possible indexes, if the server does not find the best index, the missing index is marked in the query plan, and the server keeps statistics on such indexes: how many times the server would use this index and how much this query would cost.


SQL Server Index Backward Scan: Understanding, Tuning

Table indexing strategy is one of the most important performance tuning and optimization keys. In SQL Server, the indexes (both, clustered and nonclustered) are created using a B-tree structure, in which each page acts as a doubly linked list node, having an information about the previous and the next pages. This B-tree structure, called Forward Scan,  makes it easier to read the rows from the index by scanning or seeking its pages from the beginning to the end. Although the forward scan is the default and heavily known index scanning method, SQL Server provides us with the ability to scan the index rows within the B-tree structure from the end to the beginning. This ability is called the Backward Scan. In this article, we will see how this happens and what are the pros and cons of the Backward scanning method. (more…)

Creating Dynamic Pivot Table with QUOTENAME Function

In my previous article on the basic pivot operator, we saw how pivot operator could be used to convert rows to columns, resulting in pivot tables. We saw that there were three main steps to create a pivot table. The first step was selecting the base data. The second step was converting the base data to a table-valued expression, and the final step involved applying a pivot operator to the temporary data, which resulted in the pivot table.


Methods to Rank Rows in SQL Server: ROW_NUMBER(), RANK(), DENSE_RANK() and NTILE()

SQL Server provides us with a number of window functions that help us to perform calculations across a set of rows, without the need to repeat the calls to the database. Unlike the standard aggregate functions, the window functions will not group the rows into a single output row, they will return a single aggregated value for each row, keeping the separate identities for those rows. The Window term here is not related to the Microsoft Windows operating system, it describes the set of rows that the function will process.


Setting Database Access Permissions

Server security mainly depends on how correctly you can configure access permissions on objects. Providing a user with excessive permissions may cause many issues. No, a user will not use your errors. Instead, any hacker or I will do this. In this case, you can forget about your tables with data or the whole database.

For some reason, the security of the database is protection from the outside, such as a hacker. However, this happens very seldom. I am a programmer in a big company and an administrator does not even think about protecting the server ports, where everything is open. There is a bunch of databases, programs, and even an FTP server on a single server and it has never been hacked over the past 5 years. Fortunately, I persuaded the administrator to deploy the WEB server on a separate hardware. Otherwise, if someone knew the IP address of our main server, any slacker would be able to hack it. Neither the database nor Windows has been patched for several years.


Sending a Query to All Databases of All Specified Servers in MS SQL Server and C#.NET

Often, it is necessary to send a query to all databases of all specified servers. Many DML-queries can be created with built-in tools. However, what about DDL-queries?

In this article, we are going to explore an example of implementing the application that sends a query to all databases of all specified servers, using MS SQL Server and C#.NET.