Skip to content

Bits of .NET

Daily micro-tips for C#, SQL, performance, and scalable backend engineering.

  • Asp.Net Core
  • C#
  • SQL
  • JavaScript
  • CSS
  • About
  • ErcanOPAK.com
  • No Access
  • Privacy Policy
SQL

Why COUNT(*) Can Be Slow on Large Tables

- 25.01.26 - ErcanOPAK

Counting rows forces full scans.

SELECT COUNT_BIG(*) FROM Orders WITH (NOLOCK);

Why this matters
On massive tables, counts are expensive — cache or approximate when possible.

Related posts:

SQL: Protecting Sensitive Data with Dynamic Data Masking

SQL COUNT(*) Slows Down Reports

SQL: Eliminating Key Lookups with Covering Indexes (INCLUDE)

Post Views: 7

Post navigation

Use IHttpClientFactory or Face Socket Exhaustion
Use EXISTS Instead of IN for Better Query Plans

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

April 2026
M T W T F S S
 12345
6789101112
13141516171819
20212223242526
27282930  
« Mar    

Most Viewed Posts

  • Get the User Name and Domain Name from an Email Address in SQL (950)
  • How to add default value for Entity Framework migrations for DateTime and Bool (858)
  • Get the First and Last Word from a String or Sentence in SQL (836)
  • How to select distinct rows in a datatable in C# (805)
  • How to make theater mode the default for Youtube (754)
  • Add Constraint to SQL Table to ensure email contains @ (578)
  • How to enable, disable and check if Service Broker is enabled on a database in SQL Server (564)
  • Average of all values in a column that are not zero in SQL (531)
  • How to use Map Mode for Vertical Scroll Mode in Visual Studio (489)
  • Find numbers with more than two decimal places in SQL (447)

Recent Posts

  • C#: Use Init-Only Setters for Immutable Objects After Construction
  • C#: Use Expression-Bodied Members for Concise Single-Line Methods
  • C#: Enable Nullable Reference Types to Eliminate Null Reference Exceptions
  • C#: Use Record Types for Immutable Data Objects
  • SQL: Use CTEs for Readable Complex Queries
  • SQL: Use Window Functions for Advanced Analytical Queries
  • .NET Core: Use Background Services for Long-Running Tasks
  • .NET Core: Use Minimal APIs for Lightweight HTTP Services
  • Git: Use Cherry-Pick to Apply Specific Commits Across Branches
  • Git: Use Interactive Rebase to Clean Up Commit History Before Merge

Most Viewed Posts

  • Get the User Name and Domain Name from an Email Address in SQL (950)
  • How to add default value for Entity Framework migrations for DateTime and Bool (858)
  • Get the First and Last Word from a String or Sentence in SQL (836)
  • How to select distinct rows in a datatable in C# (805)
  • How to make theater mode the default for Youtube (754)

Recent Posts

  • C#: Use Init-Only Setters for Immutable Objects After Construction
  • C#: Use Expression-Bodied Members for Concise Single-Line Methods
  • C#: Enable Nullable Reference Types to Eliminate Null Reference Exceptions
  • C#: Use Record Types for Immutable Data Objects
  • SQL: Use CTEs for Readable Complex Queries

Social

  • ErcanOPAK.com
  • GoodReads
  • LetterBoxD
  • Linkedin
  • The Blog
  • Twitter
© 2026 Bits of .NET | Built with Xblog Plus free WordPress theme by wpthemespace.com