Aaron Bertrand in SQL Server

How to optimize planned availability group failovers in SQL Server

Learn how to perform fast and predictable SQL Server planned Availability Group (AG) failovers. Discover tips to reduce downtime, optimize...

20 February 2026 15 min read

Aaron Bertrand in SQL Server

How to fix the Invalid Length error in SQL Server

Learn why SQL Server throws the invalid length error in functions like LEFT, SUBSTRING, and RIGHT, and discover practical fixes...

12 January 2026 5 min read

Aaron Bertrand in SQL Server

How to fix the Invalid Object Name error in SQL Server

Learn why SQL Server shows ‘Invalid object name’ errors and how to fix them. Common causes include typos, missing objects...

18 December 2025 6 min read

Aaron Bertrand in Featured

Common SQL Server Problems: Network Related or Instance Specific Error Occurred

This is the first in a series of articles meant to provide practical solutions to common issues. In this post,...

07 July 2025 6 min read

Aaron Bertrand in SQL Server

SQL Server 2025 ZSTD Backup Compression Guide

SQL Server 2025 adds Zstandard (ZSTD) backup compression with LOW, MEDIUM, and HIGH levels. Compare ZSTD vs MS_XPRESS performance, syntax,...

11 June 2025 15 min read

Aaron Bertrand in T-SQL Programming

Five SQL Server Changes: DROP_EXISTING, ALTER TABLE, STRING_SPLIT Fixes

Aaron Bertrand on five SQL Server behaviours he'd like Microsoft to fix: DROP_EXISTING needing an existing index, ALTER TABLE DROP...

01 January 2025 5 min read

Aaron Bertrand in SQL Server

Storing Weekday Sets in SQL Server Using Bitwise Flags: Schedules and Recurring Jobs

Store and query sets of weekdays in SQL Server using bitwise flags - each day encoded as a power of...

02 August 2024 7 min read

Aaron Bertrand in T-SQL Programming

Index cleanup : Harder than it looks

I’m not the first person to write about cleaning up unused or redundant indexes. You can read many articles about...

22 July 2024 7 min read

Aaron Bertrand in Database Administration

It’s a recovery strategy, not a backup strategy

I’ve talked about it before; you shouldn’t have a backup strategy, you should have a recovery strategy. I can’t possibly...

08 July 2024 12 min read

T-SQL Programming

Aaron Bertrand in T-SQL Programming

Snake Draft Sorting in SQL Server Part 4: Coordinating Parallel Job Completion

Part 4 of the snake-draft sorting series - coordinating parallel SQL Agent jobs when work units finish at different times....

27 May 2024 9 min read

T-SQL Programming

Aaron Bertrand in T-SQL Programming

Snake Draft Sorting in SQL Server Part 3: Balancing Work Across Tables Within One Database

Part 3 of the snake-draft sorting series - extending the technique from balancing work across databases (parts 1-2) to balancing...

15 May 2024 5 min read

T-SQL Programming

Aaron Bertrand in T-SQL Programming

Snake draft sorting in SQL Server, part 2

Part of a series: [ Part 1 | Part 2 | Part 3 | Part 4 ] In my previous...

15 April 2024 7 min read

T-SQL Programming

Aaron Bertrand in T-SQL Programming

Snake Draft Sorting in SQL Server: Distributing Workloads Evenly (Part 1)

Snake draft sorting in SQL Server divides processing tasks into evenly-distributed groups by assigning work in a serpentine order. Part...

12 April 2024 8 min read

T-SQL Programming

Aaron Bertrand in T-SQL Programming

SQL Server Pagination Performance: Sorting by Large Text Columns

SQL Server OFFSET-FETCH pagination becomes extremely slow when sorting by large text columns (varchar(max), nvarchar(max)). Learn to fix it using...

25 March 2024 9 min read

Database Administration

Aaron Bertrand in Database Administration

Get the most out of SQL Server Agent logs

If you haven’t migrated your workloads to a managed database platform yet, you’re probably still relying on SQL Server Agent...

11 March 2024 6 min read

Database Administration

Aaron Bertrand in Database Administration

Upgrade SQL Server on your workstation

Lately, I’ve seen many people struggling to upgrade their workstation to the latest version of SQL Server. The main source...

26 February 2024 6 min read

Database Administration

Aaron Bertrand in Database Administration

Leave it better than you found it

This is for the folks who still have to log into remote machines and do work manually on the box....

12 February 2024 8 min read

Database Administration

Aaron Bertrand in Database Administration

Optimized locking in Azure SQL Database

I don’t think I’ve ever had a great impression of Azure SQL Database as a place for production applications. In...

08 January 2024 8 min read

T-SQL Programming

Aaron Bertrand in T-SQL Programming

Counting more efficiently

Nearly a decade ago, I wrote a post called “Bad habits : Counting rows the hard way.” In that post,...

20 December 2023 7 min read

T-SQL Programming

Aaron Bertrand in T-SQL Programming

When an update doesn’t update

Tell me if you’ve heard this one before: I changed data from my application, but when I checked the database,...

27 November 2023 5 min read

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Aaron Bertrand

Aaron's content

How to optimize planned availability group failovers in SQL Server

How to fix the Invalid Length error in SQL Server

How to fix the Invalid Object Name error in SQL Server

Common SQL Server Problems: Network Related or Instance Specific Error Occurred

SQL Server 2025 ZSTD Backup Compression Guide

Five SQL Server Changes: DROP_EXISTING, ALTER TABLE, STRING_SPLIT Fixes

Storing Weekday Sets in SQL Server Using Bitwise Flags: Schedules and Recurring Jobs

Index cleanup : Harder than it looks

It’s a recovery strategy, not a backup strategy

Snake Draft Sorting in SQL Server Part 4: Coordinating Parallel Job Completion

Snake Draft Sorting in SQL Server Part 3: Balancing Work Across Tables Within One Database

Snake draft sorting in SQL Server, part 2

Snake Draft Sorting in SQL Server: Distributing Workloads Evenly (Part 1)

SQL Server Pagination Performance: Sorting by Large Text Columns

Get the most out of SQL Server Agent logs

Upgrade SQL Server on your workstation

Leave it better than you found it

Optimized locking in Azure SQL Database

Counting more efficiently

When an update doesn’t update