SQL DBA Blog: Home
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Add a Filegroup to a SQL Server Database
ADD FILEGROUP then ADD FILE, and the trap in between: a filegroup with no files will accept a CREATE TABLE and only fail at the first INSERT with Msg 622. Placing objects, changing the default, and removing one again.
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Set the Default Database for a SQL Server Login
One line sets a login default database, and SQL Server never checks that the login can actually use it. The failure arrives at the next connection, with the same message whether the database is gone or just inaccessible.
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SQL Server High CPU: What to Check First, in Order
SQL Server at 100 percent CPU describes four different problems. The five checks that separate them, in the order that finds the fault fastest, each handing off to the script that does the work.
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Cannot Connect to SQL Server: The Checks in the Order That Finds It
A network-related or instance-specific error, error 53, error 40, error 26: which one you have decides where to look. The connection checks in the order that finds the fault, each one linking to the full fix.
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Cumulative Wait Stats Lie: Measuring Waits Over an Interval
Wait statistics accumulate from startup, so on a long-running instance they describe history rather than the problem in front of you. Two snapshots and a subtraction fix that.
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SQL Server Differential vs Log Backup: Which One Restores What, and How the Chain Breaks
Mid restore is the wrong moment to work out how differential and log backups differ. What each one contains, which files you actually need, and the trap that any ordinary full backup taken by anyone silently becomes the new base for your differentials.
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SQL Server MAXDOP and Cost Threshold: What To Set, and Why 5 Is Not a Recommendation
Two settings decide when SQL Server splits a query across processors, and both ship with values you are probably meant to change. Microsoft’s current MAXDOP table, what they actually say about cost threshold, and why CXPACKET is no longer the evidence it used to be.
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SQL Server Log Won’t Truncate: What log_reuse_wait_desc Is Telling You
A transaction log is filling a disk and the backup job says it succeeded. SQL Server already knows why it cannot reuse the space, and it tells you in one column of sys.databases.
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sp_who vs sp_who2 vs sp_whoisactive in SQL Server
Ever wondered what is happening inside your SQL Server instance right now? sp_who, sp_who2 and sp_whoisactive all answer that question, at very different depths. The first ships documented, the second ships undocumented but better, and the third is a free community procedure that most working DBAs treat as the real answer. This post is the…
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The Evolution of SQL Server: Every Version from 1989 to 2025
🕐 Version history, with the support dates that actually matter Every release from the 1989 OS/2 original to SQL Server 2025, what each one changed for the people running it, and which ones are still receiving security updates today. Lifecycle dates checked against the builds and lifecycle reference, which is regenerated after each patch release.…
- Add a Filegroup to a SQL Server Database
- Set the Default Database for a SQL Server Login
- SQL Server High CPU: What to Check First, in Order
- Cannot Connect to SQL Server: The Checks in the Order That Finds It
- Cumulative Wait Stats Lie: Measuring Waits Over an Interval
- SQL Server Differential vs Log Backup: Which One Restores What, and How the Chain Breaks
- Backups & Recovery (17)
- DBA Scripts (150)
- High Availability (HA) (12)
- Installation & Configuration (45)
- Maintenance (24)
- Migration & Upgrades (14)
- Monitoring (9)
- Performance Tuning (37)
- Security (Encryption & Permissions) (19)
- Storage & Capacity (15)
- T-SQL Fundamentals (11)
- Troubleshooting (65)
- Wait Types (235)