“I/O is frozen on database” and “I/O was resumed on database”? Did you check the air conditioner temperature? Let us learn about it in today’s blog post.
Scheduler ID Values in dm_os_schedulers: What the Big Numbers Mean
Scheduler ID values in dm_os_schedulers run from 0 up to a few thousand, and then jump past one million. This post groups the rows into user, dedicated admin connection and hidden schedulers, and shows the filter that keeps CPU scripts honest. It also shows why filtering on the number alone is fragile.
Active and Inactive VLFs: List Them for Every Database
To list active and inactive VLFs for every database, count the rows of sys.dm_db_log_info by vlf_active and read the log reuse wait next to them. This post builds a demo log with 24 VLFs, shows how an open transaction and small autogrowth steps add more, and fixes the count with one shrink and one regrow.
KEEP PLAN Hint: Cut Temp Table Recompiles in SQL Server
The KEEP PLAN hint gives a temp table the same recompile threshold as a permanent table. This post counts statistics recompiles with Extended Events for a plain query, a KEEP PLAN query and a KEEPFIXED PLAN query. It shows where the hint helps, where it does nothing and what the stronger hint costs.
Proving a Tuning Change Worked With Before and After Numbers
Prove a tuning change with before and after numbers from Query Store for CPU, reads, duration, and comparable execution volume.
Msg 17177 in the SQL Server Error Log: What It Means
Msg 17177 is an informational line in the SQL Server error log that reports the process ID of the instance. This post explains its two forms, a daily line and a start-up line, and reads both with a short query. It also shows how the line reveals uptime, downtime and the time zone of the server.
How to Do Case Insensitive Search? – Interview Question of the Week #267
Question: How to Do Case Insensitive Search?
Collations in SQL Server provide sorting rules, case, and accent sensitivity properties for your data.