Group by query hash to add up every cached copy of one query. See why the top query hides across entries in SQL Server.
One Query Many Plans – SQL in Sixty Seconds #171
After the blog post, lots of people asked me it will be more helpful if I can create a video on the same topic of one query many plans.
Read-Ahead Reads in STATISTICS IO: What They Tell You
Interpret read-ahead reads in STATISTICS IO, compare isolated cold scans and seeks, and separate prefetch from storage-wait evidence.
9 SQL SERVER Performance Tuning Tips – SQL in Sixty Seconds #168
This episode of SQL in Sixty seconds is very special as it contains 9 SQL SERVER Performance Tuning Tips. The length of the video is also longer.
Top Three Wait Stats and What Each One Means
The top three wait stats in the files people sent in were CXPACKET, SOS_SCHEDULER_YIELD and ASYNC_IO_COMPLETION. A small demo makes each wait happen and measures it with session wait statistics. The post explains what each one means and what to check next.
Internal Temporary Tables in MySQL: When a Query Spills to Disk
MySQL and MariaDB build internal temporary tables behind your back for GROUP BY, DISTINCT, UNION and derived tables. This post counts them with status counters, reads them in EXPLAIN, shows what pushes one to disk, and removes one with an index.
DMV Version of sp_who2: A Cleaner Session List
A DMV version of sp_who2 returns the same session details from documented views and leaves out the system tasks. This post builds the query, shows why the old spid above 50 filter fails, and stores the result in a temporary table.