To find the OS thread of a session, join sys.dm_os_tasks to sys.dm_os_threads on the worker address. This post reads the map for your own session and for every user session. It explains why idle sessions have no row, why parallel queries have several, and how to follow a thread in Performance Monitor.
SQL Server emergency? Email pinal@sqlauthority.com with URGENT in the subject line.
sys.dm_exec_valid_use_hints: Every USE HINT Your Server Knows
sys.dm_exec_valid_use_hints lists every USE HINT name that your SQL Server accepts. This post groups the 35 names on SQL Server 2025 and shows the compile error for a misspelled hint. It applies two hints and reads the plan to prove each one worked, then compares USE HINT with QUERYTRACEON.
JDBC and sendStringParametersAsUnicode: The Hidden Index Scan
Diagnose sendStringParametersAsUnicode conversions, align JDBC parameters with varchar indexes, and preserve required Unicode data.
SQL Puzzle – SELECT ~ 1 : Guess the Answer
SELECT ~ 1 returns -2 because the tilde is the bitwise NOT operator and flips all 32 bits of an int. This post keeps the puzzle, tests the answer on SQL Server 2025 with five data types and shows where the tilde is useful.
NOT IN With a NULL in the List Returns No Rows
See why NOT IN with a NULL returns no customers, then compare five sample rows, NOT EXISTS, an IS NOT NULL filter, and query plans.
Threads With Zero Rows in a Parallel Plan, Measured
A parallel plan can show threads with zero rows, and that is normal. This post reads the per-thread row counters of two real plans on SQL Server 2025 and shows where the empty threads come from. It also says when an empty thread points to a real problem.
Azure SQL Database Serverless: Auto-Pause and What Wakes It
Understand Azure SQL Database serverless limits, auto-pause, resume delays, and billing metrics before choosing an idle strategy.
SQL Server slow? Let's fix it together in about four hours.
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Who We Are
Pinal Dave is an SQL Server Performance Tuning Expert and independent consultant with over 24 years of hands-on experience. He holds a Masters of Science degree and numerous database certifications.
Pinal has authored 19 books and 125 Pluralsight courses. To freely share his knowledge and help others build their expertise, Pinal has also written more than 5,800 database tech articles on his blog at https://blog.sqlauthority.com.
Pinal is also a CrossFit Level 1 Trainer (CF-L1) and CrossFit Level 2 Trainer (CF-L2).
Nupur Dave is a social media enthusiast and an independent consultant. She primarily focuses on the database domain, helping clients build short and long-term multi-channel campaigns to drive leads for their sales pipeline.
Shaivi Pinalkumar Dave is a book author and a women’s artistic gymnast.

