TABLOCK Hint can Negatively Impact SQL Server Concurrency
In this article, we look at how using the Tablock hint in SQL Server could impact concurrency and block other sessions.
2023-11-29
Concurrency
Concurrency Challenges Around Schema Changes
A post on distributed systems and how schema changes are handled caught Steve's eye. See if you agree with how he thinks this should work.
2023-06-26
141 reads
Lock Scenarios Using sys.dm_tran_locks
Learn about the impact of locking and blocking in sessions through some demonstrations of different types of actions.
2020-06-11
8,142 reads
Concurrency Control in SQL Server
Learn a bit about concurrency problems in SQL Server, the issues they create, and the different isolation levels that help you solve them.
2020-05-12
42,497 reads
Prevent SQL Server Blocking using Lock_Timeout
In this tip we look at a way to minimize the length of blocking using SQL Server lock timeout.
2020-01-24
The Many Levels Of Concurrency
When designing for high concurrency, most people look to the hardware for answers. And while it’s true that it plays an important role, there’s a heck of a lot more to it.
2018-03-06
3,361 reads
2013-08-06
2,013 reads
Free eBook: Understanding SQL Server Concurrency
When you can’t get to your data because another application has it locked, a thorough knowledge of SQL Server concurrency will give you the confidence to decide what to do.
2020-11-11 (first published: 2013-07-17)
106,148 reads
Blogs
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Forums
Fun with JSON II
Comments posted to this topic are about the item Fun with JSON II
Changing Data Types
Comments posted to this topic are about the item Changing Data Types
Answering Questions On Dropped Columns
Comments posted to this topic are about the item Answering Questions On Dropped Columns
Question of the Day
Fun with JSON II
I have some data in a table:
CREATE TABLE #test_data
(
id INT PRIMARY KEY,
name VARCHAR(100),
birth_date DATE
);
-- Step 2: Insert rows
INSERT INTO #test_data
VALUES
(1, 'Olivia', '2025-01-05'),
(2, 'Emma', '2025-03-02'),
(3, 'Liam', '2025-11-15'),
(4, 'Noah', '2025-12-22');
If I run this query, how many rows are returned?
SELECT t1.[key] AS row,
t2.*
FROM OPENJSON(
(
SELECT t.* FROM #test_data AS t FOR JSON PATH
)
) t1
CROSS APPLY OPENJSON(t1.value) t2; See possible answers