What Write Ahead Logging Is and Why It Matters
Kendra Little talks about write ahead logging in SQL Server, one of the basic concepts that developers and DBAs should understand.
2024-06-12 (first published: 2020-01-20)
4,778 reads
Transaction Log
2019-08-27
896 reads
How to read the SQL Server Database Transaction Log
In this tip we will take a look at a SQL Server function that you can use to read the SQL Server transaction log to see what entries are made for database transactions.
2019-07-05
How Big is Your Transaction Log?
If you are not managing the transaction log space used by a database, the transaction log might grow uncontrollably. With SQL Server 2017 there is a new dynamic management function (DMF) that exposes statistical information about a database transaction log. One of the things you can do with the information returned from this DMF is to determine how full a database transaction log file is.
2018-11-06
3,724 reads
How to determine SQL Server database transaction log usage
One crucial aspect of all databases is the transaction log. The transaction log is used to write all transactions prior to committing the data to the data file. In some circumstances the transaction logs can get quite large and not knowing what is in the transaction log or how much space is being used can become a problem. So how to you determine how much of the transaction log is being used and what portions are being used?
2017-10-24
4,163 reads
How to Read a Transaction Log Backup
The transaction log backup is stored in SQL Server proprietary format, just like the transaction log itself. Even though the transaction log backup is in a special format, Microsoft has provided us with the fn_dump_dblog() function to read transaction log backups. This function is undocumented, so you should use care when using this function in a production environment.
2017-08-17
4,324 reads
How to Read the Transaction Log File
Have you ever wanted to be able to see the actual transactions that are contained in the transaction log file? Greg Larsen shows you how to browse the transaction log using an undocumented function.
2017-07-26
5,228 reads
How to Read the Transaction Log File
Have you ever wanted to be able to see the actual transactions that are contained in the transaction log file? Greg Larsen shows you how to browse the transaction log using an undocumented function.
2017-06-27
4,882 reads
How to read the SQL Server Database Transaction Log
Manvendra Singh takes a look at a SQL Server function that you can use to read the transaction log to see what entries are made for database transactions.
2016-12-30
4,902 reads
2016-06-21
1,309 reads
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Fun with JSON II
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Changing Data Types
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Answering Questions On Dropped Columns
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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