Guru Guide To Sql Server Architecture And Internals.pdf Online

SELECT * FROM sys.dm_os_buffer_descriptors WHERE database_id = DB_ID('SalesDB'); He saw that 40 GB of the buffer pool was filled with old data from a morning report. The ETL’s needed pages (the clustered index of Orders ) were being paged in from disk— couldn’t save it because the scan had already caused random I/O earlier.

SELECT name, log_reuse_wait_desc FROM sys.databases WHERE name = 'SalesDB'; Result: LOG_BACKUP . Wait—backups were running fine. But why?

Alex updated stats:

He ran:

The transaction log is a circular log. It can’t reuse space if any active transaction holds onto a VLFL (virtual log file) even if it’s old. Guru Guide To Sql Server Architecture And Internals.pdf

I can’t directly open or read the contents of a specific PDF file like Guru Guide To SQL Server Architecture And Internals.pdf . However, I can give you a based on the typical themes found in that book—focusing on SQL Server’s core architecture (query processor, storage engine, buffer pool, transaction log, and locking).

He looked at sys.dm_tran_database_transactions during the ETL. One transaction had an old database_transaction_begin_time from 3 hours ago—an open transaction from a developer’s BEGIN TRAN in SSMS that was never committed or rolled back. SELECT * FROM sys

That open transaction was preventing the transaction log from truncating. The log had grown to 200 GB. The ETL’s large update inside FactSales_Load had to wait for log space, causing log autogrowth events (zero-initialization → slow).