Guru Guide To Sql Server Architecture And Internals.pdf May 2026

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).

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

The buffer pool is a shared resource. Morning report’s KEEP hints or large scans polluted the cache. That open transaction was preventing the transaction log