September 2010
Intermediate to advanced
1704 pages
111h 8m
English
In the preceding section, we looked at monitoring overall disk activity. In this section, we examine what SQL Server’s contribution is to all this disk activity. Disk activity can be categorized into reads and writes. SQL Server carries out writes to the disk for the following processes:
• Logging records
• Writing dirty cache pages at the end of a transaction
• Freeing space in the page cache
Logging is a constant occurrence in any database that allows modifications, and SQL Server attempts to optimize this process by batching a number of writes together. To see how much work is done on behalf of the database logs, you can examine the SQLServer:Databases:Log Bytes Flushed and SQLServer:Databases:Log Flushes/sec ...