SQL batches

The number of Transact SQL command batches received by SQL Server. For the SAP R/3 work processes, a batch is created every time a database commit is required. This number is usually much smaller than the number of database requests issued by ABAP.

Read ahead pages

The number of requests that are read ahead, that is, asynchronously prefetched from disk.

Request buffer pages

The total number of requests for buffer pages, or data cache pages, issued by SQL Server. This is a logical request, so if the page exists in the cache, no physical read/write takes place. If the page is not in cache, then a physical page read will be recorded.

reads

The number of physical page reads into the data cache. The total number of pages, across all databases, is recorded.

writes

The number of physical page writes from the data cache. This is the total number of pages written across all databases.

Full table/index scans

The number of full table or index scans. These scans can be either base-table or full-index scans.

Index range scans

The number of qualified range scans through indexes. This number represents logical, as opposed to physical, access.

Index searches

The number of index searches. Index searches are used to start range scans and single index record fetches.

Probe scans

The number of probe scans that occur in a database. Probe scans are used to find rows in an index or base table directly.

Lazy write

The number of buffers written by the buffer manager's Lazy Writer. The Lazy Writer is a system process whose task is to write dirty buffers to disk when I/O activity is low. The goal of the Lazy Writer is to minimize the time needed by checkpoints to write dirty data pages to disk.