The R/s dataflow depicts the rate at which prefetchers are reading data and index pages from the database or partition into buffer pools. Prefetchers read specific pages into buffer pools, anticipating an application’s need for these pages. These reads are asynchronous because they are not part of the processing of program instructions¾and therefore can run in parallel with database agent processes.
At each refresh, Spotlight captures the following statistic and displays it just above the read rate dataflow:
R/s (asynchronous read rate)—The number of asynchronous reads per second at the database or partition level.
The line graph that overlays the dataflow plots the asynchronous read rate captured over the series of refreshes that have occurred during the Spotlight session.
Click the R/s dataflow to open the Databases drilldown. This drilldown provides details about the database or partition that you are currently monitoring. The I/O Activity tab on the drilldown is in immediate focus to help you pinpoint I/O flow problems in the database or partition.