Spotlight on SAP ASE 2.11 - User Guide

Direct Read and Write Rate graph

The Direct Read and Write Rate graph keeps track of reads and writes that manage large amounts of data, but do not use the selected buffer pool to do so. Instead, these reads and writes directly access the database.

The graph contains the following series, which measure the direct read and write rates over consecutive monitoring intervals. These rates are based on the number of pages read or written per second.

• Read —Plots the rate of direct reads. Direct reads are used to read VARCHAR and LOB (large object) column data from disk and to perform backups.

• Write —Plots the rate of direct writes. Direct writes are used to write VARCHAR and LOB column data to disk and to perform data loads and restores.

For related statistical information

The Statistics tab shows the direct read and write counts used to generate this graph. The names for these statistics begin with Direct. These statistics are derived from the DIRECT_READ and DIRECT_WRITE data elements that the DB2 snapshot monitor captures.