The Direct Read and Write Rate graph keeps track of direct reads and writes on the tablespace—that is, reads and writes that do not involve the buffer pool, but directly access the tablespace to manage large amounts of data and to perform utility functions.
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 per second.
Direct reads —Plots the rate of direct reads on the tablespace. Direct reads are used to read VARCHAR and LOB (large object) column data from disk and to perform backups.
Direct writes —Plots the rate of direct writes on the tablespace. Direct writes are used to write VARCHAR and LOB column data to disk and to perform data loads and restores.
The Statistics tab shows the direct read and write counts used to generate this graph. The names for these statistics begin with Direct.