The Average Direct I/O Times graph plots the average amount of time spent performing direct reads and writes for a tablespace. These are reads and writes that directly access the tablespace and bypass the buffer pool.
The graph contains separate series for reads and writes:
Reads—Shown in light blue, this series plots the average amount of time performing direct reads for a tablespace. Direct reads are used to read VARCHAR and LOB (large object) column data from disk.
Writes—Shown in orange, this series plots the average amount of time performing direct writes for a tablespace. Direct writes are used to write VARCHAR and LOB column data to disk.
The times spent on direct reads and writes are averaged from statistics accumulated since a database was started or statistics were reset. They are shown in milliseconds on the vertical axis. Check these values along the horizontal axis to see how average times are changing over consecutive monitoring intervals of ten minutes.
Note: Check the Statistics tab to see counts for direct reads, direct writes, and requests for both.