|
Measures reported by Db2IOTest The
Db2IOTest, executed by an internal agent, tracks various statistics
pertaining to the inputs and outputs of a DB2 database. The measures
made by this test are as
follows:
| Measurement |
Description |
Measurement
Unit |
Interpretation |
| Direct_read_rate
|
Indicates the
total number of direct reads by the application per sec. In other
words, it the number of read operations that do not use the buffer
pool. |
Reads/Sec
|
Direct
reads are performed in units, the smallest being a 512-byte sector.
They are used when:
·
Reading LONG VARCHAR
columns
·
Reading LOB (large
object) columns
·
Performing a backup
A high value over a period of time may be indicative of a
performance bottleneck.
|
| Direct_write_rate
|
Indicates the
total number of direct writes by the application per sec. In other
words, it is the number of write operations that do not use the buffer
pool. |
Writes/Sec
|
Direct writes
are performed in units, the smallest being a 512-byte sector. They are
used when:
·
Writing LONG VARCHAR columns
·
Writing LOB (large object) columns
·
Performing a restore
·
Performing a load.
A high value over a period of time may be indicative of a
performance bottleneck. |
| Buffer_pool_io_rate
|
Indicates the
rate at which the buffer pool I/O operations are being done in the database. |
IOs/Sec
|
In conjunction
with the hit ratio statistics, and the characteristics of the
applications executing, the I/O load may require adjustment of
BUFFPAGE, or applications may require further tuning |
|