| Measurement |
Description |
Measurement
Unit |
Interpretation |
| Read_cache_hit_ratio |
The ratio of number of buffer reads to disk reads |
Percent
|
This measure is an indicator of the overall performance of your database server. This value should always be high. |
| Write_cache_hit_ratio |
The ratio of number of buffer writes to disk writes
|
Percent
|
This measure is an indicator of the overall performance of your database server. This value should always be high.
|
| Flushes |
The rate at which buffer-pool buffers were flushed to disk
|
Flushes/Sec
|
|
| Foreground_writes |
The number of foreground writes per second during the last measurement period
|
Writes/Sec
|
Foreground writes should be avoided. They slow down the performance of your database server. If you find that foreground writes are occurring on a regular basis, tune the value of the page-cleaning parameters. Either increase the number of page cleaners or decrease the value of LRU_MAX_DIRTY.
|
| LRU_writes |
The number of LRU writes per second during the last measuremnet period
|
Writes/Sec
|
Compare this value with Foreground_writes and Chunk_writes to get an understanding of how the buffer flushing occurs in Informix.
|
| Chunk_writes |
The number of chunk writes per second during the last measurement period
|
Writes/Sec
|
Chunk writes are commonly performed by page-cleaner threads during a checkpoint or, possibly, when every page in the shared-memory buffer pool
is modified. Chunk writes, which are performed as sorted writes, are the most efficient writes available to the database server.
Compare this value with Foreground_writes and LRU writes to get an understanding of how the buffer flushing occurs in Informix.
|