Informix Buffers Test
This test reports statistics pertaining to the caching and buffer flushing activities of the Informix database server.
Target of the test : An Informix Dynamic server
Agent deploying the test : An internal agent
Outputs of the test : One set of results for the Informix server being monitored.
Parameters | Description |
---|---|
Test Period |
This indicates how often should the test be executed. |
Host |
The IP address of the Informix Dynamic server. |
Port |
The port number at which the specified host listens to. |
Instance |
The Informix server instance being monitored. |
DB |
Specify the name of a database on the server. |
User |
A valid Informix user name to login to the specified database. |
Password |
The password corresponding to the above user. |
Confirm Password |
Confirm the Password by retyping it here. |
DBLocale |
Specify the language/locale in which your database is installed. This will allow you to return the query in the language supported by your database. By default this attribute is set to “none”, which means that by default, queries are returned in the English locale. |
ClientLocale |
Specify the language/locale in which the eG agent is running. Normally, when you use an internal agent to monitor Informix, the ClientLocale and DBLocale will be same. However, the ClientLocale may differ when you are monitoring the Informix tests using a remote agent (agentless monitoring). By default, the ClientLocale is set to “none”, indicating that the eG agent runs in the English locale, by default. |
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 measurement 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. |