Cache Global Stats Test

This test gathers global activity statistics and displays a variety of information about disk I/O operations.

Target of the test : A Cache Database server

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for every InstanceName configured

Configurable parameters for the test
  1. TEST PERIOD – How often should the test be executed
  2. Host – The IP address of the Cache database server
  3. Port – The port on which the server is listening
  4. INSTANCEDIRECTORY - Typically, the Cache console log file will be available in the install directory of a Cache instance. Therefore, in the INSTANCEDIRECTORY text box, specify the name of the instance being monitored and the install directory that holds the Cache console log file of that instance, in the following format: InstanceName:InstallDirectory. In case you want to monitor the console log files pertaining to multiple Cache instances, then provide a comma-separated list of InstanceName:InstallDirectory pairs in the INSTANCEDIRECTORY text box. For example: CACHEWEB:d:\Intersystems\CacheWeb,CACHE2:d:\Intersystems\Cache2.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Global references:

Indicates the logical count of accesses to globals, including Sets, Kills, $Data, $Order, $Increment, $Query, and global references in expressions, during the last measurement period.

Number

If this number significantly jumps up or declines from the normal, there may be an application issue to research.

Global update references:

Indicates the number of calls to a routine during the last measurement period.

Number

 

Routine calls:

Indicates the current number of fatal errors on this Cache instance.

Number

 

Routine buffer loads and saves:

Indicates the total number of routine loads and saves as a result of ZLoad, ZSave, and running routines, during the last measurement period.

Number

In a well-tuned environment, this number increases slowly, since most routine loads are satisfied by the routine cache memory without accessing the disk. Each routine load or save transfers up to 32 KB of data (64 KB for Unicode).

Block I/O reads:

Indicates the number of physical database blocks (2-KB or 8-KB) read from disk during the last measurement period for both global and routine references.

Number

A high value for this measure indicates that direct disk accesses are high. In such a case your database might require some fine-tuning. Consider resizing your buffer pool to increase buffer accesses and reduce data retrievals from the disk.

Block I/O writes:

Indicates the number of physical database blocks (2-KB or 8-KB) written to disk during the last measurement period for both global and routine references.

Number

 

WIJ I/O writes:

Indicates the number of 64-KB journal blocks written to the journal file during the last measurement period.

Number

 

Logical block requests:

Indicates the number of database blocks read by the global database code during the last measurement period.

Number

In a well-tuned environment, many of these reads are satisfied without disk access.