Overview of PATROL history

The PATROL Agent records the values of each parameter and stores them in a proprietary parameter history database. This database remains open while the agent is running. If the agent does not shut down properly, the database may be corrupted. PATROL provides a utility that enables you to extract information from the database about a parameter based on its class, instance, and time period. It also provides a utility for repairing corrupted history databases.

Contents of PATROL Agent history database

The PATROL Agent History database records the following information for each data point:

Information stored in history database

Information type	Description
Port number	Port number on which the agent listens
Host name	Name of the host on which the agent is running
Class	Application class to which the data point belongs
Instance	Application instance to which the data point belongs
Parameter	Parameter to which the data point belongs
Time and date	Time and date on which the data point was collected
Annotated text (if provided)	Descriptive text associated with the data point

Structure of PATROL Agent history datase

PATROL stores history information in a history database that consists of three separate files as follows:

Index file: points to the location of the data in the database
History text file: contains annotations that a user has added to a data point
History data file: contains data points

The history database stores information in a binary format. To view the information, you must use the PATROL Console or run the dump_hist utility.

Note

PATROL Agent does not support history files of size larger than 2 GB on any platform.

Location of PATROL Agent history database

The PATROL Agent provides environment variables that enable you to determine where the agent creates the history database. You can designate a location in or out of the PATROL directory structure or on another host within the network. In addition, you can establish a location by port number. This feature allows you to accommodate a host with multiple agents by directing each agent running on a unique port number to write to a different history database.

Custom location of PATROL Agent history database

The environment variables that you can use to specify the location of an Agent's history database are as follows:

PATROL_HISTORY
PATROL_HISTORY_<PORT>
PATROL_VIRTUALNAME

For information about how to use these environment variables, see variables for PATROL cluster-specific environment.

Default location of PATROL Agent history database

The following table indicates the file name and path of files that compose the history database.

Location of history files

File description	File name and path for UNIX
	File name and path for Windows
Index file	PATROL_HOME/log/history/<hostName> / <port_num>/dir
	PATROL_HOME\log\history\<hostName> \ <port_num>\dir
History text file	PATROL_HOME/log/history/<hostName> / <port_num>/param.hist
	PATROL_HOME\log\history\<hostName> \ <port_num>\param.hist
History data file	PATROL_HOME/log/history/<hostName> / <port_num>/annotate.dat
	PATROL_HOME\log\history\<hostName> \ <port_num>\annotate.dat