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    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


    Port number

    Port number on which the agent listens

    Host name

    Name of the host on which the agent is running


    Application class to which the data point belongs


    Application instance to which the data point belongs


    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.


    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:


    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