4.1. Usage¶

This section explains how to run Replay Service from a command line. In particular, it describes:

How to Start Replay Service (Section 4.1.1).
How to Stop Replay Service (Section 4.1.2).
Replay Service command-line parameters (Section 4.1.3).

4.1.1. Starting Replay Service¶

Replay Service runs as a separate application. The script to run the executable is in <NDDSHOME>/bin. (See Section 1.3 for the path to NDDSHOME.)

rtireplayservice [options]

To start Replay Service with a default configuration, enter:

$NDDSHOME/bin/rtireplayservice

This command will run Replay Service indefinitely until you stop it.

Note

Replay Service is pre-loaded with a built-in configuration that has default settings.

4.1.2. Stopping Replay Service¶

To stop Replay Service, press Ctrl-c. Replay Service will perform a clean shutdown.

4.1.3. Replay Service Command-Line Parameters¶

The following table describes all the command-line parameters available in Replay Service. To list the available parameters, run rtireplayservice -help.

All command-line parameters are optional; if specified, they override the values of any corresponding settings in the loaded XML configuration. See Section 4.2.3 for the XML elements that can be overridden with command-line parameters.

Table 4.1 Replay Service Command-Line Parameters¶
Parameter	Description
-appName <string>	Application name used to identify this execution for remote administration, and to name the Connext DDS participant.
-cfgFile <string>	Semicolon-separated list of configuration file paths. Default: Unspecified
-cfgName	Configuration name Used to find a `<replay_service>` matching tag in the configuration file.
-domainIdBase <int>	This value is added to the domain IDs in the `<domain_participant>` tag in the configuration file. For example, if you set `-domainIdBase` to 50 and use domain IDs 0 and 1 in the configuration file, Replay Service will read domains 0 and 1 from the database, but will replay that data into domains 50 and 51. Default: 0
-D<name>=<value>	Defines a variable that can be used as an alternate replacement for XML environment variables, specified in the form $(VAR_NAME). Note that definitions in the environment take precedence over these definitions.
-help	Shows this help.
-heapSnapshotDir	Output directory where the heap monitoring snapshots are dumped. The filename format is: RTI_heap_<appName>_<processId>_<index>.log
-heapSnapshotPeriod <sec>	Period at which heap monitoring snapshots are dumped. Enables heap monitoring if > 0. Default: 0 (disabled)
-logFormat <format>	A mask to configure the format of the log messages for both Replay Service and Connext DDS. DEFAULT - Print message, method name, and activity context TIMESTAMPED - Print message, method name, activity context, and timestamp MINIMAL - Print only message number and method name MAXIMAL - Print all available fields Default: DEFAULT
-maxObjectsPerThread <int>	Maximum number of Thread-specific objects that can be created. Default: 1024.
-remoteAdministrationDomainId <int>	Enables remote administration and sets the domain ID for communication. Default: Remote administration is not enabled.
-remoteMonitoringDomainId <int>	Enables remote monitoring and sets the domain ID for status publication. Default: Remote monitoring is not enabled.
-verbosity [0-6]	RTI Service verbosity 0 - silent 1 - exceptions (Connext DDS and Replay Service) 2 - warnings (Replay Service) 3 - information (Replay Service) 4 - warnings (Connext DDS and Replay Service) 5 - tracing (Replay Service) 6 - tracing (Connext DDS and Replay Service) Default: 1 (exceptions)
-version	Prints the program version and exits.

4.1.4. Replay Service Runtime Behavior¶

Replay Service currently does not delete DataWriters, even if all original DataWriters were deleted in the recorded database.

4.1.5. Working With Large Data¶

The built-in SQLite plugin implementation available in Replay Service is prepared to handle any type size and storage format. In order to improve the fidelity of the samples published with respect to the timestamps of the original samples in the database, Replay Service internally caches the next sample to be published, so that it can be accessed more quickly when it’s time to publish. This behavior is particularly useful when replaying large data.

However, when working with large data types and massive files (or filesets), Replay Service may take a while to prepare SQL statements to work with the data, resulting in a delay in publishing the first samples for any large data topics.

Because of this delay, it is recommended that you index the user data tables for those large topics before running Replay Service on them. Indexing can massively improve Replay Service’s startup time for those topics. You can create the indexes offline, after Recording Service has finished recording all the data. Index the tables on the SampleInfo_reception_timestamp field. For example, imagine a table, VeryLargeTopic@0, has been created by Recording Service; you can use the following index creation statement:

CREATE INDEX IF NOT EXISTS [VeryLargeTopic@0_idx_rt]
        ON [VeryLargeTopic@0] (SampleInfo_reception_timestamp)