3.10. RTI Persistence Service¶
3.10.1. External Database Compatibility¶
Previously, if you wanted to use MySQL as the external database (to use some of the durability features of Connext DDS), you needed MySQL 5.1 or higher. Now, you need MySQL 5.5 or higher.
3.10.2. Persistent Storage (Database) Format Compatibility¶
The schema of the persistent storage files and tables created by Persistence Service to store DDS samples and instances has changed. Therefore, you cannot use the files and/or tables generated with previous releases of Persistence Service with 6.0.0.
If you have this requirement, contact RTI Support at firstname.lastname@example.org.
3.10.3. Persistence Storage (Database) Locking Compatibility¶
In 5.3.0, a feature was introduced that prevents multiple Persistence Service instances from using the same database at the same time. This feature consists of a database locking mechanism, which prevents a Persistence Service instance from connecting to a database if the database is already in use by another instance.
In 5.3.0, if Persistence Service finished ungracefully, the database remained locked and required manual intervention to unlock the database.
Starting in 6.0.0, the following changes are introduced to make this feature more friendly in the ungraceful termination scenario:
- The database locking is now disabled by default. If you want to prevent
multiple instances of Persistence Service from accessing the same database,
you now need to use the command line parameter
- The database locking is renewed periodically. If the locking has not been
renewed within a certain period of time, the database will be considered
unlocked. This way, if an ungraceful termination of the service happens,
another Persistence Service instance can start and use the same database
after the previous lock expires. The locking refresh period can be controlled
with the new command-line argument (
-disableDatabaseLockingcommand-line argument has been deprecated.