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In case of an xUML Runtime update that modifies the database schema, you will experience a downtime for all services sharing a common database schema. A modification of the database schema will be announced in the Runtime.

Oracle

Using Oracle as a persistent state database has some advantages:

• A single xUML service can have several persistent state workers. If you use Oracle, every worker will get his own database connection.
  For other RDBMS like Microsoft SQL Server, MySQL or SQLite, all workers will use the same database connection. This means that all database operations will be serialized.
• With shared databases, Oracle has a better performance because of a better locking implementation for the persistent state use case.
  With Microsoft SQL Server, there may sometimes happen temporary deadlocks which decrease the performance.

Configuring the Persistent State Engine

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