Datasources
Datasources Datasources are databases from which the information for the entities are taken. Multiple datasources can be defined. When creating an entity, the datasource used can be defined within the property sheet, or can be dependent upon the repository from which the entity is generated.
After Xephr
Datasource properties are dependent upon the database type selected.
Datasource properties should not be modified unless absolutely necessary as it can have dire effects on the Xephr to database connections and performance.
Xephr Datasource Determination
Creating and Editing Generic ODBC Datasources
Creating and Editing IBM DB2 Datasources
Creating and Editing Microsoft Access Datasources
Creating and Editing Microsoft Excel Datasources
Creating and Editing Microsoft SQL Server Datasources
Creating and Editing Oracle 9i Datasources
Creating and Editing PostgreSQL Datasources
Creating and Editing Xephr Service Datasources
When a the Xephr system is active, database connections are made to the defined datasource. These connections are made in a connection pool that is shared by the Xephr users. The connection pool size, shrinkage, and growth is defined by the datasource properties.
When a user first logs into the Xephr system, the connection pool is created with the number of connections defined in the Initial Connections property for the datasource. As users continue to log in and use the system, existing connections are used, and when there are no more existing connections, new connections are created until the maximum number of connections is reached, defined by the Max Size property.
The maximum number of connections is either a soft limit or a hard limit, according to the setting of the Max Size Soft Limit property. If the maximum size is a soft limit, and the maximum number of connections has been met, an additional connection will be made for the user that is attempting to connect. If the maximum size is a hard limit, the new connection request will be refused until one of the existing connections is free.
Meanwhile, as users log off, the connection pool is skimmed at the rate defined by the Skimmer Frequency property. When the connection pool is skimmed, it is checked to see how many connections are actually in use. When it finds inactive connections, the number of connections closed is the lesser of the number of inactive connections and the number defined in the Shrink By property until the number of connections in the pool reaches the minimum number allowed, defined by the Min Size property.
Xephr is a registered trademark of NDS Systems, LC.
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