Database connectivity

The Spotfire Server database connection pool implementation is used for two things: connecting to the Spotfire database and connecting to JDBC compliant data sources through Information Services.

Each connection pool (either for Spotfire Server itself or for fetching data) has many parameters; the following are of general interest:

The driver-class parameter contains the JDBC driver class name; see Database drivers and database connection URLs.
The url parameter contains the JDBC connection URL; see Database drivers and database connection URLs.
The username parameter contains the name of the database user to connect as, if applicable.
The password parameter contains the password for the specified database user, if applicable. The password is always encrypted and must therefore be set using the bootstrap command. It cannot be set manually.
The min-connections parameter contains the minimum number of allocated connections.
The max-connections parameter contains the maximum number of allocated connections. Depending on the pooling scheme, the total number of connections created by the server may be higher than the value of this parameter during high load, but all such extra connections will automatically be closed when the load decreases. By setting this parameter to zero or a negative value, connection pooling is effectively disabled and new connections will be continuously created as needed.
The pooling-scheme parameter defines the connection pooling algorithm to be used. There are two possible connection pooling algorithms that determine the way the connection pool operates, "DYNAMIC" and "WAIT". The "WAIT" algorithm is the default.
When initialized, the connection pool creates a number of idle database connections equal to the min-connections parameter. When the connection pool receives a request for a database connection, it checks if the pool contains any idle connections and uses one of those, if available.
- The "DYNAMIC" pooling scheme—If there are no idle connections in the pool, it automatically creates a new database connection. There is no upper limit for how many connections a connection pool can have open at the same time.
- The "WAIT" pooling scheme—If there are no idle connections in the pool and the number of already open connections is less than the max-connections parameter, it creates a new database connection.
  If the number of already open connections is equal to the max-connections parameter, it waits for an active connection to be returned to the pool. If the request cannot be fulfilled within a number of seconds equal to the login-timeout parameter, the request times out. In the server logs entries similar to this appear, "Timeout while waiting for database connection after 10 seconds".
  
  Thus, in WAIT mode, the connection pool can never have more open (active or idle) connections than the value of the max-connections parameter. Whenever a database connection is returned, it is put in the pool of idle connections, unless it is used immediately to fulfill an already waiting request.

Idle connections in the database connection pool eventually time out if they are not used. The connection-timeout parameter defines how long (in seconds) a connection can remain idle in the connection pool before being closed and discarded.