7.3.6. Database settings¶

The database settings define the connection parameters for connecting to the 3D City Database instance the WFS service should give access to. The contents of the <database> element are shown below.

<database>
  <connection
   initialSize="10"
   maxActive="100"
   maxIdle="50"
   minIdle="0"
   suspectTimeout="60"
   timeBetweenEvictionRunsMillis="30000"
   minEvictableIdleTimeMillis="60000">
    <description/>
    <type>PostGIS</type>
    <server/>
    <port>5432</port>
    <sid/>
    <schema/>
    <workspace/>
    <user/>
    <password/>
  </connection>
</database>

Provide the type of the database (PostGIS or Oracle), the server name (network name or IP address) and port number (default: 5432 for PostgreSQL; 1521 for Oracle) of the database server, the sid (when using PostgreSQL, enter the database name; for Oracle, enter the database SID or service name), and the user and password of the database user. You can copy&paste these settings from the config file of the Importer/Exporter. Use the optional schema element if you want to connect to a schema other than the default schema. The description is optional and can be left empty.

For Oracle databases, you can additionally specify the workspace to connect to in case your database is version-enabled. All operations will then be executed against this workspace. You must provide the <name> of the workspace and an optional <timestamp> as child elements. If no workspace is specified, the default LIVE workspace is chosen by default.

In addition to these minimum settings, the <connection> element takes optional attributes that let you configure the use of physical connections to the database server. This is especially important for production servers and if more than one WFS service connects to the same database server (in this case, you should also carefully configure the database itself). The attributes together with their meaning are described in the following table.

Table 7.4 Optional database connection settings.¶
Attribute	Description
initialSize	(int) the initial number of physical connections that are created when the database connection is established (default: 10).
maxActive	(int) The maximum number of active connections to the database that can be allocated at the same time (default: 100). NOTE – make sure your database is configured to handle this number of parallel active connections.
maxIdle	(int) The maximum number of connections that should be kept active at all times (default: 50). Idle connections are checked periodically (if enabled) and connections that have been idle for longer than minEvictableIdleTimeMillis will be released. (also see testWhileIdle)
minIdle	(int) The minimum number of established connections that should be kept active at all times (default: 0). The connection pool can shrink below this number if validation queries fail.
maxWait	(int) The maximum number of milliseconds that the service will wait (when there are no available connections) for a connection before throwing an exception (default: 30000, i.e. 30 seconds).
testOnBorrow	(boolean) The indication of whether connections will be validated before being used by the service. If the connections fails to validate, it will be dropped, and the service will attempt to borrow another (default: false). NOTE - for a true value to have any effect, the validationQuery parameter must be set to a non-null string. In order to have a more efficient validation, see validationInterval.
testOnReturn	(boolean) The indication of whether connections will be validated before being returned to the internal connection pool (default: false). NOTE - for a true value to have any effect, the validationQuery parameter must be set to a non-null string.
testWhileIdle	(boolean) The indication of whether connections will be validated by the idle connections evictor (if any). If a connections fails to validate, it will be dropped (default: false). NOTE - for a true value to have any effect, the validationQuery parameter must be set to a non-null string.
validationQuery	(String) The SQL query that will be used to validate connections. If specified, this query does not have to return any data (default: null). Example values are “select 1 from dual” (Oracle) or “select 1” (PostgreSQL).
validationClassName	(String) The name of a class which implements the org.apache.tomcat.jdbc.pool.Validator interface and provides a no-arg constructor (may be implicit). If specified, the class will be used to instead of any validation query to validate connections (default: null). NOTE – for a non-null value to have any effect, the class has to be implemented by you as part of the source code of the WFS service. Use with care.
timeBetweenEvictionRunsMillis	(int) The number of milliseconds to sleep between runs of the idle connection validation/cleaner. This value should not be set under 1 second. It dictates how often we check for idle, abandoned connections, and how often we validate idle connections (default: 30000, i.e. 30 seconds).
minEvictableIdleTimeMillis	(int) The minimum amount of time a connection may be idle before it is eligible for eviction (default: 60000, i.e. 60 seconds).
removeAbandoned	(boolean) Flag to remove abandoned connections if they exceed the removeAbandonedTimout. If set to true a connection is considered abandoned and eligible for removal if it has been in use longer than the removeAbandonedTimeout See also logAbandoned (default: false).
removeAbandonedTimeout	(int) Timeout in seconds before an abandoned (in use) connection can be removed (default: 60, i.e. 60 seconds). The value should be set to the longest running query.
logAbandoned	(boolean) Flag to log stack traces for application code which abandoned a connection. NOTE - this adds overhead for every connection borrow (default: false).
connectionProperties	(String) The connection properties that will be sent to the JDBC driver when establishing new connections. Format of the string must be [propertyName=property;]* NOTE - The “user” and “password” properties will be passed explicitly, so they do not need to be included here (default: null).
initSQL	(String) A custom query to be run when a connection is first created (default: null).
validationInterval	(long) To avoid excess validation, only run validation at most at this frequency - time in milliseconds. If a connection is due for validation, but has been validated previously within this interval, it will not be validated again (default: 30000, i.e. 30 seconds).
jmxEnabled	(boolean) Register the internal connection pool with JMX or not (default: true).
fairQueue	(boolean) Set to true if connection requests should be treated fairly in a true FIFO fashion (default: true)
abandonWhenPercentageFull	(int) Connections that have been abandoned (timed out) will not get closed and reported up unless the number of connections in use are above the percentage defined by abandonWhenPercentageFull. The value should be between 0-100 (default: 0, which implies that connections are eligible for closure as soon as removeAbandonedTimeout has been reached).
maxAge	(long) Time in milliseconds to keep connections alive. When a connection is returned to the internal pool, it will be checked whether now - time-when-connected > maxAge has been reached, and if so, the connection is closed (default: 0, which implies that connections will be left open and no age check will be done).
suspectTimeout	(int) Timeout value in seconds (default: 0).