20.2. Connection pool properties
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20.2. Connection pool properties

Every connectionProvider class that uses a connection pool facility can manage its own connection pool properties.

The dbconnection element can configure those properties using "pool-property" child elements.

20.2.1. Protomatter ConnectionProvider supported properties

Protomatter ConnectionProvider class uses the following properties to configure its connection pool:

pool.initialSize:

The initial pool size (default is 0).

pool.maxSize:

The max pool size (default is -1). If the max pool size is -1, the pool grows infinitely.

pool.growBlock:

The grow size (default is 1). When a new object is needed, this many are created.

pool.createWaitTime:

The time (in ms) to sleep between pool object creates (default is 0).

This is useful for database connection pools where it's possible to overload the database by trying to make too many connections too quickly.

jdbc.validityCheckStatement:

A SQL statement that is guaranteed to return at least 1 row. For Oracle, this is "select 1 from dual" and for Sybase it is "select 1".

This statement is used as a means of checking that a connection is indeed working.

pool.maxConnectionIdleTime:

If this property is present, and the pool.maidThreadCheckInterval property is also present, then a thread will be created that looks for connections that have been idle for more than pool.maxConnectionIdleTime seconds. When this thread finds them, it closed the connection and logs a warning with a stack trace of when the connection was checked out of the pool.

This is primarily here as a debugging aid for finding places where connections are not getting close, and should not be used in a production environment.

pool.maidThreadCheckInterval:

This is the number of seconds between attempts by the maid thread (if present) to find idle connections.

For further details: see http://protomatter.sourceforge.net/1.1.8/javadoc/com/protomatter/jdbc/pool/JdbcConnectionPool.html

20.2.2. Protomatter ConnectionProvider configuration example

  <dbconnection
    id                      = "protomatter"
    isJndi                  = "false"
    isPow2                   = "true"
    defaultConnection       = "true"
    connectionProviderClass = "org.dbforms.conprovider.ProtomatterConnectionProvider"
    connectionPoolURL       = "jdbc:protomatter:pool:postgresPool"
    conClass                = "org.postgresql.Driver"
    name                    = "jdbc:postgresql://myHost/myDb"
    username                = "postgres"
    password                = "">
        
    <!-- jdbc properties -->
    <property name="charSet" value="ISO-8859-1" />
        
    <!-- Connection pool dataSource properties -->
    <pool-property name="pool.initialSize"             value="4"   />
    <pool-property name="pool.maxSize"                 value="10"  />
    <pool-property name="pool.growBlock"               value="2"   />
    <pool-property name="pool.createWaitTime"          value="100" />
    <pool-property name="pool.maxConnectionIdleTime"   value=""    />
    <pool-property name="pool.maidThreadCheckInterval" value=""    />
    <pool-property name="jdbc.validityCheckStatement"  value=""    />
    
  </dbconnection>

20.2.3. Jakarta ConnectionProvider supported properties

Jakarta ConnectionProvider class uses the following properties to configure its connection pool:

validationQuery:

The SQL query that will be used to validate connections from this pool before returning them to the caller. If specified, this query MUST be an SQL SELECT statement that returns at least one row.

maxActive:

The maximum number of active connections that can be allocated from this pool at the same time, or zero for no limit.

maxIdle:

The maximum number of active connections that can remain idle in the pool, without extra ones being released, or zero for no limit.

maxWait:

The maximum number of milliseconds that the pool will wait (when there are no available connections) for a connection to be returned before throwing an exception, or -1 to wait indefinitely.

For further details: http://jakarta.apache.org/commons/dbcp/api/org/apache/commons/dbcp/BasicDataSource.html

useLog: "true" | "false"

if "true", force the dataSource to log its statements using log4j.

Note: Developer added this one to activate the dataSource log.

20.2.4. Jakarta ConnectionProvider configuration example

  <dbconnection
    id                      = "jakarta-commons-dbcp"
    isJndi                  = "false"
    isPow2                  = "true"
    default                 = "false"
    connectionProviderClass = "org.dbforms.conprovider.JakartaConnectionProvider"
    connectionPoolURL       = ""
    conClass                = "org.postgresql.Driver"
    name                    = "jdbc:postgresql://localhost/myDatabase"
    username                = "postgres"
    password                = "">
            
    <!-- jdbc properties -->
    <property name="charSet" value="ISO-8859-1" />
                            
    <!-- connection pool dataSource properties -->
    <pool-property name="validationQuery" value=""     />
    <pool-property name="maxActive"       value="10"   />
    <pool-property name="maxIdle"         value="5"    />
    <pool-property name="maxWait"         value="-1"   />
    <pool-property name="useLog"          value="true" />
    
  </dbconnection>
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