Currently i2b2 1.7 uses the following validations for its default installations which are not ideal.

<validation>
    <validate-on-match>false</validate-on-match>
    <background-validation>false</background-validation>
</validation>

If we encounter a situation in which a connection in the pool goes bad we will continue to use that connection which will cause errors in i2b2. The better solution would be to use validation.

<validation>
    <validate-on-match>true</validate-on-match>
    <check-valid-connection-sql>SELECT 1 FROM DUAL</check-valid-connection-sql>
    <use-fast-fail>true</use-fast-fail>
</validation>

Obviously the sql will change per database engine but it should be easy to configure based on each of the datasources defined ie "SELECT 1" for MSSQL