DIH close database connection directly after entity is completed

I use DIH to create an index for a number of postgres databases. These databases all contain an identical schema/table setup. The config looks like <entity rootEntity="false"><entity/><entity/></entity> repeated for each datasource. The readonly flag is set to true on the subentity objects. For each database solr creates three connections. These connections remain active as "idle in transaction" until the indexer is finished. As the number of databases times three exceeds my max_connections setting in postgres the indexer inevitably fails halfway through with a no more connections available error.