so I checked the source code. the value seems that should be in fact 7. current default value means 1.6 thousand millenniums .
<property> <name>crawl.gen.delay</name> <value>604800000</value> <description> This value, expressed in days, defines how long we should keep the lock on records in CrawlDb that were just selected for fetching. If these records are not updated in the meantime, the lock is canceled, i.e. the become eligible for selecting. Default value of this is 7 days. </description> </property>
