you can modify solrcore.properties configuration file and edit "alfresco.cron" property. "alfresco.cron" property specifies the cron expression that instructs Solr how often to track Alfresco and index new or updated content. The default valuis is 15 seconds. Why do you want to change indexing frequence from daily to weekly ? it may cause many new created(updated) nodes can't be searched.
in the index.tracking.cronExpression=0,00,19 * * * * ? entry in repository.properties file. The solr index will be executed every day at 7:00pm the pb is that this index solr use a huge precent of CPU, and it's cause pb to other applications like bonita … so i've think that indexing solr weekly can be a good solution. But i am OK with you when you say that this modification can cause pb in new created(updated) nodes. thank you