Crawler parameters define the behavior of a crawler. Crawlers help to update indexes.
A schedule defines one or more time intervals at which the crawler is started.
You can select crawler parameters and schedules in the following places in index administration.
Properties screen
You can define default entries for crawler parameters and schedules in this screen. These default entries are valid for all data sources for which you make no other settings.
Data Sources screen
You can select crawler parameters for individual data sources and define schedules in this screen. The settings for an individual data source override default entries.
You can set the crawler parameters and schedule independently of each other. For example, you can override the default entry for the crawler parameters in a data source but still use the default entry for the schedule.