For free text metadata, stores the indexed keywords. Fixed list indexing is stored separately via resource_node and node_keyword.
resource,int(11),
keyword,int(11),
hit_count,int(11),The live hitcount. This value is copied from the new_hit_count column. See copy_hitcount_to_live()
position,int(11),The position of the keyword in the indexed string for advanced searching.
resource_type_field,int(11),
new_hit_count,int(11),For each matching keyword in a search, the new hitcount is incremented so existing results are not affected. See update_resource_keyword_hitcount()