A query within the correlate() function that defines the pattern required for a constellation to exist. All mandatory queries must match events for LogScale to identify a constellation. Mandatory queries establish the core pattern that LogScale searches for—for example, a login event followed by a purchase event from the same user. If any mandatory query in the pattern does not find a match, no constellation is created. Mandatory queries are distinct from aggregation queries, which enrich existing constellations but do not affect whether constellations are found.