To determine if a query is too large to fit in memory, you need to look for indications that data is being spilled to storage. 'Bytes spilled to local cache' typically refers to data that does not fit in memory and is temporarily being stored in a cache. 'Bytes spilled to local storage' indicates that data is being written to local disk because it cannot be held in memory. Both of these statistics are strong indicators that the query is exceeding the available memory.