Spark: how to avoid a shuffle when joining a small table?

Joining a 2 GB fact table with a 5 MB lookup table causes a full shuffle. Any way to avoid it?

Broadcast the small side:

from pyspark.sql.functions import broadcast
facts.join(broadcast(lookup), "country_code")

Spark also does this automatically below spark.sql.autoBroadcastJoinThreshold (10 MB by default) if it knows the table size.