org.apache.spark.sql.aliyun.redis
refer to org.apache.spark.sql.redis.RedisSourceRelation and change org.apache.spark.sql.redis.RedisSourceRelation.dataKeyId() for idempotent write
true if data exists in redis
true if no data exists in redis
refer to org.apache.spark.sql.redis.RedisSourceRelation and change org.apache.spark.sql.redis.RedisSourceRelation.dataKeyId() for idempotent write