maropu commented on a change in pull request #27058: [SPARK-30276][SQL] Support Filter expression allows simultaneous use of DISTINCT URL: https://github.com/apache/spark/pull/27058#discussion_r368803416
########## File path: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/RewriteDistinctAggregates.scala ########## @@ -118,7 +118,66 @@ import org.apache.spark.sql.types.IntegerType * LocalTableScan [...] * }}} * - * The rule does the following things here: + * Third example: single distinct aggregate function with filter clauses (in sql): + * {{{ + * SELECT + * COUNT(DISTINCT cat1) FILTER (WHERE id > 1) as cat1_cnt1, + * COUNT(DISTINCT cat1) as cat1_cnt2, + * SUM(value) AS total + * FROM + * data + * GROUP BY + * key + * }}} + * + * This translates to the following (pseudo) logical plan: + * {{{ + * Aggregate( + * key = ['key] + * functions = [COUNT(DISTINCT 'cat1) with FILTER('id > 1), + * COUNT(DISTINCT 'cat1), + * sum('value)] + * output = ['key, 'cat1_cnt1, 'cat1_cnt2, 'total]) + * LocalTableScan [...] + * }}} + * + * This rule rewrites this logical plan to the following (pseudo) logical plan: + * {{{ + * Aggregate( + * key = ['key] + * functions = [count(if (('gid = 1)) '_gen_distinct_1 else null), + * count(if (('gid = 2)) '_gen_distinct_2 else null), + * first(if (('gid = 0)) 'total else null) ignore nulls] + * output = ['key, 'cat1_cnt, 'cat1_cnt2, 'total]) + * Aggregate( + * key = ['key, '_gen_distinct_1, '_gen_distinct_2, 'gid] + * functions = [sum('value)] + * output = ['key, '_gen_distinct_1, '_gen_distinct_2, 'gid, 'total]) + * Expand( + * projections = [('key, null, null, 0, 'value), + * ('key, '_gen_distinct_1, null, 1, null), + * ('key, null, '_gen_distinct_2, 2, null)] + * output = ['key, '_gen_distinct_1, '_gen_distinct_2, 'gid, 'value]) + * Expand( + * projections = [('key, if ('id > 1) 'cat1 else null, 'cat1, cast('value as bigint))] + * output = ['key, '_gen_distinct_1, '_gen_distinct_2, 'value]) + * LocalTableScan [...] + * }}} + * + * The rule serves two purposes: + * 1. Expand distinct aggregates which exists filter clause. Review comment: Not `expand distinct aggregates` but `expand data for distinct aggregates with filters`? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org