PREHOOK: query: CREATE TABLE T1(key STRING, val STRING) SKEWED BY (key, val) ON ((2, 12), (8, 18)) STORED AS TEXTFILE PREHOOK: type: CREATETABLE PREHOOK: Output: database:default PREHOOK: Output: default@T1 POSTHOOK: query: CREATE TABLE T1(key STRING, val STRING) SKEWED BY (key, val) ON ((2, 12), (8, 18)) STORED AS TEXTFILE POSTHOOK: type: CREATETABLE POSTHOOK: Output: database:default POSTHOOK: Output: default@T1 PREHOOK: query: LOAD DATA LOCAL INPATH '../../data/files/T1.txt' INTO TABLE T1 PREHOOK: type: LOAD #### A masked pattern was here #### PREHOOK: Output: default@t1 POSTHOOK: query: LOAD DATA LOCAL INPATH '../../data/files/T1.txt' INTO TABLE T1 POSTHOOK: type: LOAD #### A masked pattern was here #### POSTHOOK: Output: default@t1 PREHOOK: query: CREATE TABLE T2(key STRING, val STRING) SKEWED BY (key, val) ON ((3, 13), (8, 18)) STORED AS TEXTFILE PREHOOK: type: CREATETABLE PREHOOK: Output: database:default PREHOOK: Output: default@T2 POSTHOOK: query: CREATE TABLE T2(key STRING, val STRING) SKEWED BY (key, val) ON ((3, 13), (8, 18)) STORED AS TEXTFILE POSTHOOK: type: CREATETABLE POSTHOOK: Output: database:default POSTHOOK: Output: default@T2 PREHOOK: query: LOAD DATA LOCAL INPATH '../../data/files/T2.txt' INTO TABLE T2 PREHOOK: type: LOAD #### A masked pattern was here #### PREHOOK: Output: default@t2 POSTHOOK: query: LOAD DATA LOCAL INPATH '../../data/files/T2.txt' INTO TABLE T2 POSTHOOK: type: LOAD #### A masked pattern was here #### POSTHOOK: Output: default@t2 PREHOOK: query: -- Both the join tables are skewed by 2 keys, and one of the skewed values -- is common to both the tables. The join key matches the skewed key set. -- adding a order by at the end to make the results deterministic EXPLAIN SELECT a.*, b.* FROM T1 a JOIN T2 b ON a.key = b.key and a.val = b.val PREHOOK: type: QUERY POSTHOOK: query: -- Both the join tables are skewed by 2 keys, and one of the skewed values -- is common to both the tables. The join key matches the skewed key set. -- adding a order by at the end to make the results deterministic EXPLAIN SELECT a.*, b.* FROM T1 a JOIN T2 b ON a.key = b.key and a.val = b.val POSTHOOK: type: QUERY STAGE DEPENDENCIES: Stage-1 is a root stage Stage-2 depends on stages: Stage-1, Stage-4 Stage-4 is a root stage Stage-0 depends on stages: Stage-2 STAGE PLANS: Stage: Stage-1 Map Reduce Map Operator Tree: TableScan alias: a Statistics: Num rows: 0 Data size: 30 Basic stats: PARTIAL Column stats: NONE Filter Operator predicate: ((key is not null and val is not null) and ((((key = '2') and (val = '12')) or ((key = '8') and (val = '18'))) or ((key = '3') and (val = '13')))) (type: boolean) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Reduce Output Operator key expressions: key (type: string), val (type: string) sort order: ++ Map-reduce partition columns: key (type: string), val (type: string) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE TableScan alias: b Statistics: Num rows: 0 Data size: 30 Basic stats: PARTIAL Column stats: NONE Filter Operator predicate: ((key is not null and val is not null) and ((((key = '2') and (val = '12')) or ((key = '8') and (val = '18'))) or ((key = '3') and (val = '13')))) (type: boolean) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Reduce Output Operator key expressions: key (type: string), val (type: string) sort order: ++ Map-reduce partition columns: key (type: string), val (type: string) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Reduce Operator Tree: Join Operator condition map: Inner Join 0 to 1 keys: 0 key (type: string), val (type: string) 1 key (type: string), val (type: string) outputColumnNames: _col0, _col1, _col5, _col6 Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Select Operator expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string) outputColumnNames: _col0, _col1, _col2, _col3 Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE File Output Operator compressed: false table: input format: org.apache.hadoop.mapred.SequenceFileInputFormat output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe Stage: Stage-2 Map Reduce Map Operator Tree: TableScan Union Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE File Output Operator compressed: false Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE table: input format: org.apache.hadoop.mapred.TextInputFormat output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe TableScan Union Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE File Output Operator compressed: false Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE table: input format: org.apache.hadoop.mapred.TextInputFormat output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe Stage: Stage-4 Map Reduce Map Operator Tree: TableScan alias: a Statistics: Num rows: 0 Data size: 30 Basic stats: PARTIAL Column stats: NONE Filter Operator predicate: ((key is not null and val is not null) and (not ((((key = '2') and (val = '12')) or ((key = '8') and (val = '18'))) or ((key = '3') and (val = '13'))))) (type: boolean) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Reduce Output Operator key expressions: key (type: string), val (type: string) sort order: ++ Map-reduce partition columns: key (type: string), val (type: string) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE TableScan alias: b Statistics: Num rows: 0 Data size: 30 Basic stats: PARTIAL Column stats: NONE Filter Operator predicate: ((key is not null and val is not null) and (not ((((key = '2') and (val = '12')) or ((key = '8') and (val = '18'))) or ((key = '3') and (val = '13'))))) (type: boolean) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Reduce Output Operator key expressions: key (type: string), val (type: string) sort order: ++ Map-reduce partition columns: key (type: string), val (type: string) Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Reduce Operator Tree: Join Operator condition map: Inner Join 0 to 1 outputColumnNames: _col0, _col1, _col5, _col6 Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE Select Operator expressions: _col0 (type: string), _col1 (type: string), _col5 (type: string), _col6 (type: string) outputColumnNames: _col0, _col1, _col2, _col3 Statistics: Num rows: 0 Data size: 0 Basic stats: NONE Column stats: NONE File Output Operator compressed: false table: input format: org.apache.hadoop.mapred.SequenceFileInputFormat output format: org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat serde: org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe Stage: Stage-0 Fetch Operator limit: -1 Processor Tree: ListSink PREHOOK: query: SELECT a.*, b.* FROM T1 a JOIN T2 b ON a.key = b.key and a.val = b.val ORDER BY a.key, b.key, a.val, b.val PREHOOK: type: QUERY PREHOOK: Input: default@t1 PREHOOK: Input: default@t2 #### A masked pattern was here #### POSTHOOK: query: SELECT a.*, b.* FROM T1 a JOIN T2 b ON a.key = b.key and a.val = b.val ORDER BY a.key, b.key, a.val, b.val POSTHOOK: type: QUERY POSTHOOK: Input: default@t1 POSTHOOK: Input: default@t2 #### A masked pattern was here #### 3 13 3 13 8 18 8 18 8 18 8 18