How to properly do conditional aggregation in Hive










1















Assume I have this data:



player_id stats
100 ["position":"offense","wins":35,"position":"defense","wins":17]
200 ["position":"offense","wins":85,"position":"defense","wins":52]
300 ["position":"offense","wins":12,"position":"defense","wins":98]


And I want to display it as such:



player_id offense_wins defense_wins
100 35 17
200 85 52
300 12 98


The original data above is currently thrown into an ORC table using:



SELECT p.player_id
, s.position
, s.wins
FROM player_stats p
LATERAL VIEW EXPLODE(p.stats) sTable as s


Which gets me:



player_id position wins
100 offense 35
100 defense 17
200 offense 85
200 defense 52
300 offense 12
300 defense 98


Now from this point in MySQL I can just group_by the player_id then case the position, pulling in the associated wins value when it = 'offense' or 'defense' into their own columns, then wrap each case in a COALESCE() to prevent the nulls from coming through. Super fast.



In Hive, instead of COALESCE I have to use MIN or MAX, but the result will be the same regardless.



Here would be the primary way this data is queried:



SELECT player_id
, max(case when position = 'offense' then wins end) as offense_wins
, max(case when position = 'defense' then wins end) as defense_wins
FROM orctable
WHERE player_id = 100
GROUP BY player_id


Which would result in :



player_id offense_wins defense_wins
100 35 17


Now, in my real world situation the original dataset has six instances of that 'stats' array, each containing a map of 3-5 pairs. Because of this, the ORC table has player_id listed some 700 times from the repeated lateral views.



The entire table is 300k rows, and the player_id in the real world example is duplicated on this table just over 700 times.



Question 1 - is this the only and/or proper way to transform the data into the desired end result?
Question 2 - should this query be taking between 5 and 10 seconds to complete? The same dataset on a small MySQL server would do this in milliseconds.










share|improve this question


























    1















    Assume I have this data:



    player_id stats
    100 ["position":"offense","wins":35,"position":"defense","wins":17]
    200 ["position":"offense","wins":85,"position":"defense","wins":52]
    300 ["position":"offense","wins":12,"position":"defense","wins":98]


    And I want to display it as such:



    player_id offense_wins defense_wins
    100 35 17
    200 85 52
    300 12 98


    The original data above is currently thrown into an ORC table using:



    SELECT p.player_id
    , s.position
    , s.wins
    FROM player_stats p
    LATERAL VIEW EXPLODE(p.stats) sTable as s


    Which gets me:



    player_id position wins
    100 offense 35
    100 defense 17
    200 offense 85
    200 defense 52
    300 offense 12
    300 defense 98


    Now from this point in MySQL I can just group_by the player_id then case the position, pulling in the associated wins value when it = 'offense' or 'defense' into their own columns, then wrap each case in a COALESCE() to prevent the nulls from coming through. Super fast.



    In Hive, instead of COALESCE I have to use MIN or MAX, but the result will be the same regardless.



    Here would be the primary way this data is queried:



    SELECT player_id
    , max(case when position = 'offense' then wins end) as offense_wins
    , max(case when position = 'defense' then wins end) as defense_wins
    FROM orctable
    WHERE player_id = 100
    GROUP BY player_id


    Which would result in :



    player_id offense_wins defense_wins
    100 35 17


    Now, in my real world situation the original dataset has six instances of that 'stats' array, each containing a map of 3-5 pairs. Because of this, the ORC table has player_id listed some 700 times from the repeated lateral views.



    The entire table is 300k rows, and the player_id in the real world example is duplicated on this table just over 700 times.



    Question 1 - is this the only and/or proper way to transform the data into the desired end result?
    Question 2 - should this query be taking between 5 and 10 seconds to complete? The same dataset on a small MySQL server would do this in milliseconds.










    share|improve this question
























      1












      1








      1


      0






      Assume I have this data:



      player_id stats
      100 ["position":"offense","wins":35,"position":"defense","wins":17]
      200 ["position":"offense","wins":85,"position":"defense","wins":52]
      300 ["position":"offense","wins":12,"position":"defense","wins":98]


      And I want to display it as such:



      player_id offense_wins defense_wins
      100 35 17
      200 85 52
      300 12 98


      The original data above is currently thrown into an ORC table using:



      SELECT p.player_id
      , s.position
      , s.wins
      FROM player_stats p
      LATERAL VIEW EXPLODE(p.stats) sTable as s


      Which gets me:



      player_id position wins
      100 offense 35
      100 defense 17
      200 offense 85
      200 defense 52
      300 offense 12
      300 defense 98


      Now from this point in MySQL I can just group_by the player_id then case the position, pulling in the associated wins value when it = 'offense' or 'defense' into their own columns, then wrap each case in a COALESCE() to prevent the nulls from coming through. Super fast.



      In Hive, instead of COALESCE I have to use MIN or MAX, but the result will be the same regardless.



      Here would be the primary way this data is queried:



      SELECT player_id
      , max(case when position = 'offense' then wins end) as offense_wins
      , max(case when position = 'defense' then wins end) as defense_wins
      FROM orctable
      WHERE player_id = 100
      GROUP BY player_id


      Which would result in :



      player_id offense_wins defense_wins
      100 35 17


      Now, in my real world situation the original dataset has six instances of that 'stats' array, each containing a map of 3-5 pairs. Because of this, the ORC table has player_id listed some 700 times from the repeated lateral views.



      The entire table is 300k rows, and the player_id in the real world example is duplicated on this table just over 700 times.



      Question 1 - is this the only and/or proper way to transform the data into the desired end result?
      Question 2 - should this query be taking between 5 and 10 seconds to complete? The same dataset on a small MySQL server would do this in milliseconds.










      share|improve this question














      Assume I have this data:



      player_id stats
      100 ["position":"offense","wins":35,"position":"defense","wins":17]
      200 ["position":"offense","wins":85,"position":"defense","wins":52]
      300 ["position":"offense","wins":12,"position":"defense","wins":98]


      And I want to display it as such:



      player_id offense_wins defense_wins
      100 35 17
      200 85 52
      300 12 98


      The original data above is currently thrown into an ORC table using:



      SELECT p.player_id
      , s.position
      , s.wins
      FROM player_stats p
      LATERAL VIEW EXPLODE(p.stats) sTable as s


      Which gets me:



      player_id position wins
      100 offense 35
      100 defense 17
      200 offense 85
      200 defense 52
      300 offense 12
      300 defense 98


      Now from this point in MySQL I can just group_by the player_id then case the position, pulling in the associated wins value when it = 'offense' or 'defense' into their own columns, then wrap each case in a COALESCE() to prevent the nulls from coming through. Super fast.



      In Hive, instead of COALESCE I have to use MIN or MAX, but the result will be the same regardless.



      Here would be the primary way this data is queried:



      SELECT player_id
      , max(case when position = 'offense' then wins end) as offense_wins
      , max(case when position = 'defense' then wins end) as defense_wins
      FROM orctable
      WHERE player_id = 100
      GROUP BY player_id


      Which would result in :



      player_id offense_wins defense_wins
      100 35 17


      Now, in my real world situation the original dataset has six instances of that 'stats' array, each containing a map of 3-5 pairs. Because of this, the ORC table has player_id listed some 700 times from the repeated lateral views.



      The entire table is 300k rows, and the player_id in the real world example is duplicated on this table just over 700 times.



      Question 1 - is this the only and/or proper way to transform the data into the desired end result?
      Question 2 - should this query be taking between 5 and 10 seconds to complete? The same dataset on a small MySQL server would do this in milliseconds.







      hive aggregation






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      asked Nov 13 '18 at 21:51









      squirrelchewsquirrelchew

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