Mostafa Mokhtar created HIVE-7991:
-------------------------------------

             Summary: Incorrect calculation of number of rows in 
JoinStatsRule.process results in overflow
                 Key: HIVE-7991
                 URL: https://issues.apache.org/jira/browse/HIVE-7991
             Project: Hive
          Issue Type: Bug
          Components: Statistics
    Affects Versions: 0.13.1
            Reporter: Mostafa Mokhtar
            Assignee: Prasanth J
             Fix For: 0.14.0


For queries with rollup and cube the number of rows calculation in 
GroupByStatsRule should be multiplied by number of elements in grouping set.
A side effect of this defect is that reducers will under estimate data size and 
end up with small number of tasks which negatively affects query runtime.  

{code}
            // since we do not know if hash-aggregation will be enabled or 
disabled
            // at runtime we will assume that map-side group by does not do any
            // reduction.hence no group by rule will be applied

            // map-side grouping set present. if grouping set is present then
            // multiply the number of rows by number of elements in grouping set
            if (gop.getConf().isGroupingSetsPresent()) {
              int multiplier = gop.getConf().getListGroupingSets().size();

              // take into account the map-side parallelism as well, default is 
1
              multiplier *= mapSideParallelism;
              newNumRows = multiplier * stats.getNumRows();
              long dataSize = multiplier * stats.getDataSize();
              stats.setNumRows(newNumRows);
              stats.setDataSize(dataSize);
              for (ColStatistics cs : colStats) {
                if (cs != null) {
                  long oldNumNulls = cs.getNumNulls();
                  long newNumNulls = multiplier * oldNumNulls;
                  cs.setNumNulls(newNumNulls);
                }
              }
            } else {

              // map side no grouping set
              newNumRows = stats.getNumRows() * mapSideParallelism;
              updateStats(stats, newNumRows, true);
            }
          
{code}


Query 
{code}
select  *
from (select i_category
            ,i_class
            ,i_brand
            ,i_product_name
            ,d_year
            ,d_qoy
            ,d_moy
            ,s_store_id
            ,sumsales
            ,rank() over (partition by i_category order by sumsales desc) rk
      from (select i_category
                  ,i_class
                  ,i_brand
                  ,i_product_name
                  ,d_year
                  ,d_qoy
                  ,d_moy
                  ,s_store_id
                  ,sum(coalesce(ss_sales_price*ss_quantity,0)) sumsales
            from store_sales
                ,date_dim
                ,store
                ,item
       where  store_sales.ss_sold_date_sk=date_dim.d_date_sk
          and store_sales.ss_item_sk=item.i_item_sk
          and store_sales.ss_store_sk = store.s_store_sk
          and d_month_seq between 1193 and 1193+11
          and ss_sold_date between '1999-06-01' and '2000-05-31'
       group by i_category, i_class, i_brand, i_product_name, d_year, d_qoy, 
d_moy,s_store_id with rollup)dw1) dw2
where rk <= 100
order by i_category
        ,i_class
        ,i_brand
        ,i_product_name
        ,d_year
        ,d_qoy
        ,d_moy
        ,s_store_id
        ,sumsales
        ,rk
limit 100
{code}

Plan generated , note the data size for Map 1
{code}
STAGE DEPENDENCIES:
  Stage-1 is a root stage
  Stage-0 depends on stages: Stage-1

STAGE PLANS:
  Stage: Stage-1
    Tez
      Edges:
        Map 1 <- Map 5 (BROADCAST_EDGE), Map 6 (BROADCAST_EDGE), Map 7 
(BROADCAST_EDGE)
        Reducer 2 <- Map 1 (SIMPLE_EDGE)
        Reducer 3 <- Reducer 2 (SIMPLE_EDGE)
        Reducer 4 <- Reducer 3 (SIMPLE_EDGE)
      DagName: mmokhtar_20140903154848_7cf1519f-e95c-47ab-9f10-6d2130cd5734:1
      Vertices:
        Map 1 
            Map Operator Tree:
                TableScan
                  alias: store_sales
                  filterExpr: (((ss_sold_date_sk is not null and ss_store_sk is 
not null) and ss_item_sk is not null) and ss_sold_date BETWEEN '1999-06-01' AND 
'2000-05-31') (type: boolean)
                  Statistics: Num rows: 110339135 Data size: 4817453454 Basic 
stats: COMPLETE Column stats: NONE
                  Filter Operator
                    predicate: ((ss_sold_date_sk is not null and ss_store_sk is 
not null) and ss_item_sk is not null) (type: boolean)
                    Statistics: Num rows: 13792392 Data size: 602181687 Basic 
stats: COMPLETE Column stats: NONE
                    Map Join Operator
                      condition map:
                           Inner Join 0 to 1
                      condition expressions:
                        0 {ss_sold_date_sk} {ss_item_sk} {ss_store_sk} 
{ss_quantity} {ss_sales_price} {ss_sold_date}
                        1 {d_date_sk} {d_month_seq} {d_year} {d_moy} {d_qoy}
                      keys:
                        0 ss_sold_date_sk (type: int)
                        1 d_date_sk (type: int)
                      outputColumnNames: _col0, _col2, _col7, _col10, _col13, 
_col23, _col27, _col30, _col33, _col35, _col37
                      input vertices:
                        1 Map 6
                      Statistics: Num rows: 15171632 Data size: 662399872 Basic 
stats: COMPLETE Column stats: NONE
                      Map Join Operator
                        condition map:
                             Inner Join 0 to 1
                        condition expressions:
                          0 {_col0} {_col2} {_col7} {_col10} {_col13} {_col23} 
{_col27} {_col30} {_col33} {_col35} {_col37}
                          1 {s_store_sk} {s_store_id}
                        keys:
                          0 _col7 (type: int)
                          1 s_store_sk (type: int)
                        outputColumnNames: _col0, _col2, _col7, _col10, _col13, 
_col23, _col27, _col30, _col33, _col35, _col37, _col58, _col59
                        input vertices:
                          1 Map 5
                        Statistics: Num rows: 16688796 Data size: 728639872 
Basic stats: COMPLETE Column stats: NONE
                        Map Join Operator
                          condition map:
                               Inner Join 0 to 1
                          condition expressions:
                            0 {_col0} {_col2} {_col7} {_col10} {_col13} 
{_col23} {_col27} {_col30} {_col33} {_col35} {_col37} {_col58} {_col59}
                            1 {i_item_sk} {i_brand} {i_class} {i_category} 
{i_product_name}
                          keys:
                            0 _col2 (type: int)
                            1 i_item_sk (type: int)
                          outputColumnNames: _col0, _col2, _col7, _col10, 
_col13, _col23, _col27, _col30, _col33, _col35, _col37, _col58, _col59, _col90, 
_col98, _col100, _col102, _col111
                          input vertices:
                            1 Map 7
                          Statistics: Num rows: 18357676 Data size: 801503872 
Basic stats: COMPLETE Column stats: NONE
                          Filter Operator
                            predicate: (((((_col0 = _col27) and (_col2 = 
_col90)) and (_col7 = _col58)) and _col30 BETWEEN 1193 AND 1204) and _col23 
BETWEEN '1999-06-01' AND '2000-05-31') (type: boolean)
                            Statistics: Num rows: 573677 Data size: 25046979 
Basic stats: COMPLETE Column stats: NONE
                            Select Operator
                              expressions: _col102 (type: string), _col100 
(type: string), _col98 (type: string), _col111 (type: string), _col33 (type: 
int), _col37 (type: int), _col35 (type: int), _col59 (type: string), _col13 
(type: float), _col10 (type: int)
                              outputColumnNames: _col102, _col100, _col98, 
_col111, _col33, _col37, _col35, _col59, _col13, _col10
                              Statistics: Num rows: 573677 Data size: 25046979 
Basic stats: COMPLETE Column stats: NONE
                              Group By Operator
                                aggregations: sum(COALESCE((_col13 * _col10),0))
                                keys: _col102 (type: string), _col100 (type: 
string), _col98 (type: string), _col111 (type: string), _col33 (type: int), 
_col37 (type: int), _col35 (type: int), _col59 (type: string), '0' (type: 
string)
                                mode: hash
                                outputColumnNames: _col0, _col1, _col2, _col3, 
_col4, _col5, _col6, _col7, _col8, _col9
                                Statistics: Num rows: 573677 Data size: 
25046979 Basic stats: COMPLETE Column stats: NONE
                                Reduce Output Operator
                                  key expressions: _col0 (type: string), _col1 
(type: string), _col2 (type: string), _col3 (type: string), _col4 (type: int), 
_col5 (type: int), _col6 (type: int), _col7 (type: string), _col8 (type: string)
                                  sort order: +++++++++
                                  Map-reduce partition columns: _col0 (type: 
string), _col1 (type: string), _col2 (type: string), _col3 (type: string), 
_col4 (type: int), _col5 (type: int), _col6 (type: int), _col7 (type: string), 
_col8 (type: string)
                                  Statistics: Num rows: 573677 Data size: 
25046979 Basic stats: COMPLETE Column stats: NONE
                                  value expressions: _col9 (type: double)
        Map 5 
            Map Operator Tree:
                TableScan
                  alias: store
                  filterExpr: s_store_sk is not null (type: boolean)
                  Statistics: Num rows: 212 Data size: 405680 Basic stats: 
COMPLETE Column stats: COMPLETE
                  Filter Operator
                    predicate: s_store_sk is not null (type: boolean)
                    Statistics: Num rows: 212 Data size: 22048 Basic stats: 
COMPLETE Column stats: COMPLETE
                    Reduce Output Operator
                      key expressions: s_store_sk (type: int)
                      sort order: +
                      Map-reduce partition columns: s_store_sk (type: int)
                      Statistics: Num rows: 212 Data size: 22048 Basic stats: 
COMPLETE Column stats: COMPLETE
                      value expressions: s_store_id (type: string)
            Execution mode: vectorized
        Map 6 
            Map Operator Tree:
                TableScan
                  alias: date_dim
                  filterExpr: (d_date_sk is not null and d_month_seq BETWEEN 
1193 AND 1204) (type: boolean)
                  Statistics: Num rows: 73049 Data size: 81741831 Basic stats: 
COMPLETE Column stats: COMPLETE
                  Filter Operator
                    predicate: (d_date_sk is not null and d_month_seq BETWEEN 
1193 AND 1204) (type: boolean)
                    Statistics: Num rows: 36524 Data size: 730480 Basic stats: 
COMPLETE Column stats: COMPLETE
                    Reduce Output Operator
                      key expressions: d_date_sk (type: int)
                      sort order: +
                      Map-reduce partition columns: d_date_sk (type: int)
                      Statistics: Num rows: 36524 Data size: 730480 Basic 
stats: COMPLETE Column stats: COMPLETE
                      value expressions: d_month_seq (type: int), d_year (type: 
int), d_moy (type: int), d_qoy (type: int)
            Execution mode: vectorized
        Map 7 
            Map Operator Tree:
                TableScan
                  alias: item
                  filterExpr: i_item_sk is not null (type: boolean)
                  Statistics: Num rows: 48000 Data size: 68732712 Basic stats: 
COMPLETE Column stats: COMPLETE
                  Filter Operator
                    predicate: i_item_sk is not null (type: boolean)
                    Statistics: Num rows: 48000 Data size: 18672000 Basic 
stats: COMPLETE Column stats: COMPLETE
                    Reduce Output Operator
                      key expressions: i_item_sk (type: int)
                      sort order: +
                      Map-reduce partition columns: i_item_sk (type: int)
                      Statistics: Num rows: 48000 Data size: 18672000 Basic 
stats: COMPLETE Column stats: COMPLETE
                      value expressions: i_brand (type: string), i_class (type: 
string), i_category (type: string), i_product_name (type: string)
            Execution mode: vectorized
        Reducer 2 
            Reduce Operator Tree:
              Group By Operator
                aggregations: sum(VALUE._col0)
                keys: KEY._col0 (type: string), KEY._col1 (type: string), 
KEY._col2 (type: string), KEY._col3 (type: string), KEY._col4 (type: int), 
KEY._col5 (type: int), KEY._col6 (type: int), KEY._col7 (type: string), 
KEY._col8 (type: string)
                mode: mergepartial
                outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, 
_col6, _col7, _col8, _col9
                Statistics: Num rows: 286838 Data size: 12523467 Basic stats: 
COMPLETE Column stats: NONE
                Select Operator
                  expressions: _col0 (type: string), _col1 (type: string), 
_col2 (type: string), _col3 (type: string), _col4 (type: int), _col5 (type: 
int), _col6 (type: int), _col7 (type: string), _col9 (type: double)
                  outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, 
_col6, _col7, _col8
                  Statistics: Num rows: 286838 Data size: 12523467 Basic stats: 
COMPLETE Column stats: NONE
                  Reduce Output Operator
                    key expressions: _col0 (type: string), _col8 (type: double)
                    sort order: +-
                    Map-reduce partition columns: _col0 (type: string)
                    Statistics: Num rows: 286838 Data size: 12523467 Basic 
stats: COMPLETE Column stats: NONE
                    TopN Hash Memory Usage: 0.04
                    value expressions: _col0 (type: string), _col1 (type: 
string), _col2 (type: string), _col3 (type: string), _col4 (type: int), _col5 
(type: int), _col6 (type: int), _col7 (type: string), _col8 (type: double)
        Reducer 3 
            Reduce Operator Tree:
              Extract
                Statistics: Num rows: 286838 Data size: 12523467 Basic stats: 
COMPLETE Column stats: NONE
                PTF Operator
                  Statistics: Num rows: 286838 Data size: 12523467 Basic stats: 
COMPLETE Column stats: NONE
                  Filter Operator
                    predicate: (_wcol0 <= 100) (type: boolean)
                    Statistics: Num rows: 95612 Data size: 4174459 Basic stats: 
COMPLETE Column stats: NONE
                    Select Operator
                      expressions: _col0 (type: string), _col1 (type: string), 
_col2 (type: string), _col3 (type: string), _col4 (type: int), _col5 (type: 
int), _col6 (type: int), _col7 (type: string), _col8 (type: double), _wcol0 
(type: int)
                      outputColumnNames: _col0, _col1, _col2, _col3, _col4, 
_col5, _col6, _col7, _col8, _col9
                      Statistics: Num rows: 95612 Data size: 4174459 Basic 
stats: COMPLETE Column stats: NONE
                      Reduce Output Operator
                        key expressions: _col0 (type: string), _col1 (type: 
string), _col2 (type: string), _col3 (type: string), _col4 (type: int), _col5 
(type: int), _col6 (type: int), _col7 (type: string), _col8 (type: double), 
_col9 (type: int)
                        sort order: ++++++++++
                        Statistics: Num rows: 95612 Data size: 4174459 Basic 
stats: COMPLETE Column stats: NONE
                        TopN Hash Memory Usage: 0.04
        Reducer 4 
            Reduce Operator Tree:
              Select Operator
                expressions: KEY.reducesinkkey0 (type: string), 
KEY.reducesinkkey1 (type: string), KEY.reducesinkkey2 (type: string), 
KEY.reducesinkkey3 (type: string), KEY.reducesinkkey4 (type: int), 
KEY.reducesinkkey5 (type: int), KEY.reducesinkkey6 (type: int), 
KEY.reducesinkkey7 (type: string), KEY.reducesinkkey8 (type: double), 
KEY.reducesinkkey9 (type: int)
                outputColumnNames: _col0, _col1, _col2, _col3, _col4, _col5, 
_col6, _col7, _col8, _col9
                Statistics: Num rows: 95612 Data size: 4174459 Basic stats: 
COMPLETE Column stats: NONE
                Limit
                  Number of rows: 100
                  Statistics: Num rows: 100 Data size: 4300 Basic stats: 
COMPLETE Column stats: NONE
                  File Output Operator
                    compressed: false
                    Statistics: Num rows: 100 Data size: 4300 Basic stats: 
COMPLETE 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
            Execution mode: vectorized

  Stage: Stage-0
    Fetch Operator
      limit: 100
      Processor Tree:
        ListSink
{code}




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