Gopal V created HIVE-17465:
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Summary: Statistics: Drill-down filters don't reduce row-counts
progressively
Key: HIVE-17465
URL: https://issues.apache.org/jira/browse/HIVE-17465
Project: Hive
Issue Type: Bug
Reporter: Gopal V
{code}
explain select count(d_date_sk) from date_dim where d_year=2001 ;
explain select count(d_date_sk) from date_dim where d_year=2001 and d_moy = 9;
explain select count(d_date_sk) from date_dim where d_year=2001 and d_moy = 9
and d_dom = 21;
{code}
All 3 queries end up with the same row-count estimates after the filter.
{code}
Map Operator Tree:
TableScan
alias: date_dim
filterExpr: (d_year = 2001) (type: boolean)
Statistics: Num rows: 73049 Data size: 82034027 Basic stats:
COMPLETE Column stats: COMPLETE
Filter Operator
predicate: (d_year = 2001) (type: boolean)
Statistics: Num rows: 363 Data size: 4356 Basic stats:
COMPLETE Column stats: COMPLETE
Map 1
Map Operator Tree:
TableScan
alias: date_dim
filterExpr: ((d_year = 2001) and (d_moy = 9)) (type: boolean)
Statistics: Num rows: 73049 Data size: 82034027 Basic stats:
COMPLETE Column stats: COMPLETE
Filter Operator
predicate: ((d_year = 2001) and (d_moy = 9)) (type: boolean)
Statistics: Num rows: 363 Data size: 5808 Basic stats:
COMPLETE Column stats: COMPLETE
Map 1
Map Operator Tree:
TableScan
alias: date_dim
filterExpr: ((d_year = 2001) and (d_moy = 9) and (d_dom =
21)) (type: boolean)
Statistics: Num rows: 73049 Data size: 82034027 Basic stats:
COMPLETE Column stats: COMPLETE
Filter Operator
predicate: ((d_year = 2001) and (d_moy = 9) and (d_dom =
21)) (type: boolean)
Statistics: Num rows: 363 Data size: 7260 Basic stats:
COMPLETE Column stats: COMPLETE
{code}
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