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Posted to issues@hive.apache.org by "Eugene Chung (Jira)" <ji...@apache.org> on 2020/07/30 05:31:00 UTC
[jira] [Updated] (HIVE-23954) count(*) with count(distinct) gives
wrong results with hive.optimize.countdistinct=true
[ https://issues.apache.org/jira/browse/HIVE-23954?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Eugene Chung updated HIVE-23954:
--------------------------------
Description:
{code:java}
select count(*), count(distinct mycol) from db1.table1 where partitioned_column = '...'{code}
is not working properly when hive.optimize.countdistinct is true. By default, it's true for all 3.x versions.
In the two plans below, the aggregations part in the Output of Group By Operator of Map 1 are different.
- hive.optimize.countdistinct=false
{code:java}
+----------------------------------------------------+
| Explain |
+----------------------------------------------------+
| Plan optimized by CBO. |
| |
| Vertex dependency in root stage |
| Reducer 2 <- Map 1 (SIMPLE_EDGE) |
| |
| Stage-0 |
| Fetch Operator |
| limit:-1 |
| Stage-1 |
| Reducer 2 |
| File Output Operator [FS_7] |
| Group By Operator [GBY_5] (rows=1 width=24) |
| Output:["_col0","_col1"],aggregations:["count(VALUE._col0)","count(DISTINCT KEY._col0:0._col0)"] |
| <-Map 1 [SIMPLE_EDGE] |
| SHUFFLE [RS_4] |
| Group By Operator [GBY_3] (rows=343640771 width=4160) |
| Output:["_col0","_col1","_col2"],aggregations:["count()","count(DISTINCT mid)"],keys:mid |
| Select Operator [SEL_2] (rows=343640771 width=4160) |
| Output:["mid"] |
| TableScan [TS_0] (rows=343640771 width=4160) |
| db1@table1,table1,Tbl:COMPLETE,Col:NONE,Output:["mid"] |
| |
+----------------------------------------------------+{code}
- hive.optimize.countdistinct=true
{code:java}
+----------------------------------------------------+
| Explain |
+----------------------------------------------------+
| Plan optimized by CBO. |
| |
| Vertex dependency in root stage |
| Reducer 2 <- Map 1 (SIMPLE_EDGE) |
| |
| Stage-0 |
| Fetch Operator |
| limit:-1 |
| Stage-1 |
| Reducer 2 |
| File Output Operator [FS_7] |
| Group By Operator [GBY_14] (rows=1 width=16) |
| Output:["_col0","_col1"],aggregations:["count(_col1)","count(_col0)"] |
| Group By Operator [GBY_11] (rows=343640771 width=4160) |
| Output:["_col0","_col1"],aggregations:["count(VALUE._col0)"],keys:KEY._col0 |
| <-Map 1 [SIMPLE_EDGE] |
| SHUFFLE [RS_10] |
| PartitionCols:_col0 |
| Group By Operator [GBY_9] (rows=343640771 width=4160) |
| Output:["_col0","_col1"],aggregations:["count()"],keys:mid |
| Select Operator [SEL_2] (rows=343640771 width=4160) |
| Output:["mid"] |
| TableScan [TS_0] (rows=343640771 width=4160) |
| db1@table1,table1,Tbl:COMPLETE,Col:NONE,Output:["mid"] |
| |
+----------------------------------------------------+
{code}
was:
select count(*), count(distinct mycol) from db1.table1 where partitioned_column = '...'
is not working properly when hive.optimize.countdistinct is true. By default, it's true for all 3.x versions.
In the two plans below, the aggregations part in the Output of Group By Operator of Map 1 are different.
- hive.optimize.countdistinct=false
{code:java}
+----------------------------------------------------+
| Explain |
+----------------------------------------------------+
| Plan optimized by CBO. |
| |
| Vertex dependency in root stage |
| Reducer 2 <- Map 1 (SIMPLE_EDGE) |
| |
| Stage-0 |
| Fetch Operator |
| limit:-1 |
| Stage-1 |
| Reducer 2 |
| File Output Operator [FS_7] |
| Group By Operator [GBY_5] (rows=1 width=24) |
| Output:["_col0","_col1"],aggregations:["count(VALUE._col0)","count(DISTINCT KEY._col0:0._col0)"] |
| <-Map 1 [SIMPLE_EDGE] |
| SHUFFLE [RS_4] |
| Group By Operator [GBY_3] (rows=343640771 width=4160) |
| Output:["_col0","_col1","_col2"],aggregations:["count()","count(DISTINCT mid)"],keys:mid |
| Select Operator [SEL_2] (rows=343640771 width=4160) |
| Output:["mid"] |
| TableScan [TS_0] (rows=343640771 width=4160) |
| db1@table1,table1,Tbl:COMPLETE,Col:NONE,Output:["mid"] |
| |
+----------------------------------------------------+{code}
- hive.optimize.countdistinct=true
{code:java}
+----------------------------------------------------+
| Explain |
+----------------------------------------------------+
| Plan optimized by CBO. |
| |
| Vertex dependency in root stage |
| Reducer 2 <- Map 1 (SIMPLE_EDGE) |
| |
| Stage-0 |
| Fetch Operator |
| limit:-1 |
| Stage-1 |
| Reducer 2 |
| File Output Operator [FS_7] |
| Group By Operator [GBY_14] (rows=1 width=16) |
| Output:["_col0","_col1"],aggregations:["count(_col1)","count(_col0)"] |
| Group By Operator [GBY_11] (rows=343640771 width=4160) |
| Output:["_col0","_col1"],aggregations:["count(VALUE._col0)"],keys:KEY._col0 |
| <-Map 1 [SIMPLE_EDGE] |
| SHUFFLE [RS_10] |
| PartitionCols:_col0 |
| Group By Operator [GBY_9] (rows=343640771 width=4160) |
| Output:["_col0","_col1"],aggregations:["count()"],keys:mid |
| Select Operator [SEL_2] (rows=343640771 width=4160) |
| Output:["mid"] |
| TableScan [TS_0] (rows=343640771 width=4160) |
| db1@table1,table1,Tbl:COMPLETE,Col:NONE,Output:["mid"] |
| |
+----------------------------------------------------+
{code}
> count(*) with count(distinct) gives wrong results with hive.optimize.countdistinct=true
> ---------------------------------------------------------------------------------------
>
> Key: HIVE-23954
> URL: https://issues.apache.org/jira/browse/HIVE-23954
> Project: Hive
> Issue Type: Bug
> Components: Logical Optimizer
> Affects Versions: 3.0.0, 3.1.0
> Reporter: Eugene Chung
> Priority: Major
>
> {code:java}
> select count(*), count(distinct mycol) from db1.table1 where partitioned_column = '...'{code}
>
> is not working properly when hive.optimize.countdistinct is true. By default, it's true for all 3.x versions.
> In the two plans below, the aggregations part in the Output of Group By Operator of Map 1 are different.
>
> - hive.optimize.countdistinct=false
> {code:java}
> +----------------------------------------------------+
> | Explain |
> +----------------------------------------------------+
> | Plan optimized by CBO. |
> | |
> | Vertex dependency in root stage |
> | Reducer 2 <- Map 1 (SIMPLE_EDGE) |
> | |
> | Stage-0 |
> | Fetch Operator |
> | limit:-1 |
> | Stage-1 |
> | Reducer 2 |
> | File Output Operator [FS_7] |
> | Group By Operator [GBY_5] (rows=1 width=24) |
> | Output:["_col0","_col1"],aggregations:["count(VALUE._col0)","count(DISTINCT KEY._col0:0._col0)"] |
> | <-Map 1 [SIMPLE_EDGE] |
> | SHUFFLE [RS_4] |
> | Group By Operator [GBY_3] (rows=343640771 width=4160) |
> | Output:["_col0","_col1","_col2"],aggregations:["count()","count(DISTINCT mid)"],keys:mid |
> | Select Operator [SEL_2] (rows=343640771 width=4160) |
> | Output:["mid"] |
> | TableScan [TS_0] (rows=343640771 width=4160) |
> | db1@table1,table1,Tbl:COMPLETE,Col:NONE,Output:["mid"] |
> | |
> +----------------------------------------------------+{code}
>
> - hive.optimize.countdistinct=true
> {code:java}
> +----------------------------------------------------+
> | Explain |
> +----------------------------------------------------+
> | Plan optimized by CBO. |
> | |
> | Vertex dependency in root stage |
> | Reducer 2 <- Map 1 (SIMPLE_EDGE) |
> | |
> | Stage-0 |
> | Fetch Operator |
> | limit:-1 |
> | Stage-1 |
> | Reducer 2 |
> | File Output Operator [FS_7] |
> | Group By Operator [GBY_14] (rows=1 width=16) |
> | Output:["_col0","_col1"],aggregations:["count(_col1)","count(_col0)"] |
> | Group By Operator [GBY_11] (rows=343640771 width=4160) |
> | Output:["_col0","_col1"],aggregations:["count(VALUE._col0)"],keys:KEY._col0 |
> | <-Map 1 [SIMPLE_EDGE] |
> | SHUFFLE [RS_10] |
> | PartitionCols:_col0 |
> | Group By Operator [GBY_9] (rows=343640771 width=4160) |
> | Output:["_col0","_col1"],aggregations:["count()"],keys:mid |
> | Select Operator [SEL_2] (rows=343640771 width=4160) |
> | Output:["mid"] |
> | TableScan [TS_0] (rows=343640771 width=4160) |
> | db1@table1,table1,Tbl:COMPLETE,Col:NONE,Output:["mid"] |
> | |
> +----------------------------------------------------+
> {code}
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