presto:tpch  explain select commitdate, count(*) from lineitem group by commitdate;
                                                                                                                                                                                                                                                                                                                                                                             
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 - Output[commitdate, _col1] =  [commitdate:date, count:bigint]                                                                                                                                                                                                                                                                                                              
         _col1 := count (1:28)                                                                                                                                                                                                                                                                                                                                               
     - RemoteStreamingExchange[GATHER] =  [commitdate:date, count:bigint]                                                                                                                                                                                                                                                                                                    
         - Project[projectLocality = LOCAL] =  [commitdate:date, count:bigint]                                                                                                                                                                                                                                                                                               
             - Aggregate(FINAL)[commitdate][$hashvalue] =  [commitdate:date, $hashvalue:bigint, count:bigint]                                                                                                                                                                                                                                                                
                     count := "presto.default.count"((count_8)) (1:28)                                                                                                                                                                                                                                                                                                       
                 - LocalExchange[HASH][$hashvalue] (commitdate) =  [commitdate:date, count_8:bigint, $hashvalue:bigint]                                                                                                                                                                                                                                                      
                     - RemoteStreamingExchange[REPARTITION][$hashvalue_9] =  [commitdate:date, count_8:bigint, $hashvalue_9:bigint]                                                                                                                                                                                                                                          
                         - Aggregate(PARTIAL)[commitdate][$hashvalue_10] =  [commitdate:date, $hashvalue_10:bigint, count_8:bigint]                                                                                                                                                                                                                                          
                                 count_8 := "presto.default.count"(*) (1:28)                                                                                                                                                                                                                                                                                                 
                             - ScanProject[table = TableHandle {connectorId='hive', connectorHandle='HiveTableHandle{schemaName=tpch, tableName=lineitem, analyzePartitionValues=Optional.empty}', layout='Optional[tpch.lineitem{}]'}, projectLocality = LOCAL] =  [commitdate:date, $hashvalue_10:bigint]                                                                  
                                     Estimates: {rows: 60175 (822.71kB), cpu: 300875.00, memory: 0.00, network: 0.00}/{rows: 60175 (822.71kB), cpu: 1143325.00, memory: 0.00, network: 0.00}                                                                                                                                                                                 
                                     $hashvalue_10 := combine_hash(BIGINT'0', COALESCE($operator$hash_code(commitdate), BIGINT'0')) (1:60)                                                                                                                                                                                                                                   
                                     LAYOUT: tpch.lineitem{}                                                                                                                                                                                                                                                                                                                 
                                     commitdate := commitdate:date:11:REGULAR (1:42)                                                                                                                                                                                                                                                                                         

 PruneTableScanColumns (before):                                                                                                                                                                                                                                                                                                                                             
 - Project[projectLocality = UNKNOWN] =  [commitdate_0:date]                                                                                                                                                                                                                                                                                                                 
         commitdate_0 := commitdate (1:43)                                                                                                                                                                                                                                                                                                                                   
     - GroupReference[9] =  [orderkey:bigint, partkey:bigint, suppkey:bigint, linenumber:integer, quantity:double, extendedprice:double, discount:double, tax:double, returnflag:varchar(1), linestatus:varchar(1), shipdate:date, commitdate:date, receiptdate:date, shipinstruct:varchar(25), shipmode:varchar(10), comment:varchar(44), $path:varchar, $file_size:bigint, 

 PruneTableScanColumns (after):                                                                                                                                                                                                                                                                                                                                              
 - ScanProject[table = TableHandle {connectorId='hive', connectorHandle='HiveTableHandle{schemaName=tpch, tableName=lineitem, analyzePartitionValues=Optional.empty}', layout='Optional.empty'}, projectLocality = UNKNOWN] =  [commitdate_0:date]                                                                                                                           
         commitdate_0 := commitdate (1:43)                                                                                                                                                                                                                                                                                                                                   
         commitdate := commitdate:date:11:REGULAR (1:42)                                                                                                                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                                                                                                                                             
...
                                                                                                                                                                                                                                                                                                                                  
                                                                                                                                                                                                                                                                                                                                                                             
 PushPartialAggregationThroughExchange (before):                                                                                                                                                                                                                                                                                                                             
 - Aggregate[commitdate] =  [commitdate:date, count:bigint]                                                                                                                                                                                                                                                                                                                  
         count := "presto.default.count"(*) (1:28)                                                                                                                                                                                                                                                                                                                           
     - GroupReference[4] =  [commitdate:date]                                                                                                                                                                                                                                                                                                                                
                                                                                                                                                                                                                                                                                                                                                                             
 PushPartialAggregationThroughExchange (after):                                                                                                                                                                                                                                                                                                                              
 - Aggregate(FINAL)[commitdate] =  [commitdate:date, count:bigint]                                                                                                                                                                                                                                                                                                           
         count := "presto.default.count"((count_8)) (1:28)                                                                                                                                                                                                                                                                                                                   
     - Aggregate(PARTIAL)[commitdate] =  [commitdate:date, count_8:bigint]                                                                                                                                                                                                                                                                                                   
             count_8 := "presto.default.count"(*) (1:28)                                                                                                                                                                                                                                                                                                                     
         - GroupReference[4] =  [commitdate:date]                                                                                                                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                                                                                                                                             
 PushPartialAggregationThroughExchange (before):                                                                                                                                                                                                                                                                                                                             
 - Aggregate(PARTIAL)[commitdate] =  [commitdate:date, count_8:bigint]                                                                                                                                                                                                                                                                                                       
         count_8 := "presto.default.count"(*) (1:28)                                                                                                                                                                                                                                                                                                                         
     - GroupReference[4] =  [commitdate:date]                                                                                                                                                                                                                                                                                                                                
                                                                                                                                                                                                                                                                                                                                                                             
 PushPartialAggregationThroughExchange (after):                                                                                                                                                                                                                                                                                                                              
 - LocalExchange[HASH] (commitdate) =  [commitdate:date, count_8:bigint]                                                                                                                                                                                                                                                                                                     
     - Project[projectLocality = LOCAL] =  [commitdate:date, count_8:bigint]                                                                                                                                                                                                                                                                                                 
         - Aggregate(PARTIAL)[commitdate] =  [commitdate:date, count_8:bigint]                                                                                                                                                                                                                                                                                               
                 count_8 := "presto.default.count"(*) (1:28)                                                                                                                                                                                                                                                                                                                 
             - GroupReference[5] =  [commitdate:date]
(1 row)