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From "Yongzhi Chen (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-16572) Rename a partition should not drop its column stats
Date Mon, 08 May 2017 15:01:04 GMT

    [ https://issues.apache.org/jira/browse/HIVE-16572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16000866#comment-16000866
] 

Yongzhi Chen commented on HIVE-16572:
-------------------------------------

LGTM  +1

> Rename a partition should not drop its column stats
> ---------------------------------------------------
>
>                 Key: HIVE-16572
>                 URL: https://issues.apache.org/jira/browse/HIVE-16572
>             Project: Hive
>          Issue Type: Bug
>          Components: Statistics
>            Reporter: Chaoyu Tang
>            Assignee: Chaoyu Tang
>         Attachments: HIVE-16572.1.patch, HIVE-16572.patch
>
>
> The column stats for the table sample_pt partition (dummy=1) is as following:
> {code}
> hive> describe formatted sample_pt partition (dummy=1) code;
> OK
> # col_name            	data_type           	min                 	max                
	num_nulls           	distinct_count      	avg_col_len         	max_col_len         	num_trues
          	num_falses          	comment             
> 	 	 	 	 	 	 	 	 	 	 
> code                	string              	                    	                    	0
                  	303                 	6.985               	7                   	       
            	                    	from deserializer   
> Time taken: 0.259 seconds, Fetched: 3 row(s)
> {code}
> But when this partition is renamed, say
> alter table sample_pt partition (dummy=1) rename to partition (dummy=11);
> The COLUMN_STATS in partition description are true, but column stats are actually all
deleted.
> {code}
> hive> describe formatted sample_pt partition (dummy=11);
> OK
> # col_name            	data_type           	comment             
> 	 	 
> code                	string              	                    
> description         	string              	                    
> salary              	int                 	                    
> total_emp           	int                 	                    
> 	 	 
> # Partition Information	 	 
> # col_name            	data_type           	comment             
> 	 	 
> dummy               	int                 	                    
> 	 	 
> # Detailed Partition Information	 	 
> Partition Value:    	[11]                	 
> Database:           	default             	 
> Table:              	sample_pt           	 
> CreateTime:         	Thu Mar 30 23:03:59 EDT 2017	 
> LastAccessTime:     	UNKNOWN             	 
> Location:           	file:/user/hive/warehouse/apache/sample_pt/dummy=11	 
> Partition Parameters:	 	 
> 	COLUMN_STATS_ACCURATE	{\"BASIC_STATS\":\"true\",\"COLUMN_STATS\":{\"code\":\"true\",\"description\":\"true\",\"salary\":\"true\",\"total_emp\":\"true\"}}
> 	numFiles            	1                   
> 	numRows             	200                 
> 	rawDataSize         	10228               
> 	totalSize           	10428               
> 	transient_lastDdlTime	1490929439          
> 	 	 
> # Storage Information	 	 
> SerDe Library:      	org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe	 
> InputFormat:        	org.apache.hadoop.mapred.TextInputFormat	 
> OutputFormat:       	org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat	 
> Compressed:         	No                  	 
> Num Buckets:        	-1                  	 
> Bucket Columns:     	[]                  	 
> Sort Columns:       	[]                  	 
> Storage Desc Params:	 	 
> 	serialization.format	1                   
> Time taken: 6.783 seconds, Fetched: 37 row(s)
> ===
> hive> describe formatted sample_pt partition (dummy=11) code;
> OK
> # col_name            	data_type           	comment             	 	 	 	 	 	 	 	 
> 	 	 	 	 	 	 	 	 	 	 
> code                	string              	from deserializer   	 	 	 	 	 	 	 	 
> Time taken: 9.429 seconds, Fetched: 3 row(s)
> {code}
> The column stats should not be drop when a partition is renamed.



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