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https://issues.apache.org/jira/browse/HIVE-14265?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15382482#comment-15382482
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Ashutosh Chauhan commented on HIVE-14265:
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+1
> Partial stats in Join operator may lead to data size estimate of 0
> ------------------------------------------------------------------
>
> Key: HIVE-14265
> URL: https://issues.apache.org/jira/browse/HIVE-14265
> Project: Hive
> Issue Type: Bug
> Components: Statistics
> Reporter: Nita Dembla
> Assignee: Jesus Camacho Rodriguez
> Attachments: HIVE-14265.patch
>
>
> For some tables, we might not have the column stats available. However, if
> the table is partitioned, we will have the stats for partition columns.
> When we estimate the size of the data produced by a join operator, we end up
> using only the columns that are available for the calculation e.g. partition
> columns in this case.
> However, even in these cases, we should add the data size for those columns
> for which we do not have stats (_default size for the column type x estimated
> number of rows_).
> To reproduce, the following example can be used:
> {noformat}
> create table sample_partitioned (x int) partitioned by (y int);
> insert into sample_partitioned partition(y=1) values (1),(2);
> create temporary table sample as select * from sample_partitioned;
> analyze table sample compute statistics for columns;
> explain select sample_partitioned.x from sample_partitioned, sample where
> sample.y = sample_partitioned.y;
> {noformat}
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