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https://issues.apache.org/jira/browse/HIVE-21075?focusedWorklogId=688011&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-688011
 ]

ASF GitHub Bot logged work on HIVE-21075:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 30/Nov/21 13:36
            Start Date: 30/Nov/21 13:36
    Worklog Time Spent: 10m 
      Work Description: yongzhi commented on a change in pull request #2826:
URL: https://github.com/apache/hive/pull/2826#discussion_r759284468



##########
File path: 
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/ObjectStore.java
##########
@@ -5326,6 +5355,23 @@ private void preDropStorageDescriptor(MStorageDescriptor 
msd) {
     removeUnusedColumnDescriptor(mcd);
   }
 
+  /**
+   * Get a list of storage descriptors that reference a particular Column 
Descriptor
+   * @param oldCD the column descriptor to get storage descriptors for
+   * @return a list of storage descriptors
+   */
+  private List<MStorageDescriptor> 
listStorageDescriptorsWithCD(MColumnDescriptor oldCD, Query query) {

Review comment:
       This method will release the query.  rollbackAndCleanup(success, query); 
That's why the original patch leak query as it checks if !success.




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Issue Time Tracking
-------------------

    Worklog Id:     (was: 688011)
    Time Spent: 5h 20m  (was: 5h 10m)

> Metastore: Drop partition performance downgrade with Postgres DB
> ----------------------------------------------------------------
>
>                 Key: HIVE-21075
>                 URL: https://issues.apache.org/jira/browse/HIVE-21075
>             Project: Hive
>          Issue Type: Bug
>          Components: Metastore
>    Affects Versions: 3.0.0
>            Reporter: Yongzhi Chen
>            Assignee: Oleksiy Sayankin
>            Priority: Major
>              Labels: pull-request-available
>         Attachments: HIVE-21075.2.patch
>
>          Time Spent: 5h 20m
>  Remaining Estimate: 0h
>
> In order to workaround oracle not supporting limit statement caused 
> performance issue, HIVE-9447 makes all the backend DB run select count(1) 
> from SDS where SDS.CD_ID=? to check if the specific CD_ID is referenced in 
> SDS table before drop a partition. This select count(1) statement does not 
> scale well in Postgres, and there is no index for CD_ID column in SDS table.
> For a SDS table with with 1.5 million rows, select count(1) has average 700ms 
> without index, while in 10-20ms with index. But the statement before 
> HIVE-9447( SELECT * FROM "SDS" "A0" WHERE "A0"."CD_ID" = $1 limit 1) uses 
> less than 10ms .



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