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https://issues.apache.org/jira/browse/HIVE-23671?focusedWorklogId=452850&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-452850
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ASF GitHub Bot logged work on HIVE-23671:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 30/Jun/20 07:41
            Start Date: 30/Jun/20 07:41
    Worklog Time Spent: 10m 
      Work Description: deniskuzZ commented on a change in pull request #1087:
URL: https://github.com/apache/hive/pull/1087#discussion_r447476089



##########
File path: 
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnDbUtil.java
##########
@@ -313,6 +313,41 @@ private static void resetTxnSequence(Connection conn, 
Statement stmt) throws SQL
     }
   }
 
+  /**
+   * Restarts the txnId sequence with the given seed value.
+   * It is the responsibility of the caller to not set the sequence backward.
+   * @param conn database connection
+   * @param stmt sql statement
+   * @param seedTxnId the seed value for the sequence
+   * @throws SQLException ex
+   */
+  public static void seedTxnSequence(Connection conn, Statement stmt, long 
seedTxnId) throws SQLException {
+    String dbProduct = conn.getMetaData().getDatabaseProductName();
+    DatabaseProduct databaseProduct = determineDatabaseProduct(dbProduct);
+    switch (databaseProduct) {
+
+    case DERBY:

Review comment:
       minor: i would probably create EnumMap for SEED_FN, and use proper one 
based on db type.




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

    Worklog Id:     (was: 452850)
    Time Spent: 5h 20m  (was: 5h 10m)

> MSCK repair should handle transactional tables in certain usecases
> ------------------------------------------------------------------
>
>                 Key: HIVE-23671
>                 URL: https://issues.apache.org/jira/browse/HIVE-23671
>             Project: Hive
>          Issue Type: Improvement
>          Components: Metastore
>            Reporter: Peter Varga
>            Assignee: Peter Varga
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 5h 20m
>  Remaining Estimate: 0h
>
> The MSCK REPAIR tool does not handle transactional tables too well. It can 
> find and add new partitions the same way as for non-transactional tables, but 
> since the writeId differences are not handled, the data can not read back 
> from the new partitions.
> We could handle some usecases when the writeIds in the HMS and the underlying 
> data are not conflicting. If the HMS does not contains allocated writes for 
> the table we can seed the table with the writeIds read from the directory 
> structrure.
> Real life use cases could be:
>  * Copy data files from one cluster to another with different HMS, create the 
> table and call MSCK REPAIR
>  * If the HMS db is lost, recreate the table and call MSCK REPAIR
>  



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