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https://issues.apache.org/jira/browse/IMPALA-10243?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zoltán Borók-Nagy resolved IMPALA-10243.
----------------------------------------
    Fix Version/s: Impala 4.0
       Resolution: Fixed

> ConcurrentModificationException during parallel INSERTs
> -------------------------------------------------------
>
>                 Key: IMPALA-10243
>                 URL: https://issues.apache.org/jira/browse/IMPALA-10243
>             Project: IMPALA
>          Issue Type: Bug
>            Reporter: Zoltán Borók-Nagy
>            Assignee: Zoltán Borók-Nagy
>            Priority: Major
>             Fix For: Impala 4.0
>
>
> Impala might throw a ConcurrentModificationException during a high load of 
> INSERTs to the same table.
> The exception happens during thrift serialization of TUpdateCatalogResponse 
> which have a reference to the metastore table. The serialization happens 
> without a lock, so another thread might modify the metastore table object in 
> the meantime. This can potentially happen in 
> CatalogOpExecutor.updateCatalog() which updates the catalog version and 
> unsets table column statistics. A high load of INSERT statements increase the 
> probability of the concurrent modification.
> I think the problem is that in Table.toThrift() we set a reference to the 
> metastore table object instead of deep copying it:
> [https://github.com/apache/impala/blob/481ea4ab0d476a4aa491f99c2a4e376faddc0b03/fe/src/main/java/org/apache/impala/catalog/Table.java#L505]
> The stack trace looks like the following:
> [1] java.util.HashMap$HashIterator.nextNode (HashMap.java:1,445)
>  [2] java.util.HashMap$EntryIterator.next (HashMap.java:1,479)
>  [3] java.util.HashMap$EntryIterator.next (HashMap.java:1,477)
>  [4] org.apache.hadoop.hive.metastore.api.Table$TableStandardScheme.write 
> (Table.java:2,641)
>  [5] org.apache.hadoop.hive.metastore.api.Table$TableStandardScheme.write 
> (Table.java:2,324)
>  [6] org.apache.hadoop.hive.metastore.api.Table.write (Table.java:2,082)
>  [7] org.apache.impala.thrift.TTable$TTableStandardScheme.write 
> (TTable.java:1,829)
>  [8] org.apache.impala.thrift.TTable$TTableStandardScheme.write 
> (TTable.java:1,569)
>  [9] org.apache.impala.thrift.TTable.write (TTable.java:1,357)
>  [10] 
> org.apache.impala.thrift.TCatalogObject$TCatalogObjectStandardScheme.write 
> (TCatalogObject.java:1,433)
>  [11] 
> org.apache.impala.thrift.TCatalogObject$TCatalogObjectStandardScheme.write 
> (TCatalogObject.java:1,272)
>  [12] org.apache.impala.thrift.TCatalogObject.write 
> (TCatalogObject.java:1,086)
>  [13] 
> org.apache.impala.thrift.TCatalogUpdateResult$TCatalogUpdateResultStandardScheme.write
>  (TCatalogUpdateResult.java:908)
>  [14] 
> org.apache.impala.thrift.TCatalogUpdateResult$TCatalogUpdateResultStandardScheme.write
>  (TCatalogUpdateResult.java:780)
>  [15] org.apache.impala.thrift.TCatalogUpdateResult.write 
> (TCatalogUpdateResult.java:682)
>  [16] 
> org.apache.impala.thrift.TUpdateCatalogResponse$TUpdateCatalogResponseStandardScheme.write
>  (TUpdateCatalogResponse.java:363)
>  [17] 
> org.apache.impala.thrift.TUpdateCatalogResponse$TUpdateCatalogResponseStandardScheme.write
>  (TUpdateCatalogResponse.java:325)
>  [18] org.apache.impala.thrift.TUpdateCatalogResponse.write 
> (TUpdateCatalogResponse.java:273)
>  [19] org.apache.thrift.TSerializer.serialize (TSerializer.java:79)
>  [20] org.apache.impala.service.JniCatalog.updateCatalog (JniCatalog.java:314)



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