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Posted to issues-all@impala.apache.org by "Quanlong Huang (Jira)" <ji...@apache.org> on 2021/03/16 06:29:00 UTC

[jira] [Updated] (IMPALA-10579) Deadloop in table metadata loading when using an invalid RemoteIterator

     [ https://issues.apache.org/jira/browse/IMPALA-10579?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Quanlong Huang updated IMPALA-10579:
------------------------------------
    Affects Version/s: Impala 3.4.0

> Deadloop in table metadata loading when using an invalid RemoteIterator
> -----------------------------------------------------------------------
>
>                 Key: IMPALA-10579
>                 URL: https://issues.apache.org/jira/browse/IMPALA-10579
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Catalog
>    Affects Versions: Impala 3.4.0
>            Reporter: Quanlong Huang
>            Assignee: Quanlong Huang
>            Priority: Critical
>
> The file listing thread in catalogd will go into a dead loop if it gets a RemoteIterator on a non-existing path. The first call of the RemoteIterator.hasNext() will throw a FileNotFoundException. However, this exception will be catched and the loop will continue, which results in a dead loop. Related codes: [https://github.com/apache/impala/blob/d89c04bf806682d3449c566ce979632bd2ac5b29/fe/src/main/java/org/apache/impala/common/FileSystemUtil.java#L789-L814]
> {code:java}
>   static class FilterIterator implements RemoteIterator<FileStatus> {
>     ...
>     public boolean hasNext() throws IOException {
>       ...
>       while (curFile_ == null) {
>         FileStatus next;
>         try {
>           if (!baseIterator_.hasNext()) return false; // <---- throws FileNotFoundException
>           ...
>           next = baseIterator_.next();
>         } catch (FileNotFoundException ex) {
>           ...
>           LOG.warn(ex.getMessage());
>           continue;  // <--------- catch the exception and continue into a dead loop
>         }
>         if (!isInIgnoredDirectory(startPath_, next)) {
>           curFile_ = next;
>           return true;
>         }
>       }
>       return true;
>     }
> {code}
> *When will the path to be loading not exist?*
>  It happens when metadata (table/partition location) in HMS still have the path. But it's actually removed from the storage.
> *When will impala get such an invalid RemoteIterator?*
>  For FileSystem implementations that don't override the FileSystem#listStatusIterator() interface, e.g. S3AFileSystem before HADOOP-17281, AzureBlobFileSystem, and GoogleHadoopFileSystem.



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