Out Of Range Vector Access For Complicated Parquet Types In GetParquetColumnInfo

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Bug Description

In this article, we will explore a bug that occurs when accessing Parquet files with complicated types using Velox workers. The bug is related to out of range vector access in the getParquetColumnInfo function.

Creating a Sample Table

To demonstrate this issue, let's create a sample table with an array column of row type. We will use Java workers to create the table and insert some data.

CREATE TABLE test_array_row ( id INT, data ARRAY(ROW(field1 INT, field2 VARCHAR)) ) WITH ( format = 'PARQUET' );
INSERT INTO test_array_row (id, data) VALUES (1, ARRAY[ROW(10, 'Alice'), ROW(20, 'Bob')]), (2, ARRAY[ROW(30, 'Charlie'), ROW(40, 'David')])

Running a Simple Query

When we run a simple query using Velox workers and column index based mapping, we encounter an error.

select * from test_array_row;

The error message is:

Query 20250312_145339_00016_enrin failed:  Operator::getOutput failed for [operator: TableScan, plan node ID: 0]: vector::_M_range_check: __n (which is 5) >= this->size() (which is 4)

However, if we create the table using Velox workers, everything works fine.

System Information

To better understand the issue, let's take a look at the system information.

  • Velox System Info: v0.0.2
  • Commit: 6010f956c3735fdadf6a4a0d24a2e4e87f5ea9c6
  • CMake Version: 3.28.3
  • System: Linux-6.1.112+
  • Arch: x86_64
  • C++ Compiler: /usr/bin/c++
  • C++ Compiler Version: 12.3.0
  • C Compiler: /usr/bin/cc
  • C Compiler Version: 12.3.0
  • CMake Prefix Path: /usr/local;/usr;/;/usr/local/lib/python3.9/dist-packages/cmake/data;/usr/local;/usr/X11R6;/usr/pkg;/opt

Relevant Logs

Unfortunately, there are no relevant logs provided for this issue.

Analysis

After analyzing the issue, we can see that the problem occurs when accessing the Parquet file with complicated types using Velox workers. The getParquetColumnInfo function is responsible for retrieving the column information from the Parquet file. However, in this case, the function returns an out of range vector access error.

Possible Causes

There are several possible causes for this issue:

  1. Incorrect Parquet Reserved Words: The Parquet file may contain reserved words that are not properly handled by the getParquetColumnInfo function.
  2. Incorrect Column Index Mapping: The column index mapping may be incorrect, leading to out of range vector access.
  3. Bug in Velox Workers: There may be a bug in the Velox workers that is causing the issue.

Solution

To solve this issue, we can try the following:

  1. Add More Parquet Reserved Words: We can add more Parquet reserved words to the getParquetColumnInfo function to handle complicated types.
  2. Verify Column Index Mapping: We can verify the column index mapping to ensure that it is correct.
  3. Update Velox Workers: We can update the Velox workers to the latest version to fix any bugs that may be causing the issue.

Conclusion

Frequently Asked Questions

In this article, we will answer some frequently asked questions related to the out of range vector access bug for complicated Parquet types in the getParquetColumnInfo function.

Q: What is the out of range vector access bug?

A: The out of range vector access bug is a bug that occurs when accessing Parquet files with complicated types using Velox workers. The bug is related to out of range vector access in the getParquetColumnInfo function.

Q: What are the possible causes of the out of range vector access bug?

A: There are several possible causes of the out of range vector access bug, including:

  • Incorrect Parquet Reserved Words: The Parquet file may contain reserved words that are not properly handled by the getParquetColumnInfo function.
  • Incorrect Column Index Mapping: The column index mapping may be incorrect, leading to out of range vector access.
  • Bug in Velox Workers: There may be a bug in the Velox workers that is causing the issue.

Q: How can I fix the out of range vector access bug?

A: To fix the out of range vector access bug, you can try the following:

  • Add More Parquet Reserved Words: You can add more Parquet reserved words to the getParquetColumnInfo function to handle complicated types.
  • Verify Column Index Mapping: You can verify the column index mapping to ensure that it is correct.
  • Update Velox Workers: You can update the Velox workers to the latest version to fix any bugs that may be causing the issue.

Q: What are the benefits of fixing the out of range vector access bug?

A: Fixing the out of range vector access bug can provide several benefits, including:

  • Improved Performance: Fixing the bug can improve the performance of your application by reducing the time it takes to access Parquet files.
  • Increased Reliability: Fixing the bug can increase the reliability of your application by reducing the likelihood of errors.
  • Better Support: Fixing the bug can provide better support for complicated Parquet types, making it easier to work with these types.

Q: How can I prevent the out of range vector access bug in the future?

A: To prevent the out of range vector access bug in the future, you can follow these best practices:

  • Use the Latest Version of Velox Workers: Make sure to use the latest version of Velox workers to ensure that you have the latest bug fixes.
  • Verify Column Index Mapping: Verify the column index mapping to ensure that it is correct.
  • Test Thoroughly: Test your application thoroughly to ensure that it is working correctly.

Q: What are the next steps after fixing the out of range vector access bug?

A: After fixing the out of range vector access bug, you can take the following next steps:

  • Verify the Fix: Verify that the fix has resolved the issue.
  • Test the Fix: Test the fix to ensure that it is working correctly.
  • Deploy the Fix: Deploy the fix to production to ensure that all users have access to the fixed version.

Conclusion

In this article, we answered some frequently asked questions related to the out of range vector access bug for complicated Parquet types in the getParquetColumnInfo function. We provided information on the possible causes of the bug, how to fix it, and the benefits of fixing it. We also provided best practices for preventing the bug in the future and next steps after fixing it.