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https://issues.apache.org/jira/browse/PARQUET-1977?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17285099#comment-17285099
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ASF GitHub Bot commented on PARQUET-1977:
-----------------------------------------
gszadovszky commented on pull request #868:
URL: https://github.com/apache/parquet-mr/pull/868#issuecomment-779685215
> Great findings! I will review it sometime this week.
>
> BTW, I see you keep finding issues like this. Are you doing some testing?
The Impala team started working on bloom filters. They are the ones coming
to me with these issues :)
(It is really fortunate that they started working on this before our
release.)
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> Invalid data_page_offset
> ------------------------
>
> Key: PARQUET-1977
> URL: https://issues.apache.org/jira/browse/PARQUET-1977
> Project: Parquet
> Issue Type: Bug
> Components: parquet-mr
> Affects Versions: 1.12.0
> Reporter: Gabor Szadovszky
> Assignee: Gabor Szadovszky
> Priority: Major
>
> The thrift field
> [{{data_page_offset}}|https://github.com/gszadovszky/parquet-format/blob/master/src/main/thrift/parquet.thrift#L733]
> is filled with incorrect value. Currently, it always points to the beginning
> of the column chunk which is not correct according to the spec in case there
> is a dictionary page. This is not a regression as it was written incorrectly
> since the beginning of parquet-mr.
> Meanwhile PARQUET-1850 fixed that we never wrote the field
> [{{dictionary_page_offset}}|https://github.com/gszadovszky/parquet-format/blob/master/src/main/thrift/parquet.thrift#L739].
> After the fix we correctly write this field if there is a dictionary filter.
> The problem is we are using the same value to fill both fields. So there are
> two possibilities:
> * There is no dictionary page in the column chunk so {{data_page_offset}} is
> filled with the correct value while {{dictionary_page_offset}} is not filled
> which is still correct. We are good.
> * There is a dictionary page at the beginning of the column chunk so
> {{data_page_offset}} and {{dictionary_page_offset}} are both contains the
> same value. This is not only a regression but it causes issues in other
> implementations (e.g. Impala) where footer validation is more strict than in
> parquet-mr because {{dictionary_page_offset}} shall be less than
> {{data_page_offset}} at all time if it is filled.
> So, we need to fill {{data_page_offset}} correctly.
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