feat(parquet): Add boolean rle decoder for Parquet

[jkhaliqi]

RLE/BP is an Encoding for Boolean values for Parquet Version 2 files.
https://parquet.apache.org/docs/file-format/data-pages/encodings/
Fixes: #10943

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[ethanyzhang]

@yingsu00 can you also take a look at this PR? Thank you!

[czentgr]

The magic number 4 is used multiple times. Please make it a static const here and use an appropriate name for it.

You don't need super:: here. There is no ambiguity here.

[czentgr]

Nit: Do we need this comment once the 4 is not magic number anymore?

[jkhaliqi]

Right removing comment since it is not necessary, thank you!

[czentgr]

This should be a constexpr.

[jkhaliqi]

updated to constexpr, thank you!

[czentgr]

The function itself doesn't need to be constexpr. It is the if condition that should be constexpr.

if constexpr (hasNulls)

That means if the template argument is false this if expression is not generated.

[czentgr]

Shouldn't this be RleBpDecoder::skip(numValues) to disambiguate the function from this->skip(numValues)?

[czentgr]

Lets also initialize it to 0.

[czentgr]

Why is the size of the vector 20?

[jkhaliqi]

Sorry was using this output buffer for some other testing since it's not being used anymore will delete this line of code

[czentgr]

There is no problem if toSkip > 0 but we already advanced current by 1 on line 97? I suppose this someting about what visitor represents? This might need a comment to explain why this is ok.

Or maybe some comment on how the algorithm works when the read occurs.

[czentgr]

This needs to be named numBytes_.

[czentgr]

Same comment above about using super vs the base class name to disambiguate.

[czentgr]

Now that you've replaced super with the actual base class we don't need this anymore. I did not see that you defined super here. This explains why it was working before. But someone not familiar with Java would be confused so better to be explicit.

[jkhaliqi]

Thank you removed this line!

[czentgr]

Lets replace the std::to_string with fmt provided in the VELOX_FAIL like so:

VELOX_FAIL("Received invalid length : {} (corrupt data page?)", len);

for all occurrences.

[jkhaliqi]

Thank you, updated!

[czentgr]

The function itself doesn't need to be constexpr. It is the if condition that should be constexpr.

if constexpr (hasNulls)

That means if the template argument is false this if expression is not generated.

[czentgr]

len is not modified here and we don't need a reference.

[jkhaliqi]

updated, thank you!

[czentgr]

What is not clear to me is why you modify the base class member here. You have your own bufferStart_ so why not processing and modifying this using the base class methods (which you have to some degree).
The base class member (with the same name) is initialized in the constructor. But because you declared a new member of the same name that is never used on line 118 you need to explicitly refer to the base class here when this member is inherited.

[jkhaliqi]

Good catch forgot to remove my own bufferStart_ which was being used for something else cleaned up the code with removing it, thank you!

[ethanyzhang]

@majetideepak should we have another pass?

[majetideepak]

@jkhaliqi can you clarify why we cannot use the existing velox::parquet::RleBpDataDecoder class? Thanks.

[jkhaliqi]

@majetideepak Seems to be too many errors while using RleBpDataDecoder with things like processRle function and so i'm not sure if it's implementation is complete, @yingsu00 might have more on that, if possible?

[majetideepak]

@jkhaliqi if the fastPath is not supported for bool type, we can skip that via dwio::common::useFastPath().. && !std::is_same_v<typename Visitor::DataType, bool>?
The remaining code seems very similar. Can you check?

[majetideepak]

@jkhaliqi Two minor comments. This looks good!

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@kevinwilfong has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

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@kevinwilfong merged this pull request in 9b2ad44.