Parquet support for timestamp data type

[chliang71]

Description

Currently the Parquet reader does not seem to support TIMESTAMP data type. We ran into exception at here, where it complains TypeKind::TIMESTAMP is not supported.

Then I found this draft PR to support INT96 timestamp. But we also have Parquet files with INT64 microseconds TIMESTAMP values. I have done some experimental changes internally to support this, but would like to see if there is any plans/advices/concerns/blockers in the community.

@xiaoxmeng Could you possibly provide some insight into this matter? Thanks!

CC @ying

[mskapilks]

Is the support for INT64 planned in future? Is someone working on this?

[aditi-pandit]

@yingsu00 @nmahadevuni