[
https://issues.apache.org/jira/browse/PARQUET-200?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14347817#comment-14347817
]
Ryan Blue commented on PARQUET-200:
-----------------------------------
Updated the spec and documentation in [PR
#23|https://github.com/apache/incubator-parquet-format/pull/23].
> Add nanosecond time and timestamp annotations
> ---------------------------------------------
>
> Key: PARQUET-200
> URL: https://issues.apache.org/jira/browse/PARQUET-200
> Project: Parquet
> Issue Type: Improvement
> Components: parquet-format
> Reporter: Ryan Blue
>
> When the date/time type annotations were added, we decided not to add
> precisions smaller than milliseconds because there wasn't a clear
> requirement. I think that the requirement is for nanosecond precision. The
> SQL spec requires at least microsecond, and many databases support
> nanosecond, including SQL engines on Hadoop: Hive, Phoenix, and Impala.
> I propose adding the following type annotations:
> * {{TIME_NANOS}}: annotates an int64 (8 bytes), represents the number of
> nanoseconds from midnight.
> * {{TIMESTAMP_NANOS}}: annotates a 12-byte fixed, containing first an 8-byte
> number of milliseconds from unix epoch and, second, a 4-byte number of
> nanoseconds from the 8-byte time (nanoseconds from the last millisecond).
> Both values are little-endian.
> The timestamp type allows object models that don't support nanosecond times
> (or don't need it for processing) to easily ignore the second value.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
