[jira] [Commented] (FLINK-7205) Add UUID supported in TableAPI/SQL

["Fabian Hueske (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-7205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16089799#comment-16089799 ] 

Fabian Hueske commented on FLINK-7205:
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The spatial uniqueness could be obtained from the id of the parallel task instance. This is available in a {{RichFunction}} via {{RuntimeContext.getIndexOfThisSubtask()}}.

> Add UUID supported in TableAPI/SQL
> ----------------------------------
>
>                 Key: FLINK-7205
>                 URL: https://issues.apache.org/jira/browse/FLINK-7205
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>    Affects Versions: 1.4.0
>            Reporter: sunjincheng
>
> UUID() returns a value that conforms to UUID version 1 as described in RFC 4122. The value is a 128-bit number represented as a utf8 string of five hexadecimal numbers in aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee format:
> The first three numbers are generated from the low, middle, and high parts of a timestamp. The high part also includes the UUID version number.
> The fourth number preserves temporal uniqueness in case the timestamp value loses monotonicity (for example, due to daylight saving time).
> The fifth number is an IEEE 802 node number that provides spatial uniqueness. A random number is substituted if the latter is not available (for example, because the host device has no Ethernet card, or it is unknown how to find the hardware address of an interface on the host operating system). In this case, spatial uniqueness cannot be guaranteed. Nevertheless, a collision should have very low probability.
> See: [RFC 4122: http://www.ietf.org/rfc/rfc4122.txt|http://www.ietf.org/rfc/rfc4122.txt]
> See detailed semantics:
>    MySql: [https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_uuid|https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_uuid]
> Welcome anybody feedback -:).



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