[jira] [Commented] (ASTERIXDB-2832) Enumerate Additional Approaches to Specify Empty Arrays for Array Index Optimization

["Glenn Justo Galvizo (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ASTERIXDB-2832?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17379265#comment-17379265 ] 

Glenn Justo Galvizo commented on ASTERIXDB-2832:
------------------------------------------------

By adding grammar support for ANY/SOME (AND EVERY)? , we could force users to use this and avoid having to search for additional patterns.

> Enumerate Additional Approaches to Specify Empty Arrays for Array Index Optimization
> ------------------------------------------------------------------------------------
>
>                 Key: ASTERIXDB-2832
>                 URL: https://issues.apache.org/jira/browse/ASTERIXDB-2832
>             Project: Apache AsterixDB
>          Issue Type: Improvement
>            Reporter: Glenn Justo Galvizo
>            Assignee: Glenn Justo Galvizo
>            Priority: Major
>
> To use array indexes for universal quantification queries, the query must also indicate the array is non-empty. If this is not true, then we cannot use the index because array indexes do not store empty arrays. 
>  
> Currently, the use must specify this clause by using the LEN function on the array and enforcing that this is greater than 0 (e.g. LEN(myarray) > 0 AND ...). But this is not the only way to specify that an array is empty. A user could also:
>  # Index an element of the array, with the expectation this element is not null.
>  # Use an existential clause on that same array.
>  # Use some clause with an array function, where the result of this comparison is not null.
>  # ...
>  



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