Bug #6421: XQuery "group by" - result data duplication - Saxon - Saxonica Developer Community

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Bug #6421

closed

XQuery "group by" - result data duplication

Added by Taras Chervinka 2 months ago. Updated 2 months ago.

Status:

Duplicate

Priority:

Normal

Assignee:

Michael Kay

Category:

Internals

Sprint/Milestone:

Start date:

2024-05-13

Due date:

% Done:

Estimated time:

Legacy ID:

Applies to branch:

10, 11, 12

Fix Committed on Branch:

Fixed in Maintenance Release:

Platforms:

.NET, Java

Description

let $a := <root>
<user id="1">A</user>
<user id="2">B</user>
<user id="1">C</user>
<user id="1">D</user>
<user id="1">E</user>
</root>

return string-join(
	for $usr in $a/user
    let $id := data($usr/@id)
    where $id = '1'
    group by $id
    return
    	for $u in $a/user
        where $u/@id = $usr/@id
        return $u/text(), ", ")

we got a case from a customer and simplified it. The expression produces different results in 9.5, 10 and 11 9.5 - A, C, D, E 10,11 - A, A, A, A, C, C, C, C, D, D, D, D, E, E, E, E

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Updated by Taras Chervinka 2 months ago

9.5 - A, C, D, E
10.8, 11.5 - A, A, A, A, C, C, C, C, D, D, D, D, E, E, E, E

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Updated by Michael Kay 2 months ago

Subject changed from result data duplication to XQuery "group by" - result data duplication

Thanks for reporting it. Initial inquiries show:

As far as I can see, the problem (that is, the duplicated output) occurs only in EE (which means it is probably an optimization error): and it occurs in releases up to 12.3, but not in 12.4. However, I can't immediately find a known bug that was cleared in 12.4 with similar symptoms. The Git change log also shows no significant changes in the "group by" code.

The -explain output from 12.3 and 12.4 appears identical -- which goes against the theory of an optimization bug.

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Updated by Michael Kay 2 months ago

Found it, it looks like bug #6207.

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Updated by Taras Chervinka 2 months ago

Correct, it is EE version, I have tested the same with 11.6 and it behaves the same but I see #6207 fix is committed to 11 branch. Any ETA when it can be released with 11? We have not migrated yet to 12

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Updated by Taras Chervinka 2 months ago

Is that possible to release the fix for version 10?

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Updated by Michael Kay 2 months ago

Our immediate priority is to get a 12.5 maintenance release out, then turn our attentions to SaxonJS. There may be a final maintenance release on the 11 branch some time, but it's not a priority (each maintenance release typically ties up the whole team for a week, sometimes longer if it's been a long time since the previous one).

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