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Posted to issues@ignite.apache.org by "Mikhail Cherkasov (JIRA)" <ji...@apache.org> on 2018/03/05 18:01:00 UTC
[jira] [Commented] (IGNITE-7642) Ignite fails with OOM if query has
"NULLS LAST"
[ https://issues.apache.org/jira/browse/IGNITE-7642?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16386438#comment-16386438 ]
Mikhail Cherkasov commented on IGNITE-7642:
-------------------------------------------
[~vozerov] suggested to create h2 index with NULLS LAST modifier:
cols.add(tbl.indexColumn(col.getColumnId(),
(idxDesc.descending(field) ? SortOrder.DESCENDING : SortOrder.ASCENDING)) *| SortOrder.NULLS_LAST*)"
I checked this approach works fine. I think we should introduce in Ignite API configuration for NULLS_LAST.
> Ignite fails with OOM if query has "NULLS LAST"
> -----------------------------------------------
>
> Key: IGNITE-7642
> URL: https://issues.apache.org/jira/browse/IGNITE-7642
> Project: Ignite
> Issue Type: Bug
> Components: sql
> Affects Versions: 2.3
> Reporter: Mikhail Cherkasov
> Priority: Major
> Fix For: 2.5
>
> Attachments: OrderByNullsLastTest.java
>
>
> I have an index for "a" filed of "A" type and the following SQL works fine:
> SELECT * FROM A ORDER BY a LIMIT 0 + 50
>
> but as soon as I added "NULLS LAST" it starts to fail with OOM error:
> SELECT * FROM A ORDER BY a NULLS LAST LIMIT 0 + 50
> However for both queries, EXPLAIN says that it the uses index, I don't see why it should fail, but looks like ignite tryes to load all memory into heap and sort there, and this leads to OOM.
>
> A reproducer is attached.
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