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https://issues.apache.org/jira/browse/IGNITE-29038?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vladislav Pyatkov reassigned IGNITE-29038:
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Assignee: Vladislav Pyatkov
> Fix recursive CTE subqueries and multiple consumers
> ---------------------------------------------------
>
> Key: IGNITE-29038
> URL: https://issues.apache.org/jira/browse/IGNITE-29038
> Project: Ignite
> Issue Type: Bug
> Reporter: Vladislav Pyatkov
> Assignee: Vladislav Pyatkov
> Priority: Major
> Labels: calcite, ignite-2, sql
>
> Recursive CTE (IGNITE-27822) support currently has two blocking issues.
> h3. A self-reference inside a subquery may return an incorrect result instead
> of an error:
> {code}
> WITH RECURSIVE numbers(n) AS (
> SELECT 1
> UNION ALL
> SELECT (SELECT n + 1 FROM numbers)
> FROM (VALUES (0))
> )
> SELECT n
> FROM numbers
> FETCH FIRST 3 ROWS ONLY;
> {code}
> Such queries are not supported by most RDBMSs. Ignite should reject them with
> a descriptive IgniteSQLException.
> h3. Referencing the same recursive CTE multiple times in the outer query
> fails because consumers share the recursion state:
> {code}
> WITH RECURSIVE numbers(n) AS (
> SELECT 1
> UNION ALL
> SELECT n + 1 FROM numbers WHERE n < 3
> )
> SELECT l.n, r.n
> FROM numbers l
> JOIN numbers r ON l.n = r.n;
> {code}
> This is supported by other RDBMSs and should return (1,1), (2,2), and (3,3).
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