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https://issues.apache.org/jira/browse/CALCITE-7616?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Mihai Budiu resolved CALCITE-7616.
----------------------------------
Fix Version/s: 1.43.0
Resolution: Fixed
Fixed in
[https://github.com/apache/calcite/commit/7424c0ae3fe4641925460935522fbc8b4600b8fe]
Thank you for the contribution [~leishp]
> ProjectToLogicalProjectAndWindowRule should only match logical Project nodes
> ----------------------------------------------------------------------------
>
> Key: CALCITE-7616
> URL: https://issues.apache.org/jira/browse/CALCITE-7616
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.42.0
> Reporter: leishp
> Assignee: leishp
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.43.0
>
>
> When a JDBC schema's dialect supports window functions (e.g. MySQL,
> PostgreSQL), a query with CTE and RANK() throws AssertionError during
> VolcanoPlanner optimization:
> {code:java}
> AssertionError: Relational expression
> LogicalWindow.JDBC.TEST.[]
> has calling-convention JDBC.TEST but does not implement the required
> interface
> 'interface org.apache.calcite.adapter.jdbc.JdbcRel' of that convention
> {code}
> h3. Reproduction
> A JDBC schema whose dialect reports {{supportsWindowFunctions() = true}}
> (e.g. MySQL), and a window query:
> {code:sql}
> SELECT empno, RANK() OVER (ORDER BY sal DESC) AS rnk
> FROM emp
> {code}
> h3. Root cause
> {{ProjectToLogicalProjectAndWindowRule}} passes the parent {{{}Project{}}}'s
> traitSet directly to {{LogicalWindow.create()}} via {{{}CalcRelSplitter{}}}.
> When the parent is a {{JdbcProject}} (JDBC convention), the generated
> {{LogicalWindow}} inherits the JDBC convention but does not implement the
> {{JdbcRel}} interface, causing an AssertionError in
> {{{}VolcanoPlanner.registerImpl{}}}.
> {code:java}
> // ProjectToWindowRule.java:161 — passes project.getTraitSet() directly
> final LogicalCalc calc =
> new LogicalCalc(project.getCluster(), project.getTraitSet(), // JDBC
> convention leaks in
> project.getHints(), input, program);
> {code}
> This is related to CALCITE-3352 (wrong collation on generated Window) — both
> bugs share the same root cause: {{ProjectToWindowRule}} blindly propagates
> the parent's traitSet to the generated {{{}LogicalWindow{}}}. Danny Chen
> commented on CALCITE-3352:
> {quote}We should limit this rule to only match logical nodes because it is a
> plan rewrite.
> {quote}
> h3. Fix
> Narrow the rule's operand from {{Project.class}} to {{LogicalProject.class}},
> so it no longer matches non-logical projects such as {{JdbcProject}}. This
> rule is a *logical plan rewrite* (it
> emits a {{LogicalWindow}} of Convention.NONE), so it must only apply to
> logical nodes — exactly as Danny Chen advised on CALCITE-3352. With the
> operand narrowed, the windowed expression stays
> in {{JdbcProject}} and is pushed down to the database by {{JdbcProjectRule}}
> when the dialect supports window functions.
> {code:java}
> // ProjectToWindowRule.java — ProjectToLogicalProjectAndWindowRuleConfig
> .withOperandSupplier(b ->
> b.operand(LogicalProject.class) // was Project.class
> .predicate(Project::containsOver)
> .anyInputs())
> {code}
> h3. Impact
> - When dialect supports window functions: window function is pushed down to
> database via {{{}JdbcProject{}}}. Correct behavior.
> - When dialect does NOT support window functions:
> {{ProjectToLogicalProjectAndWindowRule}} fires on {{LogicalProject(NONE)}} as
> before. No change.
> - No existing tests broken (verified {{RelOptRulesTest}} 902/902 passed).
> h3. Scope
> This is a targeted fix for the convention issue only. The collation issue
> (CALCITE-3352) is tracked separately.
> h3. Test
> Added {{JdbcAdapterTest#testWindowFunctionJdbcConvention}} plus a nested
> {{WindowSupportingJdbcSchemaFactory}}, in the *existing* {{JdbcAdapterTest}}
> (not a new top-level class, to avoid
> changing the Gradle test-class execution order). It runs against an
> in-memory HSQLDB with a MySQL dialect override ({{supportsWindowFunctions() =
> true}}) and asserts the planner no longer
> throws the "calling-convention" AssertionError.
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