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Posted to dev@calcite.apache.org by "Paul Jackson (JIRA)" <ji...@apache.org> on 2018/01/22 18:09:00 UTC
[jira] [Created] (CALCITE-2146) Errant CyclicMetadataException in
multithreaded context
Paul Jackson created CALCITE-2146:
-------------------------------------
Summary: Errant CyclicMetadataException in multithreaded context
Key: CALCITE-2146
URL: https://issues.apache.org/jira/browse/CALCITE-2146
Project: Calcite
Issue Type: Bug
Components: core
Affects Versions: 1.15.0
Reporter: Paul Jackson
Assignee: Julian Hyde
The code that protects against cyclic metadata is not thread-safe. A typical stack trace looks like:
{{Caused by: org.apache.calcite.rel.metadata.CyclicMetadataException}}
{{ at org.apache.calcite.rel.metadata.CyclicMetadataException.<clinit>(CyclicMetadataException.java:28)}}
{{ at GeneratedMetadataHandler_Collation.collations(Unknown Source)}}
{{ at GeneratedMetadataHandler_Collation.collations_$(Unknown Source)}}
{{ at GeneratedMetadataHandler_Collation.collations(Unknown Source)}}
{{ at org.apache.calcite.rel.metadata.RelMetadataQuery.collations(RelMetadataQuery.java:563)}}
{{ at org.apache.calcite.rel.metadata.RelMdCollation.collations(RelMdCollation.java:117)}}
{{ at GeneratedMetadataHandler_Collation.collations_$(Unknown Source)}}
{{ at GeneratedMetadataHandler_Collation.collations(Unknown Source)}}
{{ at GeneratedMetadataHandler_Collation.collations_$(Unknown Source)}}
{{ at GeneratedMetadataHandler_Collation.collations(Unknown Source)}}
{{ at org.apache.calcite.rel.metadata.RelMetadataQuery.collations(RelMetadataQuery.java:563)}}
{{ at org.apache.calcite.rel.metadata.RelMdCollation.project(RelMdCollation.java:207)}}
{{ at org.apache.calcite.rel.logical.LogicalProject$1.get(LogicalProject.java:117)}}
{{ at org.apache.calcite.rel.logical.LogicalProject$1.get(LogicalProject.java:115)}}
{{ at org.apache.calcite.plan.RelTraitSet.replaceIfs(RelTraitSet.java:238)}}
{{ at org.apache.calcite.rel.logical.LogicalProject.create(LogicalProject.java:113)}}
{{ at org.apache.calcite.rel.logical.LogicalProject.create(LogicalProject.java:103)}}
{{ at org.apache.calcite.rel.core.RelFactories$ProjectFactoryImpl.createProject(RelFactories.java:127)}}
{{ at org.apache.calcite.tools.RelBuilder.project(RelBuilder.java:1064)}}
Generally, the use case that causes this is one where we have a set of SQL templates represented as RelNodes, which we use as a starting point for queries. If different threads operate on the same RelNode, they may work on the same cluster, and therefore the same RelMetadataQuery instance, which contains a map instance that is used to detect Cyclic Metadata.
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