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https://issues.apache.org/jira/browse/SPARK-58205?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vinod KC updated SPARK-58205:
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Description:
Several JSON, CSV, and XML expressions hold mutable state in @transient lazy
val evaluator fields but did not override stateful: Boolean (which defaults to
false).
Because of this, freshCopyIfContainsStatefulExpression() never made fresh
copies of these expressions, so when the same expression object was referenced
more than once in a query plan — e.g., df.select(from_json(col, schema),
from_json(col, schema)) — both references shared the same underlying evaluator
instance. In interpreted execution this caused data-race corruption and
incorrect results.
The affected expressions were:
- GetJsonObject, JsonTuple, JsonToStructs, StructsToJson, SchemaOfJson (JSON)
- CsvToStructs, StructsToCsv, SchemaOfCsv (CSV)
- XmlToStructs, StructsToXml (XML)
was:
Seven JSON/CSV/XML expressions (JsonToStructs, GetJsonObject, JsonTuple,
CsvToStructs, StructsToCsv, XmlToStructs, StructsToXml) maintain mutable state
in @transient lazy val evaluator fields but do not override stateful.
As a result, freshCopyIfContainsStatefulExpression() never copies them, so when
two projections share the same expression node (e.g. via ConvertToLocalRelation
or pipelined execution), threads race on the shared evaluator object and
silently corrupt results.
> Mark JSON/CSV/XML expressions stateful to prevent shared-evaluator data races
> -----------------------------------------------------------------------------
>
> Key: SPARK-58205
> URL: https://issues.apache.org/jira/browse/SPARK-58205
> Project: Spark
> Issue Type: Sub-task
> Components: SQL
> Affects Versions: 3.5.0, 4.1.0, 4.0.0, 4.2.0, 4.3.0
> Reporter: Vinod KC
> Priority: Major
> Labels: pull-request-available
>
> Several JSON, CSV, and XML expressions hold mutable state in @transient lazy
> val evaluator fields but did not override stateful: Boolean (which defaults
> to false).
> Because of this, freshCopyIfContainsStatefulExpression() never made fresh
> copies of these expressions, so when the same expression object was
> referenced more than once in a query plan — e.g., df.select(from_json(col,
> schema), from_json(col, schema)) — both references shared the same underlying
> evaluator instance. In interpreted execution this caused data-race corruption
> and incorrect results.
> The affected expressions were:
> - GetJsonObject, JsonTuple, JsonToStructs, StructsToJson, SchemaOfJson (JSON)
> - CsvToStructs, StructsToCsv, SchemaOfCsv (CSV)
> - XmlToStructs, StructsToXml (XML)
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