Andy Seaborne created JENA-1113:
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Summary: FILTER(?x IN ( .... )) causes stackoverflow for very long
lists of values.
Key: JENA-1113
URL: https://issues.apache.org/jira/browse/JENA-1113
Project: Apache Jena
Issue Type: Bug
Components: ARQ
Affects Versions: Jena 3.0.1
Reporter: Andy Seaborne
Assignee: Andy Seaborne
{{FILTER(?x IN ( .... ))}} with a list of 60,000+ URIs causes a stack overflow
during execution. The list was machine generated.
{{?x IN(C1, C2, ...}} is expanded to {{?x = C1 || ?x = C2 || .... }}. In many
places, working with expressions is a tree walk ({{ExprWalker}}).
The transformation is a left-deep tree: for a 4-long list:
{noformat}
(||
(||
(|| (= ?x C1)
(= ?x C2))
(= ?x C3))
(= ?x C4))
{noformat}
so the walk is as deep as the list is long. A transformation rewrite is 3
stack frames per level. The result is a huge number of stack frames until is
exceeds the stack space available.
A right-deep list would be better but only if all processing code is aware of
this and does a loop for the right recursion.
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