Vladimir Sitnikov created CALCITE-4263:
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Summary: Clarify RelNode#estimateRowCount behavior with regards to
nulls
Key: CALCITE-4263
URL: https://issues.apache.org/jira/browse/CALCITE-4263
Project: Calcite
Issue Type: Sub-task
Components: core
Affects Versions: 1.25.0
Reporter: Vladimir Sitnikov
{{RelNode#estimateRowCount}} implementation must return non-nullable value, and
it often uses metadata which might return {{null}}
For instance,
{code:java}
class Correlate {
@Override public double estimateRowCount(RelMetadataQuery mq) {
double leftRowCount = mq.getRowCount(left); // <-- NPE here
switch (joinType) {
case SEMI:
case ANTI:
return leftRowCount;
default:
return leftRowCount * mq.getRowCount(right); // <-- NPE here
}
}
{code}
There should be documentation on the desired behavior in case metadata returns
"unknown", and the code needs adjustment as lot of the implementation perform
blind unboxing.
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