Feng Zhu created CALCITE-3498:
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Summary: Unnest operation's ordinality should be deterministic
Key: CALCITE-3498
URL: https://issues.apache.org/jira/browse/CALCITE-3498
Project: Calcite
Issue Type: Bug
Components: core
Affects Versions: 1.21.0
Environment: **_**_**
Reporter: Feng Zhu
Assignee: Feng Zhu
Current now, the compution of unnest operation's ordinality is conducted in
*_current()_* method (
[https://github.com/apache/calcite/blob/3853118b4d1d48f7d3970b5488baf7ca78d5028e/core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java#L2764).]
Consequently, when the method is called, the ordinality will be incremented,
leading to incorrect and un-deterministic result.
We use a simple query for illustration.
{code:java}
Query:
==============================================================
select v, o
from unnest(array[100,200]) with ordinality as t1(v, o)
where v > 1
Expected Result
==============================================================
V=100; O=1
V=200; O=2
{code}
However, we get the follow incorrect result.
{code:java}
V=100; O=2
V=200; O=4
{code}
We can infer to the code generated. It can be seen thatÂ
inputEnumerator.current() is called twice, one for filter (v>1) and one for
select (v, o).
{code:java}
public org.apache.calcite.linq4j.Enumerable bind(final
org.apache.calcite.DataContext root) {
final org.apache.calcite.linq4j.Enumerable _inputEnumerable = ..............
final org.apache.calcite.linq4j.Enumerable _inputEnumerable0 =
child.selectMany(org.apache.calcite.runtime.SqlFunctions.flatProduct(new int[] {
-1}, true, new
org.apache.calcite.runtime.SqlFunctions.FlatProductInputType[] {
org.apache.calcite.runtime.SqlFunctions.FlatProductInputType.SCALAR}));
return new org.apache.calcite.linq4j.AbstractEnumerable(){
public org.apache.calcite.linq4j.Enumerator enumerator() {
return new org.apache.calcite.linq4j.Enumerator(){
public final org.apache.calcite.linq4j.Enumerator inputEnumerator =
_inputEnumerable0.enumerator();
public void reset() {
inputEnumerator.reset();
} public boolean moveNext() {
while (inputEnumerator.moveNext()) {
if
(org.apache.calcite.runtime.SqlFunctions.toInt(((org.apache.calcite.runtime.FlatLists.ComparableList)
inputEnumerator.current()).get(0)) > 1) {
return true;
}
}
return false;
} public void close() {
inputEnumerator.close();
} public Object current() {
final org.apache.calcite.runtime.FlatLists.ComparableList current
= (org.apache.calcite.runtime.FlatLists.ComparableList)
inputEnumerator.current();
return new Object[] {
current.get(0),
current.get(1)};
} };
} };
}
public Class getElementType() {
return java.lang.Object[].class;
}
{code}
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