[jira] [Resolved] (CALCITE-3498) Unnest operation's ordinality should be deterministic

["Ruben Q L (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-3498?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ruben Q L resolved CALCITE-3498.
--------------------------------
    Fix Version/s: 1.22.0
       Resolution: Fixed

> 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
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.22.0
>
>          Time Spent: 2h
>  Remaining Estimate: 0h
>
> 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 can 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 that *inputEnumerator.current()* has been called two times, 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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