[IMPALA-5657] FunctionCallExpr.toSql() and clone() ignore "IGNORE NULLS" case

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: Impala 2.8.0, Impala 2.9.0, Impala 2.10.0
• Fix Version/s: Impala 2.10.0
• Component/s: Frontend
• Labels: correctness
• Target Version: Impala 2.10.0
• Epic Color: ghx-label-5
• Assignee: Bharath Vissapragada
• Reporter: Bharath Vissapragada
• Created: 12/Jul/17 22:27
• Updated: 20/Jul/17 21:13
• Resolved: 20/Jul/17 21:13

Description

@Override
  public String toSqlImpl() {
    if (label_ != null) return label_;
    // Merge agg fns should have an explicit label.
    Preconditions.checkState(!isMergeAggFn());
    StringBuilder sb = new StringBuilder();
    sb.append(fnName_).append("(");
    if (params_.isStar()) sb.append("*");
    if (params_.isDistinct()) sb.append("DISTINCT ");
    sb.append(Joiner.on(", ").join(childrenToSql())).append(")");
    return sb.toString();
  }

protected FunctionCallExpr(FunctionCallExpr other) {
    super(other);
    fnName_ = other.fnName_;
    isAnalyticFnCall_ = other.isAnalyticFnCall_;
    isInternalFnCall_ = other.isInternalFnCall_;
    mergeAggInputFn_ = other.mergeAggInputFn_ == null ?
        null : (FunctionCallExpr)other.mergeAggInputFn_.clone();
    // Clone the params in a way that keeps the children_ and the params.exprs()
    // in sync. The children have already been cloned in the super c'tor.
    if (other.params_.isStar()) {
      Preconditions.checkState(children_.isEmpty());
      params_ = FunctionParams.createStarParam();
    } else {
      params_ = new FunctionParams(other.params_.isDistinct(), children_);  <------- other.params_.isIgnoreNulls() is ignored.
    }
    label_ = other.label_;
  }

We don't include the "IGNORE NULLS" clause if present, causing it to break the cases which rely on it, for example an InlineViewRef. A sample repro.

[localhost:21000] > create foo(a int, b int);
[localhost:21000] > create view test_view as select * from (select last_value(b IGNORE NULLS) OVER (PARTITION BY a order by b) from test) x;
[localhost:21000] > show create view test_view;
Query: show create view test_view
+------------------------------------------------------------------------------------------------+
| result                                                                                         |
+------------------------------------------------------------------------------------------------+
| CREATE VIEW incrstat.test_view AS                                                              |
| SELECT * FROM (SELECT last_value(b) OVER (PARTITION BY a ORDER BY b ASC) FROM incrstat.test) x |
+------------------------------------------------------------------------------------------------+